dnputnam

Finally everything is settling back down and getting back to normal.  I got a gift of a sign that makes my work area official, so I went in and started planking.  The plans say the planking is 2 1/2” X 7” and narrower.  That’s .05” X .15” so I’m planking with .07” thick figuring the sanding will take it down to .05”.  In the pictures you can see the gar board and the sheer strakes.  It looks like I will have to use a lot of filler planks at the stern, but that will be a few days yet.  I was looking at the planking of the Bluenose.  The one I was studying used 15 planks bow to stern.  It doesn’t look like I’ll be so lucky.
 
Bob
 

 

 

 

 

The chocks were fitted next.  The edges were highlighted with pencil to make the seams stand out.
 

 

 
The assemblies were then glued in place.  The aft partner was glued using the log pumps to help alignment.  
 

 
After the glue was dry, I cut the mortises for the ledges between the partners carlings and the middle carlings.  Because of the locations of the pumps and the main topsail sheet bitts, only two ledges would fit.  The multiple bolts were added and a coat of finish was applied to seal the bolts in place.  I typically dry-fit the bolts, only using glue if the hole is too large.  The last photo shows how it will look with all six pumps in position.  
 

 

 
 
 
 

Thanks everyone for the "Likes".  
 
My next project is beam set 12, which includes the main mast partners.  The beam set itself is straight-forward.  The main mast partners is similar to the fore mast partners...only larger.  The carlings are half- mortised into beams 11 and 12.  I had previously made the decision not to cut the mortises on beam 11 ahead of time because any mistakes would be very obvious.  My intention was to cut them in once I had the mortises cut on beam 12 so they would be exactly parallel.  I could not cut them to my satisfaction because the upper well was in the way of the chisel.  I did not wish to remove the upper well and possibly damage it so I faked the fore tenon.  In the pictures you can see the recess cut into the carlings for the partners as well as the difference in the thickness of the fore and aft tenons.
 

 

 

 
The next pictures show the fore and aft ends of the carlings after they were installed and before final sanding.
 

 

 
The aft partner was addressed next.  This has octagonal holes cut into it for the pumps.  Now comes the tricky part.  These log pumps extend through the previously cut holes in the lower deck main mast partner and insert into the pump intake lateral to the keel.  They also need to be perpendicular to the keel and slightly canted away from each other.  The holes in the lower deck partner needed to be "adjusted" to accommodate this three dimensional arrangement.  That's a euphemism for totally trashing the holes.  After the aft partner was temporarily glued in place, I inserted the logs down to the hold.  I made a veneer of boxwood and planked over the lower deck partners to disguise the error.  In the third photo you can see the widened hole in the lower deck partner before the repair.  The fore partner was made and the last picture shows it in place.
 

 

 

 

The main topsail sheet bitt pins are located within the upper well.  These insert onto the aft face of the lower deck beam and there is a score for the upper deck beam.  Once the well has been secured in place it will be difficult to access this area so I started them now.  The pins are 9" square above the upper deck beam.  Below that they taper on the aft face.  They are perpendicular to the keel.  Rather than make the entire bitt now and risk damage, I only made the pins up to the upper deck beam.  To maintain correct alignment I glued on two temporary cross bars away from where the cross-piece and gallows will be placed.  Holes were drilled through the score for the upper deck beam and into the beam.  Steel pins are holding the pins in place.  Holes have also been cut in the hatch cover for the main jeer bitt pins.  The pictures show the bitt pins before and after the upper well was installed.
 

 

Young America - extreme clipper 1853
Part 33 – Aft Keelson/Deadwood
 
In the first picture a section of upper keelson tier is being glued to the lower tier.
 

 
I have been using pins with small wood blocks as opposed to clamps when gluing pieces like this.  It is working well, but it is important to size the blocks (or drill the holes) accurately so just enough pin head has to be driven into the wood.  Too much and the pin will bend or be hard to remove.  Not enough and the piece will not be secured.
 
The next picture shows some of the lower keelson pieces glued in place.
 

 
The frame cross spalls are being removed as this works proceeds.  With the lower keelson glued and bolted to through the frames into the keel, the  hull frames are quite secure and no longer need them.
 
The next picture shows the fitting of the last keelson section.
 

 
The last step in fitting these last pieces is to carefully trim the aft ends of the slightly over sized piece for a neat fit against the sternpost knee.  All of the scarph joints were cut before either adjacent piece was installed.  The next picture shows the final fit.
 

 
As I mentioned earlier, the keelson in these long clippers was the main longitudinal member and so it was installed in a straight line from stem to stern, with the deadwood at each end built up on top of it.
 
The next picture shows the first two deadwood sections cut out and and set in place between the keelson and the inner post.
 

 
Once these have been roughly fit, the patterns are removed for final trimming as shown below.
 

 
The last picture shows an upper piece ready for gluing.
 

 
Glue is placed in the gap and the pins driven down for a tight joint fit.  There is still one section above this – in two pieces – that will form the curved top of the deadwood.  All of the sections are also later secured with epoxied copper bolts into the sections below and the inner post. 
 
 
Ed

Happy New Year All.....
 I started building up the livewell, with the bed logs installed, I put on the upper deck beams, and built up to them. Beam @ frame 10 was notched to allow the proper length for the hatches. Trickiest part was  finding the proper angles for the front corner posts. According to the plans the outside of the live well is oiled/stained, I am using Testers bulwark red, with a drop of brown to get that red lead look.

Hi all...
I gave the front sole a coat of Pollys ghost gray. I made a small miscalculation with the front  bedlogs. they are 1/8" thick, and I used 1/16". This worked out ok, because the 1/16 allowed the new 1/8 to fit flush against the sole, nice clean fit, with extra support. I clamped wide stock to the sole to get the proper height for the bedlogs at frame #14.
A little model gossip... i stopped by my local hobby shop for supplies, They told me Pollys paint is being discontinued. Im a little bummed about this, there paint is great... flat is true flat and there military colors match perfect. I always prefered pollys to Tamiya or Testors. Oh well.

Howdy all...
I completed the front sole and started the live well assembly. So far the front bedlogs were installed. I think my plan of attack will be to build the base of the live well, install the deck beams that support the livewell hatch, and built from the bottom up.

Can I have copies of your plans?
 
 
Hello Folks,
 
 
Over the past six months I've had great feedback on my topic here on MSW and on my blog. The chance to interact with modelers of such ability is a real privilege.
 
 
I've also received a lot of requests for high resolution copies of my plans. I’m extremely happy that people want to build the Terror, which I consider to be one of the world’s greatest exploration vessels. She deserves the attention.
 
 
I do plan to release copies of the plans at some point (and yes, I do intend to make full masting and rigging plans for her). However, I'm still at the beginning of my project, and my plans are not proven by construction. I know they will require some modification as I build. I don't want to send them out with errors, as that would just make more work for people.
 
 
When I'm finished my build and the plans are complete, I'll make them available as a set. And I'll post it here on these boards so you are the first to know.
 
 
Does that sound reasonable? I hope everyone understands!
 
E&T

Thanks, funny how problems create new idea's.
 
I laid just  one strake of the deck planking and wil only add partials to support the bulkheads for the cabins. I'll try to keep as much view to the hold as possible.
 
The caulking is very thin paper blackened with a sharpy.
 

 

 
Added some of the furniture just for fun and to see how things start to look 'dressed up'  it will be pretty crowded once the bulkheads are in
 

 
Remco
 
 

HOISTING TERROR’S COLOURS
 
HMS Terror’s paint scheme is considered to be well known. Richard Cyriax, who produced the most authoritative work on Franklin’s last expedition, states: “Both ships were flush-decked, and had black hulls, white masts, and yellow weather works...” (Cyriax 1997:39).  This passage has long been interpreted by subsequent researchers to mean that the ships had a yellow stripe along their outside hull (e.g. Parks Canada, Canadian Geographic, and published work too numerous to list here).  Cyriax based this description not on a primary source, but on a popular work by his friend, Rupert T. Gould (1928:112); unfortunately Gould appears to have misinterpreted the primary source material.
 
Gould’s information came from a remarkable parliamentary record, which documents an Admiralty investigation into two ships spotted trapped in an iceberg off the coast of Newfoundland in 1851 (Inglis 1852). The investigation focused on comparing the eyewitness testimony about the iceberg ships to the firsthand knowledge of the shipwrights who worked on Erebus and Terror. While the Admiralty determined that the iceberg ships could not be Franklin’s vessels (the size difference between the ships was too large and they were not barque-rigged ), the report contains critical primary information on the paint scheme of the Erebus and Terror from Oliver Lang, the master shipwright responsible for the 1845 refit of the vessels.  
 
The correspondence between Lang and the Admiralty is worth quoting here in its entirety (Inglis 1852:18):
 
 
Admiralty, 17 April 1852.
Sir,
I am commanded by my Lords Commissioners of the Admiralty to desire
you to call upon the officers of the yard under your superintendence to
report how Sir John Franklin's ships, the " Erebus" and " Terror," were
painted when they sailed.
 
 
I am &c.
(signed) J. H. Hay,
pro Secretary.
 
Commodore Superintendent Eden,
Woolwich.
  
 
Woolwich Yard, 17 April 1852.
 
Sir,
With reference to their Lordships' letter of this day's date, we beg to
acquaint you, that Sir John Franklin's ships, the " Erebus " and " Terror,"
were painted when they sailed, black on the outside, and weather works
inside yellow.
 
 
                                    We are, &c.
(signed)                         O. Lang,
Master Shipwright
 
 
 
Further information about the colour of the masts was also requested from Lang and appears below (Inglis 1852:35).
 
 
Admiralty, 2 June 1852.
 
Commodore Superintendent at Woolwich,
Referring to your communication of the 17th April last, upon the subject
of painting the " Erebus" and "'Terror," my Lords desire that you will state
for their information how their lower masts were painted.
 
By command of their Lordships.
(signed) W. A. B. Hamilton.
                                                                                   
Woolwich Yard, 2 June 1852.
 
Sir,
Agreeably to your minute on Captain Hamilton's letter of yesterday,
we have to acquaint you that the lower masts of the "Erebus" and "Terror"
were painted white when they left this port.
 
We are, &c.
(signed)                       O. Lang,
Master Shipwright..
 
 
 
H. Chatfteld, Assistant ditto.'
(Mr. Peake sick.)
The Commodore Superintendent.
Submitted for the information of their Lordships.
Henry Eden, Commodore Superintendent.
The Secretary of the Admiralty
 
Lang’s choice of words in the first correspondence appears to be the source of the enduring discrepancy regarding the ships’ paint schemes. It seems Gould, followed by Cyriax, and then myriad others, interpreted the phrase “weather works inside yellow” to mean a band of yellow on the outside hull of the vessel. Indeed, the “weather works”, or upper works of a ship, are those areas of the vessel above the waterline exposed to the weather, including the upper hull and bulwarks both inside towards the deck and outside on the hull. However, Lang specifically states that the “weather works inside “ were yellow, meaning that the inside bulwarks were painted yellow. He makes no mention of a stripe on the outside hull, although a solid paint scheme without a stripe would have been unusual for a Royal Navy vessel of the era.
 
Thankfully, a watercolour painting by Owen Stanley, who accompanied the ships across the North Atlantic to Greenland in 1845, provides important primary evidence which dispels much ambiguity (see below). The painting shows conclusively that the Terror and Erebus had black hulls with a white stripe along the outside weather works. The painting indicates that the white stripe was contiguous with the chock channel and that it ascended the outside stern frame of the Erebus at an angle. Another watercolour, which may also be the work of Stanley (it is clearly based on his 1845 drawing), confirms these characteristics, and also shows the yellow painting on the inside bulwarks (note also the very rusted condition of the iron bow plating). This image also suggests that the white stripe extended forward around the knee of the ship.
 
 
The presence of a single stripe along the hull, which extended around the knee of the ship and up the exterior stern frames, appears to be confirmed in other contemporary sketches by Stanley, Gore (also here), and Fitzjames, as well as by the Illustrated London News (which also confirms the white stripe on the outside stern frame, see below). 
 


 
 
A white stripe painted on the exterior weather works is entirely consistent with Royal Navy standards of the mid-19th century. Yellow and black striping, or the “Nelson Checker”, was common in the Royal Navy vessels up to about 1815. However, after ca. 1815, Royal Navy vessels began to adopt the black on white pattern first established by the American Navy around the turn of the 19th century. In fact, black hulls with white stripes remained the standard paint scheme of Royal Navy vessels well into the steam era (see Konstam 2010 for good summary).  It therefore seems obvious, given all of the available data, that Erebus and Terror were painted with the standard white on black scheme of the era, which may explain why Lang didn’t deem it necessary to mention this standard attribute to the Admiralty.
 
Most Royal Navy ships placed the white stripe over the gun ports above the waterline; when opened, the ports/lids created the “checker board” pattern. However, all contemporary images of the Franklin ships show that the white band corresponded with the solid chock channels grafted on to the ships. It is important to note that this paint scheme is different than that utilized during the 1839 Ross voyage, where the ships appear to have had two bands of white on the outside weather works. This watercolor of HMS Terror by Davis shows that one of the white stripes was contiguous with the chock channels, as in the 1845 expedition, while the other white stripe was a little lower, perhaps contiguous with the band of copper sheathing that extended below the chock channels for most of the ships' length at this time.
 
The colour of the top, horizontal, surface of the channel is less certain, as the Stanley watercolours provide little detail in these areas. One of Stanley’s sketches (see here) seems to indicate that the tops of the channels were black, while another suggests they were potentially white (see here). However, the famous image from the Illustrated London News clearly shows that that the top of the channels were painted white (see image above). An image of the Terror beached on the Irish Coast in 1837 by Owen Stanley (see here) also shows that the tops of the channels may have been painted white (or at least a lighter colour), though how consistently the ships were painted on subsequent voyages is unknown. Since the paint scheme is ambiguous, I intend to try both versions on the model and choose whichever seems to fit better with the overall colour scheme of the ship.
 
 
Similarly, contradictory information exists about the paint scheme on the rudder and transom of the ships. The 1845 watercolour by Owen Stanley seems to show that the transom and rudder were painted black, although the lighting effects on the painting suggest that those areas of the ships may simply be in shadow. Other contemporary sketches by Stanley and  Graham Gore (also here) suggest that a lighter colour was painted on the stern window frames and on the entire transom of the ship, while the rudder remained black (perhaps with white trim?).  The Illustrated London News image is slightly different (see above), showing a thinner arch of white surrounding the windows of the ship and a darkly painted rudder.
 
Colour paintings of the Erebus and Terror produced for the Antarctic expedition by Davis (see also here) show that the entire transom was painted white and the rudder was black, again perhaps with white trim (although lighting might play a factor here as well). Interestingly, the Davis paintings also show detail of an arch-shaped feature surrounding the windows.  Similarly, a sketch of the Terror from 1837, by Owen Stanley, indicates that the transom was painted completely white (Back 1838:400, see below).  A water colour of the Terror on the same voyage by William Smyth also shows an all white transom, this time with a white rudder.
 
 

HMS Erebus and Terror under sail . Note lighter colour of transom (Ross 1847a).
 
On balance, the available sketches and paintings suggest that the transom was painted completely white, and that the window frames were as well. The rudder is more ambiguous, but again, the weight of evidence seems to indicate that it was painted black, perhaps with white trim (the Terror did have several separate trim pieces grafted to the aft margin of the rudder).    
I assume the black hull paint extended to the keel, as we know that HMS Terror and Erebus were not coppered below the waterline, as noted in The Times on 26th April, 1845:
 
 
“The decks of the Erebus and Terror are constructed on the diagonal principle,
and about twenty feet on each side of the bows has been cased with strong sheet
iron. There is not any copper sheathing on either of the vessels, as no danger is
to be apprehended from the attacks of shellfish or barnacles, the ice soon clearing
them from encumbrances of that description.”
 
                                                     (The Times, London, 26 April 1845)
 
This is in contrast with the Illustrated London News image of the ships which appears to show a copper plated hull, which must be an error.
 
One of the things I enjoy about ship modeling is that it is woodworking – often with very fine hardwoods. Like many ship modelers, I don’t want to cover beautiful wood with paint; instead, I intend to present the Terror’s historic paint scheme using minimally treated natural or dyed/stained wood finishes. My plan is to use dyed or stained Swiss pear for the keel, stem and stern timbers, and hull planking; holly for the transom, chock, and deck planking; and yellowheart for the inside bulwarks. I’ve order the material from Hobby Mill, all planed to exact scale thicknesses, which I will discuss in future posts.  My wood arrives in early December; until then, I will keep cutting stations!
 
 
References Cited:
 
Gould, Rupert T.
1928    Oddities. Frederick A. Stokes Company, London .
 
Inglis, R.H.
1852 Vessels in the North Atlantic. House of Common Parliamentary Papers, London.
 
Konstam, A.
2010 Naval Miscellany. Osprey Publishing, Oxford.
 
 
As always, for better images please see my blog!

STATION UPDATE
 

 
Over the past several weeks, another woodworking project has kept me away from HMS Terror. However, I’ve made a little progress on preparing the bulkheads for assembly. These are made simply enough; the plans are glued directly to the plywood board using spray adhesive and then cut out using a scroll saw with a fine blade.
 
You can see from the picture that I’ve intentionally left a rough 1-2mm gap surrounding the plan outlines. It is impossible to cut the bulkheads accurately with the scroll saw, so they will be carefully reduced to the precise dimensions using a spindle sander and file. The midline slots will be cut with a coping saw and filed, again to ensure accuracy.
 
If you look closely, you can see the shrewd eye of Crozier overlooking the outfitting of his ship (he’s 1:48 scale as well).

CONSTRUCTION PLANS
 

The construction plans laid out in my small workshop.
 
While I can never be certain that my plans are precisely correct, I believe, given the available historical sources, that they represent a reasonably accurate representation of HMS Terror as she was fitted for her final 1845 voyage. Certainly, much research remains to be completed on specific details (e.g. colour scheme, masting and rigging, hardware, name and cipher(?), etc.), but now that I’m satisfied with the accuracy of the ship’s general profile and dimensions, I can move to creating construction plans for a plank on bulkhead model.
 
 
I created the plans directly from the inboard profile and body plan, using a method similar to that outlined by Rich Brayshaw. The stern configuration from the sternpost to the rudder will be recreated just as it was designed in the Terror’s 1845 stern modification plan, and the keel, false keel, stempost, stemson, and knee will be constructed in a similar manner. The false keel structure will be made from 1/4 inch (6.35 mm) plywood, which matches the exact scale width of the sternpost and keel. The slots in the false keel descend to the load waterline, and will accommodate 21 bulkheads, corresponding to each station on the plan. While this might seem overkill for a 1:48 scale model of a small ship, it will give a very solid base for the planking, and I believe it will generally result in a more accurate model. You may notice that the height of the false keel doesn’t line up exactly with the inboard profile plans; this is because I modified it to account for the deck camber (derived from the 1839 Terror and Erebus cross section plan).
 

 
The bulkheads (which represent all the stations) may seem quite unusual to those who work with plank on bulkhead models. This is because each includes a precisely faired outline of the solid chock channels that surrounded the ship. The 1839 Terror and Erebus cross section plans show that the channels actually sat on the first layer of planking, and I considered recreating this, but quickly dismissed it. My reasoning is that, after a first layer of planking, it would be very difficult to line up the channels to create a perfectly symmetrical model. As a result, I’ll apply the first layer of planking around the channels (they will actually help me align it), then plank the channels, then apply the second layer of planking (recall that both the Terror and Erebus had double deck and hull planking). The bulkheads will be cut from 5mm plywood.
 

 
There is something very tangible to me about rolling out a freshly printed sheet; the plywood is now being pressed to remove any bends and twists; cutting starts this weekend!

Further to Andy's great information, I thought it might be instructive to post this image.
 
 

 
 
Clearly a boiler explosion on one of these ships would have been catastrophic, so their installation came at some risk. Considering that the engines had already been retired from the railway, and that fresh water would have been difficult to produce on these vessels (I assume salt water would have caused corrosion), I suspect the two engineers had many challenges.

I see what you mean in your second photo. It is most likely hiding a steam safety valve (pop valve). This is a sprung valve that will lift if the boiler experiences too much pressure. I'm guessing the pipe was added to keep live steam from blasting directly into the engineer's and fireman's faces. Here's the inner workings:
 

 
In your sketch, live steam is collected in that funnel shaped pipe in the steam dome. At the base of that is the throttle valve. This is a saturated steam engine, so there is no superheater, the steam is then sent directly to the cylinders. The straight pipe coming up from the cylinders is the exhaust pipe. You can see how it narrows as it extends, but flares just before the base of the stack. By forcing the exhaust steam out at high speed (but not high pressure) it creates a vacuum in the smoke box (that's the compartment ahead of the boiler flues, the pipes leading from the firebox forward). The vacuum creates a draft drawing air from gratings under the fire bed, through the fire and forward through the boiler flues. The effect of this is creating a very hot fire. Hot fire equals more steam generated in a given amount of time equals greater speed/power from the cylinders. More modern locomotives used a small steam driven turbine to draw air when the locomotive was not being worked.
 
The other "dome" (with the lever) over the firebox is most likely part of a pump/injector system to get water into the boiler. Later locomotives do not admit cold water directly over the firebox. This is partly the reason so many early locomotives blew up. If the water in the boiler became too low and the crown sheet (top sheet) of the firebox became uncovered, a panicked injection of cold water would cause it to fracture. Steam at pressure would rupture the sheet, drastically causing the pressure in the boiler to drop, which in turn would cause any water remaining in the boiler to immediately flash into steam. Steam increases in volume 1600 times from water (at standard atmospheric pressure), considering a boiler of the size you've got, a volume of, say 1.5 to 2 tonnes, you can just imagine the effect.
 
Another thought, is it possible your engine would have been of the "Planet" type (like your picture)? They where one of the earliest locomotives produced in large numbers, starting around 1830. Even by the late 1830s they were starting to be superseded by more improved designs, which would have made some of them available on the surplus market.
 
Andy

PROOFING THE PLANS: PART II – THE LOCOMOTIVE ENGINE
 
One of the major innovations of the 1845 expedition was the conversion of HMS Terror and Erebus to auxiliary steam power (Battersby and Carney 2011).  On his blog, Peter Carney has documented his research on the locomotive engines used in this conversion; he later published his findings in the International Journal for the History of Engineering and Technology (Battersby and Carney 2011). To me, his research strongly indicates that the locomotive engines were not the Planet Type as has traditionally been assumed (e.g Cyriax 1997), but rather the Croydon and Archimedes engines built by G & J Rennie in 1838 and 1839.
 
 
Based on Carney’s research, I originally utilized a plan published in Brees (1840:133) which was labeled as the “Croydon” engine. However, in a recent email correspondence, Mr. Carney pointed out that this image was probably incorrectly attributed by Brees. The issue lies in the wheel arrangement and cylinder position. The image I based my locomotive plans on depicts a “0-4-2” engine with outside cylinders, while the Croydon was likely a “2-2-2” engine with inside cylinders (Bradley 1963; see also Carney’sblog). Mr. Carney believes the image I based my plans on probably depicted the “Hercules” engine, which was an assistant engine while the Croydon and Archimedes where passenger locomotives.
 
 
I always suspected there was something wrong with the locomotive I used in my original plans. If you look at my previous profile plans, the cylinders actually overlap the position of the spare rudder. Given that the modifications to the 1836 Terror plans show the exact position of the new engine room walls, this obviously could not have been the locomotive installed in 1845 (i.e. the locomotive was simply too big). Mr. Carney kindly pointed me to another image drawn by Brees (1840:306) which is unnamed, but which depicts a 2-2-2 locomotive with inside cylinders that was built by G & J Rennie – a good candidate for Croydon or Archimedes.
 
 
Using this new plan and an excellent set of drawings that Mr. Carney created and kindly provided (see his 3D reconstruction), I created my own scale plans of the locomotive. Using the dimensions from Bree’s (1840:14) original report, I scaled this new plan to exactly 1:48 and placed it in the proper position. As you can see, it fits perfectly, with just inches to spare on either side of the engine. To me, this exact spatial correspondence just adds credence to Carney’s theory that Archimedes or Croydon was the locomotive installed on HMS Terror.  
 

My new plans of the G & J Rennie engine, based on Brees (1840:306),
following the research of Peter Carney. The frame is speculative.
 
 

INCORRECT - My original plan using the Hercules (?) engine. Note
the overlap with the spare rudder.
 
 

CORRECT? - The new engine in my updated plans.
 
 
Because of the new locomotive engine, the position of the funnel and steam outlet changed significantly, and these are depicted on the new deck plans. Given that the locomotive was only used in calm conditions or to avoid beating, it is likely that the chimney and steam pipe were removable, to conserve space on the crowded deck (Battersby and Carney 2011:202). As a result, I believe a scuttle or hatch system was used when the chimney was not installed, and I based these on one shown in the 1836 Terror deck plans (I have been unable to determine what that 1836 hatch was originally used for – the furnace chimney was apparently installed at the fore hatchway).
 

The positions of the chimney, steam pipe, and their hatches on my old plans.
 

The positions of the chimney, steam pipe, and their hatches on my new plans.
 
Finally, I should note that on my plans the height of the engine’s chimney and steam pipe are based on the following contemporary description (which also accurately describes the location of the chimney and the steam pipe (Anonymous 1845):  
 

 
*  Note: Rather than post yet another set of updated plans, I’ve simply updated the plans on a previous blog post. The images have begun to be indexed on search engines and I don’t want to create confusion!
 
 
* For better images please see my blog!
 
References:
 
 
Anonymous,
1845    Literary Gazette Journal for the Year 1845. Robson, Levey, and Franklyn, London.
 
Battersby, William, and Carney, Peter
2011    Equipping HM Ships Erebus and Terror, 1845. International Journal for the History of Engineering & Technology 81(2):192-211.
 
Bradley, D.L.
1963    Locomotives of the South Eastern Railway. Solihull: Railway Correspondence and Travel Society (1):11–12.
 
Cyriax, Richard, J.
1997   Sir John Franklin's Last Arctic Expedition: The Franklin Expedition, A Chapter in the History of the Royal Navy. The Arctic Press, West Sussex.
 
 
 
 
 
 
 
 
 
 
 
 

PROOFING THE PLANS: PART 1 - CONTEMPORARY IMAGES
 
 
 
Over the past several months I’ve received some great feedback on my research into HMS Terror from the model shipwrights on Model Ship World. However, before finalizing the construction sheets, I felt that that it was important to ask the opinion of some Franklin expedition historians.
 
A few weeks ago, I took the opportunity to contact two of the most knowledgeable experts on HMS Erebus and Terror, William Battersby and Peter Carney. Both maintain their own blogs and have published on the ships in peer-reviewed journals (Battersby and Carney 2011). Moreover, both are true gentlemen; they kindly took the time to read through my blog and offered some very useful advice on my plans.
 
Mr. Battersby suggested that I look again at a drawing from the Illustrated London News (ILN) which depicts Franklin’s cabin on HMS Erebus. He pointed out that there appeared to be a cabin stove with a straight chimney on the extreme left of the image, which I did not include in my plans. The image seems reasonably accurate; the number and position of the windows and the shape and size of the stern lockers and superstructure matches the 1839 plans perfectly. As a result, I’ve modified my plans to include this stove; I based its dimensions and shape on what can be deduced from the image. The chimney for the stove is based on an 1839 image of a cabin stove available from the National Maritime Museum archive, and the height of the chimney is based on tables from Lavery (1987:291). Incidentally, the height of the chimneys for the ship’s stove and furnace are based on information in Lavery’s book as well.
 

Cabin stove and chimney detail.
 
Mr. Battersby also reminded me that a (very early) 1845 daguerreotype image of one Franklin’s officers, Lt. Henry Le Vesconte, was taken on the deck of HMS Erebus. I’ve scrutinized it many times before and it’s a remarkable image which should be included in any thread about the ships. Le Vesconte is sitting on the starboard side of the Erebus (note the image is often shown backwards) next to the compass table in front of the mizzen mast. The photo confirms that the position and design of the skylight, mast, and wheel remain unchanged from the 1839 plans, and may also show part of a small deck house further aft on the starboard side (it appears to have a black door).
 
Mr. Carney also provided some extremely helpful insights. He pointed out that another image from the ILN shows two white deckhouses at the stern of both ships (note they also have black doors, just as in the Le Vesconte image). These were most likely water closets and signal lockers, and in my original plans I kept these quite low (almost the height of the bulwarks), based on an 1845 image of Erebus drawn by Owen Stanley. However the perspective used in his sketch probably foreshortens the height of the deckhouse and is not a reliable guide. 
 

 
Following the ILN image, I modified the deckhouses to be the same height and size as the single deck house depicted in the 1839 plans. It is unknown if both were water closets or if one was a locker of some sort, so, in keeping with the original 1836 and 1839 plans, I am assuming that only one water closet was built for this voyage (only one water closet was used on Terror’s first two voyages, and the Terror had roughly the same crew compliment on all three polar voyages). I placed the water closet on the starboard side, following the suggestion of Battersby and Carney (2011:204) and based its design on the 1839 plans. I turned the other deckhouse into a locker for signal flags and other equipment and I admit its interior design is entirely speculative. Regardless, the model will have single black doors facing forward as is displayed on the ILN image (and which appears to be shown in the Le Vesconte daguerreotype). I should also note that both HMS Investigator and HMS Enterprise (1848 Franklin search vessels) shared many design similarities with the Franklin ships and both had twin deckhouses roughly the same size and shape as I have shown on my plans. In fact, both of their deck plans show the water closet on the starboard side of the vessel.
 

The new deckhouse profile, based on the 1839 plans.
 

Detail of stern water closet and signal lockers.
 
 
I should note that Peter Carney has also produced an excellent 3D model of James Fitzjames’ cabin, based on another contemporary image from the ILN. I did not include this structure in my plans as it was never depicted in any of the profile sheets (it is shown on the deck plans).
 
Finally, I should note that the daguerreotype discussed above isn’t the only one that might show part of the ships. Russell Potter, another Franklin blogger, has written some very interesting posts about the reflections in the highly polished caps of the Royal Navy officers, which show the rigging and perhaps the position of one of the ship’s boats.
 
*  Note: Rather than post yet another set of updated plans, I’ve simply updated the plans on the previous post. The images have begun to be indexed on search engines and I don’t want to create confusion!
 
References:
Battersby, William, and Carney, Peter
2011    Equipping HM Ships Erebus and Terror, 1845. International Journal for the History of Engineering & Technology 81(2):192-211.
 
Lavery, Brian
1987    The Arming and Fitting of English Ships of War, 1600-1815. Conway Maritime Press, London.
 
 

Hi Mark,
 
Druxey is correct. The prop shaft was simply extended when the propeller was shipped. I'm not certain what sort of coupling was used on Terror (it's not discussed in any literature that I could find), but Battersby and Carney suggest it might have been a "telescoping coupling" similar to that installed on HMS Ajax in 1846. You may want to consult Bourne's A Treatise on the Screw Propeller (1855). The document has several very detailed drawings of raising propeller frames and couplings.  None of these perfectly matches the configuration shown in the plans of HMS Terror, but several are very similar (see here and here). The book is available for free on Google Books.
 
Thanks for the interest - I always enjoy these questions because they force me to think of things I haven't thought of before (i.e. how do I model the shaft and coupling?). Also, the original plans, which I have replicated almost precisely in my plans (warts and all), clearly simplify many details. I'll be using sources like Bourne's  to add all those little details when I build the model. Should I transfer those details to the plans? I probably won't - I want them to be clearly based on the originals, even if I'm altering them to create the vessel as fitted in 1845.  But I'll discuss them here, of course!
 
Cheers,
 
E&T

HMS TERROR PLANS – UPDATED!!
 
As discussed in the previous post, here are the updated (hopefully complete?) plans for HMS Terror. Note that the Upper Deck Plan has been modified to include the accurate width of the propeller well, based on information gleaned from the engineer’s model. Also, I noticed that the model showed a narrow lip surrounding three sides of the well for the scuttle to rest on, so that has been included in the plans as well.
 

 

 

Over the past couple of weeks I’ve been designing construction plans for my model (I hope to begin cutting wood next week). As I worked on individual stern components, I began to notice possible errors in my plans. Specifically, the original 1845 stern sheet (and the annotations on the 1836 sheet), on which my plans are based, only exist in profile and therefore don’t depicted all the necessary cross-sectional modifications to the stern that were required. The problem lies exclusively in the well that was constructed to ship and unship the auxiliary screw propeller. If the rudder post (also known as the “false sternpost” or “after sternpost”) was the same width as the sternpost depicted in Terror’s original 1813 plans, there simply would not be enough space for the propeller well positioned directly in front of it. I strongly suspected that the rudder post was thicker than I originally depicted in the body plan (and thicker than the keel), but there were no historical plans that confirmed this. Fortunately, an engineering model of the modified stern was produced for the Erebus and Terror ca. 1845.
 
As can be seen on the model, the upper part of the rudder post was indeed widened, apparently by adding two large bolsters on either side; it then tapered abruptly at the opening for the propeller (likely to prevent drag). The added width on the upper part of the rudder post provided the necessary space for the propeller well and I’ve now changed my body plan to reflect this. However, in scrutinizing the stern plans and annotations to solve the width problem, I also noticed some faint modifications that I missed in my initial tracing of the plans.
 
First, the opening for the propeller well apparently included two separate iron fittings which were bolted to the rudder post and the sternpost, respectively. Each fitting appears to have had a groove which accepted a smaller rectangular metal frame which held the propeller (e.g. Battersby and Carney 2011: 204; 208). Guided by the metal grooves, the propeller frame could be raised or lowered into position using standard ship’s tackle. A contemporary example of exactly this sort of removable propeller system is preserved in a model at the National Maritime Museum in Greenwich (see here and here for similar designs).
 

My reconstruction of the propeller frame and chock system (profile and cross section).
The series of chocks were used to strengthen and protect the stern when the propeller was unshipped

 
 

The propeller frame as it would have been installed
 
Second, it appears that a unique u-shaped iron fitting, the same length as the propeller well, was used to secure the sternpost, keel, and rudder post to each other. Two or three large bolts secured a separate timber to each of the three faces of the fitting, effectively creating one solid structure. I suspect that this was a midline fitting which was protected and covered by a large fitted wooden chock, which itself was bolted to the surrounding wood, probably with as many as four bolts. Why this unique fitting was necessary has not been described in the historic literature, but is seems certain it was used to increase the strength of the sternpost near the keel (recall that Back’s voyage proved how vulnerable an unmodified stern could be to pack ice). How the ship’s stern timbers were attached to this structure is also not described, but it seems logical that the rudder post and sternpost would have been bolted to the two central stern timbers, with which the widened sternpost would have been contiguous. Contemporary models show that a sturdy rectangular frame enclosed similar contemporary propeller wells, and the sternpost and rudder post were also bolted to this frame.
 


The "U" shaped bracket and series of bolts used to attach the rudder post and sternpost to each other and the keel.
 
 
References:
Battersby, William, and Carney, Peter
2011 Equipping HM Ships Erebus and Terror, 1845. International Journal for the History of Engineering & Technology 81(2):192-211.
 
As always, please see my blog for better images.

HMS TERROR, 1845, UPPER DECK PLAN (AS FITTED)
 
The last technical plan required for HMS Terror is the upper deck, which I have finally completed.
 

Please note: This plan has been updated - please consult my later posts.
                                                                                           
The original 1836 and 1839 deck plans for HMS Terror show the outlines of the ship with planking installed. Therefore, on my plans, I have included the outline of the frames as well as the planking to better facilitate construction. Like the original plans, the position of the solid chock channels accounts for tumblehome. Because the 1839 plans depict HMS Erebus, my plans are based on the 1836 upper deck plans for HMS Terror, but the deck furniture is the same type and style as depicted on the 1839 sheets (see previous posts for rationale). Similar to the profile plans, the position of the deck furniture is based on the 1836 sheets.
 
The most substantial modifications to the plans are at the stern - to accommodate the new position of the rudder and the well for the screw propeller. As a result, the central structure on the stern containing the cistern, color boxes, and water closet was removed from these plans (presumably these were moved to the position of one of the chicken coops). These modifications are also depicted in a contemporary image of the Erebus drawn by Owen Stanley, which shows two large structures on either side of the vessel at the stern.
 
The deck planking on the vessels was unusual and was not depicted in any contemporary plans. Rice (Ross 1847), the shipwright responsible for the refitting, described them in detail:
 

 
A contemporary model of HMS Erebus displays that the upper layer of deck planking angled outwards and forwards from the central planks towards the bulwarks. This style was also used for the upper deck of HMS Investigator, which searched for the Franklin vessels on two voyages between 1848-1853. Investigator’s upper deck plan shows that the planking was placed on an angle about 45 degrees from the centerline. On my plans, the width of the central planks is based on the 1839 midships cross section, but the width of outer planks is not described in any contemporary sources and required more research. Fortunately, an archaeologist at the Canadian Museum of Civilization, has recently identified a piece of 3 inch thick “fir” deck planking that she demonstrates is very likely to be from one of the vessels (if so it is the only piece of the ships known to currently exist). The plank is exactly 7 inches wide; therefore this is the dimension I use on my plans. 
 
References:
Ross, Sir James Clark
1847    A Voyage of Discovery and Research in the Southern and Antarctic Regions, During the Years 1839-1843: Volume I. John Murray, London.
 
As always, please see my blog for better images.

HMS Terror, 1845, Inboard profile (as Fitted)
 
My plans from the 1845 inboard profile of HMS Terror incorporate all of the information presented in my previous post (as well as information to be presented in subsequent posts). It represents nearly a year of research, and no doubt contains unknown errors. Despite the fact that my model won’t show any detail between decks (I intend to build a plank on bulkhead model), I felt the inboard profile would be incomplete without these details.
 

Please note: This plan has been updated - please consult my later posts.
 
 
As always, for better images please see my blog!

DESIGN INFERENCES
A significant quantity of historic source material, including original Royal Navy plans, exploration accounts, news reports, and personal letters, sketches, and drawings exist which document the final 1845 configuration of HMS Terror. Creating an accurate plan for the ship requires carefully parsing these data and drawing inferences about the ship’s probable appearance. Below, I outline the rationale behind my reconstruction of major aspects of the Terror’s final 1845 design, as fitted. This is not an exhaustive account, and specific topics such as the locomotive engines, funnel and chimney sizes and positions, propellers, cipher and name, and paint scheme will be discussed in later posts.

Bow/Stern Shape:
As described previously, the 1839 plans depict HMS Erebus, and therefore the 1836 profile must provide the basis for the bow design of the Terror, which is substantially different from the 1813 profile. It is uncertain if the 1836 refit resulted in modification of the cant frames, but Rice (Ross 1847a) appears to indicate that bolsters were added to the exterior of the frames to change the line of the bow.




In my plans, the stern configuration and framing is exactly as depicted in the 1845 annotations (in green ink) of the 1836 profile, which were made to accommodate the auxiliary screw propeller.

Keel, False Keel, and Stem:
The position and configuration of the keel is based on the 1813 inboard profile. The stempost configuration is based in the 1836 inboard profile, but lengthened slightly to accommodate the new position of the bowsprit as shown in the 1845 alterations (in green ink). I should note that a faint pencil modification in the 1813 inboard profile of  HMS Vesuvius also appears to depict the outline of the stempost as drawn in the 1836 Terror profile. The scarph joints on the stempost are based on the 1813 profile, or based on standard designs for the era (e.g. Goodwin 1987:29).

Keelson and Stemson:
The keelson and stemson designs are based on the 1813 profile, but with alterations at the stern to be consistent with the 1845 annotation (in green ink) of the 1836 inboard profile. The bolstering and riders added above the stemson are based on the 1836 inboard profile plans.

Deadwood, Rising Wood, and Knee:
The bow and stern deadwood configurations are not documented in any of the Admiralty plans. Interestingly, the 1813 plans indicate that HMS Terror utilized an older stemson design than the era in which it was built; therefore, the in my plans the deadwood configuration is based on a style in use ca. 1800 (Goodwin 1987:29). The rising wood configuration at the bow is based on the 1813 profile which is partially complete, with information drawn from standard styles utilized in the early 19th century (Goodwin 1987:29).The knee of the Terror was essentially removed (as discussed by Rice [Ross 1847a]), and was replaced with a highly reduced and simplified knee that projected only enough to support the bowsprit. The knee configuration in my plans is based on the 1836 profile, lengthened to support the new position of the bowsprit as depicted in the 1845 annotations on that plan. The joints for the knee (i.e. the configuration of the gripe and bobstay pieces) are based on standard conventions for the period (e.g. Goodwin 1987:37).

Rabbet Line:
Because of the lengthening of the bow and the reduction in the knee, the Terror’s rabbet line must have been highly unusual. The model of HMS Erebus at the National Maritime Museum indicates that the knee (much of which was covered in plating) was essentially flush with the hull planking at the bow. No rabbet is depicted in the 1836 plans of the Terror, so at the bow I based in on the on the thickness of planking as depicted in the 1839 midships section, with the goal of keeping the hull planking below the chock channels (and excluding the wale) flush with the knee. Closer to the keel, the rabbet line recedes until to meets the original rabbet line depicted in the 1813 profile. The rabbet on the keel is based on the line depicted in the 1813 profile. The rabbet at the stern was easily deduced from the 1845 plan of the modified stern, which clearly displays where the hull planking terminates.

Bow Plating:
The position and size of the iron bow plating are based on the 1845 annotation (in green ink) on the 1836 profile. This annotation indicates that iron plating was more extensive than the cross-shaped copper plating used for the 1836 Back Expedition, but did not extend along the waterline like the copper plating utilized for the Antarctic Expedition (depicted in the 1839 profile).

Deck Fittings:
All deck fittings for my plans are based on the 1839 inboard profile of the Terror and Erebus (see a previous post for the discussion of the Royal Navy’s policy of identically outfitting exploration vessels). As discussed previously, the 1839 plans depict the Erebus, so the positioning of the furniture, masts, and other deck fittings are based on the 1836 Terror profile. The position and size of the ship’s boats are based on the 1839 plans (Terror’s boat positions are depicted in red ink), with slight modifications to accommodate the different positions of deck fittings on HMS Terror.

Deck Placement and Wall Partitions:
The 1845 annotations (in green ink) of the 1836 Terror profile appear to contain errors. Specifically, the placement of the decks match the 1845 stern modification plans perfectly, but do not match the position of the decks in the 1836 inboard profile. However, the drawn position of the walls and deck partitions of the 1845 modifications (in green ink) do match the 1836 and 1813 plans precisely, or make logical accommodations for new equipment (e.g. the locomotive). This would suggest that the 1845 annotations based on the stern redesign were simply copied to the plans and not specifically adapted for HMS Terror. Thus, in my plans the position the wall partitions correspond with the 1845 annotations and unmodified 1836 plans, but the position of the decks are depicted as in the 1836 plans. The construction of the upper decks (doubling) corresponds to the 1839 and 1836 inboard profiles.

Bulwarks:
All the plans are inconsistent regarding the height of the Terror’s bulwarks. As described in a previous post, the 1839 Inboard profile is obviously meant to depict the Erebus (the bulwarks would be over ten feet high if placed in this position on the Terror). The 1845 annotations (in green ink) on the 1836 inboard profile likely reflect the proper position at the stern, but do not extend all the way to the bow and appear to be drawn at an inappropriate angle (possibly because it was directly copied from the 1845 stern modifications). To rectify this issue, I traced the cap rail of the 1836 plans and then raised it into position to match the stern location of the cap rail depicted in the 1845 modifications (in green ink). The bulwark lines were then extended at the bow to intersect this new cap rail position. Interestingly, this new position appears to match a pencil line marked on the plan of HMS Vesuvius. This, combined with the annotations to the stempost, strongly suggests that the pencil lines on HMS Vesuvius plans were meant to depict modifications to HMS Terror. This makes some sense; by 1845 the 1836 Terror profile was so densely annotated that that a new sheet may have been required (HMS Vesuvius was identical to HMS Terror and HMS Beelzebub).

Rudder:
The internal construction of the rudder is based on the 1836 profile, but its size, shape, position, and hardware are based on the 1845 stern plans and the corresponding annotations on the 1836 plans (in green ink).

Solid Chock Channels:
The 1836 plans for HMS Terror show a large gap, roughly amidships, in the solid chock channels, and this is confirmed by contemporary paintings by Owen Stanley. As described by Rice (Ross 1847a), in 1839'continuous solid chock channels were constructed on both Erebus and Terror and are shown in the 1839 profiles and deck plans representing both ships. All contemporary 1845 paintings/drawings of the Terror depict solid chock channels surrounding the ship; therefore, a solid chock channel consistent with the 1839 profile is utilized for my plans.

Mast Positions and Rake:
The mast position and rake are based on the 1836 inboard profile (which, as described previously, differs from the 1813 profile). Configurations of the mast steps and their method of attachment are based on the 1813 plans (mizzenmast) and 1836 plans (foremast and mainmast), but the taper of the masts (not depicted in either the 1813 of 1836 plans) is based on the 1839 plans.

Windows:
HMS Terror was originally designed with five stern windows, and drawings by Own Stanley made during Back’s 1836 voyage indicate that each had six panes. However, the central window was removed during the 1845 refit to make room for the new propeller well and the new rudder position, a modification corroborated by the drawings of Stanely, Gore, and others.



Owen Stanley 1845 "Parting company with Terror, 4 June 1845", Courtesy National Library of Australia

An engraving of Franklin’s cabin published in 1845 by the Illustrated London News shows that the windows each had four large panes (probably double-paned) with very robust sills and muntins.



Planks:
As the 1839 midships cross section indicates, the hull planks range in width from 8 inches on most areas of the hull to more than 10 inches (average) at the wales. This is corroborated by the 1845 stern plan which depicts hull planking averaging about 9 inches in width. However, it should be noted that the 1845 stern plan displays that the planks were carefully spiled with no drop planks, so it can be expected that plank widths would vary significantly beyond the average width. In my plans of HMS Terror, all hull planks aim for an average width of ca. 9 inches. The wale planks have a maximum width of ca. 14 inches at the touch, narrowing to ca. 7 inches at the butts. The wale planks are based on the hook and butt design used for bomb vessels as depicted by Goodwin (1989), a planking system which was also commonly used on polar exploration vessels and other sturdy craft (Ware 1991).

References:
Goodwin, Peter
1987 The Construction and Fitting of the Sailing Man of War. Conway Maritime Press, London.

1989 The Bomb Vessel Granado 1742. Naval Institute Press, Annapolis.

Ross, Sir James Clark
1847 A Voyage of Discovery and Research in the Southern and Antarctic Regions, During the Years 1839-1843: Volume I. John Murray, London.

Ware, Chris.
1991 The Bomb Vessel: Shore Bombardment Ships of the Age of Sail. Naval Institute Press, Annapolis.

As always, for better images please see my blog!

TERROR MODIFIED: THE HISTORIC PLANS (Part 3)
 
1845 Sheets
The ships were again extensively refitted in 1845 to convert them to auxiliary steam propulsion, a modification deemed necessary to save precious time during the ice-free season “providing the wind should prove contrary or a dead calm”.  An excellent plan of the stern modifications exists (from which the preceding quote was drawn), which displays the complete redesign of the Terror’s stern. These exact plans are reproduced in green ink on the 1836 plans of HMS Terror, indicating that the ship was shortened at the position of the lower and upper decks, but the sternpost was moved aft to provide room from the new screw propeller. Above the screw propeller a massive well was constructed through which it could be easily shipped and unshipped. When the screw was not in use, the well was filled with a series of solid wood and metal chocks to add strength to the vessel’s stern.
 
The 1836 inboard profile of the Terror depicts that partitions on the orlop deck and in the hold were modified to accommodate the new propulsion system, which was an unmodified steam locomotive engine, anchored just aft of the mainmast. Much speculation has occurred about the type of engines utilized, but recent research by Peter Carney (see Battersby and Carney 2011:203) argues that the locomotive was the Croydon/Archimedes type, for which partial plans exist (Brees 1840). If these were the engines installed in the Terror and Erebus, they were an excellent choice, as they were known to be exceptionally reliable (Brees 1859:90):
 

 
Green-ink modifications to the 1836 inboard profile also display that the extensive copper plating was removed in favor of thicker iron plating which covered the entire bow and extended ca.  15 feet aft. The plans also indicate that the Terror’s bowsprit was raised by approximately 4.5 feet; the reason for this is unclear, but the Terror had a much shallower draught than the Erebus and given her sailing qualities, this modification was likely necessary. Further alternations to the partitions of the decks are depicted (in green ink) in both the 1836 and 1839 plans, the most significant of which appears to be the extension of the watertight bulkhead system forward, which must have resulted in a significant reduction in hold capacity.
 

 

OwenStanley, 1845, " Departure of H.M.S. Erebus and Terror for the North Pole,1845", courtesy National Library of Australia.
 
 
References:
 
Battersby, William, and Carney, Peter
2011    Equipping HM Ships Erebus and Terror, 1845. International Journal for the History of Engineering & Technology 81(2):192-211.
 
Brees, S.C.
1840    Second Series of Railway Practice: A Collection of Working Plans and Practical Details of Construction in the Public Works of the Most Celebrated Engineers. John Williams, London. 
 
1859     Railway Practice: A Collection of Working Plans and Practical Details of Construction in the Public Works of the Most Celebrated Engineers. R. Griffin and Co., London.
 
 
As always, for better images please see my blog!

TERROR MODIFIED: THE HISTORIC PLANS (Part 2)
  1839 Sheets
The Terror was again extensively refitted for the 1839-1843 Ross Expedition. Some of these modifications, such as the change to a forced air heating system and the extension of a ring of solid chock channels around the entire ship, were obviously a direct result of lessons learned from the 1836/37 Back Expedition. However, many of the 1839 modifications resulted from a process of standardization with her sister hip, HMS Erebus. This was based on Sir Edward Parry’s longstanding policy of outfitting exploration fleets with identical equipment, the rationale being that one vessel’s fittings could be used to repair another in the case of catastrophe (Battersby and Carney 2011:203).  Rice, the shipwright in charge of the 1839 refit, provides an excellent description of the modifications done to the ships at this time, and it is worth noting here in its entirety (Ross 1847).
 

 


 
The 1839 plans illustrate the inboard profile and all decks, although the Terror’s modified lines are not represented. All sheets are labeled “Terror and Erebus”, reflecting both the similar design of the ships and the identical manner in which they were outfitted. Uniquely, the 1839 plans provide a midships cross section which depicts the planking configuration, the dimensions (thickens and widths) of the planks, and the position and construction of the watertight bulkheads, as well as other inboard details.

Comparing these plans to the Terror’s 1813 and 1836 configuration clearly indicates that the 1839 sheets depict the Erebus. By this time the ships were almost identical in length and had very similar lines, but the draught and breadth of the Erebus were still greater than the Terror and this is reflected in the inboard profile, midships section, and lower deck plans. Furthermore, the upper deck plans included dashed red lines depicting alternate positions of ship’s boats, labeled “Terror”, implying that the plans depict the Erebus. A noteworthy exception to this exists with the midships section; while the frames drawn match the contours and dimensions of the Erebus in breadth, the height/draught of the decks and bulwarks appear to be based on HMS Terror’s dimensions. It seems likely that this was an error on the part of the draughtsperson, who must have been working from multiple reference sheets depicting multiple vessels.

The 1839 modifications included a series of diagonal iron riders bolted to the frames in the midsection, with iron crutches and sleepers at the bow and stern to increase strength. Fewer, but larger, iron storage tanks were placed in the hold (reduced from 47 to 22), though the available historical record is mute on the rationale for this change. The unreliable hot water heating system was replaced with a much larger and more reliable “Sylverster’s Patent” hot air heating system, which would remain onboard for the subsequent 1845 voyage (Battersby and Carney 2011:200). Finally, the copper bow sheeting was also extended along the side of the ship below the solid chock channels.

It is important to reiterate that the 1839 plans introduce a critical fact; despite proportional differences in size, the ships were fitted-out in an identical fashion. Indeed, contemporary accounts outline the similarity of vessels (Anonymous 1839:405).
 
 


 
Besides the unseen internal framing and architecture, the only significant difference between the Terror and Erebus was one of proportion; reflected in the alternate positions of fittings and furniture, such as hatchways, masts, capstans pumps, etc. to account for the difference in size of the vessels. This has obvious implications for model building, as it implies that the 1839 plans, though based on the flagship Erebus, are likely to be largely applicable to the Terror. 
 
 
References:

Anonymous
1839   The Antarctic Expedition. Gentleman’s Magazine 12:405-407.

Battersby, William, and Carney, Peter 2011    Equipping HM Ships Erebus and Terror, 1845. International Journal for the History of Engineering & Technology 81(2):192-211.

Ross, Sir James Clark
1847    A Voyage of Discovery and Research in the Southern and Antarctic Regions, During the Years 1839-1843: Volume I. John Murray, London.