Iron Mast Cap Orientations in Steam/Sailing Ships

[BANYAN]

Hi folks, I am trying to determine the orientation of the iron mast caps in steam/sail screw vessels (mid-19th century).  I have established the form/construction of these from contemporary authors, but they are shy in stating whether the cap was placed horizontal (parallel with the tops to the waterline) or perpendicular to the masts?  The imagery does not clearly show one or other in the two lithographs and single photo of the ship, as in some instances they look parallel and in other perpendicular.  

 

Either form is easily made as the fittings will have been cast.  Even with the severe rake of 'Victoria's' masts (5/10/15 degrees for the fore, main and mizen respectively), the angular displacement within the cap could have been cast once the dimensions were determined.  The following show the two options (images used with permission) and I seem to recall one author saying perpendicular, but it does just not look right?   The protruding lugs at the rear hold a roller for the topmast forestay next abaft.  If horizontal is correct, its position has to be lowered a little as the imagery shows a couple of inches of the squared mast head protruding.

 

I would greatly appreciate the 'correct steer' on this, preferably with some evidence so that I can cite it), but any suggestions are most welcome.

 

cheers

 

Pat

 

[Keith Black]

 Pat, every mast component image I've seen shows the caps 90 degrees to the mast and that's the way I made mine. I can't point you to anything definitive, sorry. Hoping you find the answer you need. 

[BANYAN]

Thanks Keith, so it is one vote to the perpendicular to the mast (option 2 above).

 

cheers

 

Pat

[mtaylor]

Relooking at those photos... I'd have to go with what Keith says.  The idea of the one on the left just hits me wrong as the iron would only make full contact at the side of the masting but not the fore or aft side.  I think that would create some wear/tear/stress isseds.

[BANYAN]

Thanks Mark, actually, the attached might shed better light on the internal arrangement which shows the holes for accepting the spars angled to the appropriate rake?  This is for the Mizen which has the greatest rake and as you can see, the mast would still get full support.  These would have been cast parts so the complexity would not have been an issue, I think.  But I would tend to agree that most are shown at 90 degrees/perpendicular to the mast axis - it just sort of looks wrong on such highly raked spars.

 

My real issue with the left (drawing version) is how they will have press-fitted the iron cap on at such an angle - which sort of drives me to the perpendicular anyway.

 

cheers

 

Pat

 

Edited January 6, 2023 by BANYAN

[rwiederrich]

Personally...my experience  shows that the cap of the doubling nearly always is parallel with the deck and the mast tops.  This *rule* does have its exceptions...namely on schooners(Baltimore clippers and smaller craft, which do not have tops where men may have to work.

Also one must not forego the notion of functional aesthetics and just plain preference of the captain and or designer.  The function of the cap is not compromised either way.  But appearances make a very big difference.

A cap is almost never perpendicular to the mast axis if a top is just below it.  From my experience they are parallel to one another and the deck.  It makes for a much cleaner sight line.

 

My 5 cents.

 

Rob

 

[michaelpsutton2]

I have seen them both ways. You can look on the internet but just a word of caution... only consider actual original plans, discard modern reconstructions and model plans. They could lead you astray.

Edited January 9, 2023 by michaelpsutton2

[BANYAN]

Thanks Michael.   I have been doing that over the past few days and also trawling through the various authors (especially naval architects).  It is unusual that most are shy on discussing this.  To date, I have established that only a few make the statement that the tops were set "horizontally" but do not specify whether horizontal to deck, waterline or to xxxx.   None mention the cap orientation at all.  I am putting something together which summarises all this research which I hope to post in a day or two.  In the meantime, I will keep looking.

 

cheers, and appreciate the feedback.

 

Pat

[rwiederrich]

1 hour ago, BANYAN said:

Thanks Michael.   I have been doing that over the past few days and also trawling through the various authors (especially naval architects).  It is unusual that most are shy on discussing this.  To date, I have established that only a few make the statement that the tops were set "horizontally" but do not specify whether horizontal to deck, waterline or to xxxx.   None mention the cap orientation at all.  I am putting something together which summarises all this research which I hope to post in a day or two.  In the meantime, I will keep looking.

 

cheers, and appreciate the feedback.

 

Pat

Pat……good research can pay off.  
I hope my earlier comment didn’t appear too off center.    Maybe I failed to be clear. 
 

Rob

[BANYAN]

Thanks Rob, appreciate your input.  I have been trawling through the NMM, Danish Digital Museum etc at plans/drawings for contemporary vessels to try and get a handle on this.  I have also been scanning through Nares, Kipping, Fincham and other authors who do not give very much info on the alignment of the caps, and very little on the alignment of the tops.   Lees bases his on the models and drawings of his period of interest so nothing conclusive.  The best they have to offer on the tops is that they were placed horizontally - but horizontal to what?  Perpendicular to the mast or parallel to the waterline? 

 

I will post a summary of my findings later this week showing what I have found, and if anyone could contribute to that it would greatly appreciated.  I accept that aesthetics is also a contributing factor, but I also have to allow for working practicality, strength of the fitting, and of the attached fittings (such as the lead and strength of the roller abaft the cap), etc as you have suggested.

 

Thanks again for your feedback/suggestions which are always gratefully accepted - sorry I missed your earlier response ( I'll blame the lethargy inmduced from the New Year celebrations  .

 

cheers

 

Pat

[BANYAN]

As stated above, here is a summary of what I have found so far.  I still find it very strange that the contemporary authors did not cover this subject in any greater detail; especially in the books on Naval Architecture.

 

I would greatly appreciate further comment based on the attached pdf.  As the model is depicted circa 1861, it is right on the cusp of when the masts were replaced (as shown in the photograph - see pdf) so it could have followed either syle of heavy or light mast caps as depicted on build or in the photograph.

 

Many thanks for your interest and suggestions.

 

cheers

 

Pat

Cap and Top Alignment Issues.pdf

Edited January 12, 2023 by BANYAN

[Keith Black]

 Pat, thank you but this has left me confused to say the least. How do you build a ship with the tops and caps parallel to the waterline regardless of the rake? This makes no sense to me. A small degree of rake in the fore and main ( I set the rake on all my mast for the Tennessee at three degrees) wouldn't be noticeable but a heavy rake on the mizzen of seven degrees or more would be noticeable. Setting different rakes for different mast (from what I've read this was a common practice) means not all the mast tops and caps are going to be parallel to the waterline.

 

 This makes my ole head wanna explode like a Gallagher watermelon. 

[rwiederrich]

8 hours ago, BANYAN said:

As stated above, here is a summary of what I have found so far.  I still find it very strange that the contemporary authors did not cover this subject in any greater detail; especially in the books on Naval Architecture.

 

I would greatly appreciate further comment based on the attached pdf.  As the model is depicted circa 1861, it is right on the cusp of when the masts were replaced (as shown in the photograph - see pdf) so it could have followed either syle of heavy or light mast caps as depicted on build or in the photograph.

 

Many thanks for your interest and suggestions.

 

cheers

 

Pat

Cap and Top Alignment Issues.pdf 646.74 kB · 6 downloads

One particular fact not readily discussed, is General symmetry and balance.  It was a common practice for designers and even captains(because they often were the building Forman in charge of a vessel they would command, to make design decisions based on their own preferences, whims, or artistic/symmetrical leanings.

Parts (fixtures) of the vessel were used to measure out other parts (fixtures.  At times the main yards lengths were determined by the length of the lower main mast (deck to cap), or the jibboom as it extended past the bowsprit was twice the length of the bowsprit. So many more examples could be sighted, if one had the desire to know.

The tops were always parallel to the waterline...most likely due to the fact men would be traversing it and if it cantered at the rake of the mast....could prove to be a danger to men.  Not forgoing that it would be quite unsymmetrical.  Likewise, in most cases the cap would follow the same symmetrical principal....establishing a clean symmetrical sightline.  Yes there are always exceptions to every rule...if violating that rule does not compromise structural integrity.  In MHO.....it is more preferable to keep the caps/tops/waterline parallel. 

 

What does imagery of your vessel show you?

 

Rob

[Snug Harbor Johnny]

8 hours ago, Keith Black said:

 Pat, thank you but this has left me confused to say the least. How do you build a ship with the tops and caps parallel to the waterline regardless of the rake? This makes no sense to me. A small degree of rake in the fore and main ( I set the rake on all my mast for the Tennessee at three degrees) wouldn't be noticeable but a heavy rake on the mizzen of seven degrees or more would be noticeable. Setting different rakes for different mast (from what I've read this was a common practice) means not all the mast tops and caps are going to be parallel to the waterline.

 

 This makes my ole head wanna explode like a Gallagher watermelon. 

   'Could be that in cases of relatively small mast rake, some of the tops didn't have to be 'dead level' ... and ships do pitch and roll - so the only time a 'level' top would actually BE level would occur when docked or when becalmed.  That is, unless one wants to consider the very instant the surface of a top passes through the theoretical 'level' point as the ship rolls and pitches.

 

  Check out the Vasa on completed builds - its main mast has what I'd call extreme rake, and the main top is built at a deliberate angle to the mast to be level.

[Keith Black]

18 minutes ago, Snug Harbor Johnny said:

Check out the Vasa on completed builds - its main mast has what I'd call extreme rake, and the main top is built at a deliberate angle to the mast to be level.

Johny, the Wasa is a perfect example of the issue I'm having trouble with. It appears the rake on the main and mizzen are set at approximately 15 degrees while the fore is set at zero or close to. For the main and mizzen tops and caps to be parallel with the waterline the bow needs to pitch down 15 degrees and that puts the foremast top and cap 15 degrees out from being parallel with the waterline. 

 

 i can't imagine that sailors aloft would have found or been exposed to any more danger working on a top x number of degrees from being parallel with the waterline any more so than working on a pitching top in heavy weather in daylight let alone at night. The guts those men had is beyond my comprehension. I say men, the apprentices were mere lads of 13 to 15 years old. 

[Snug Harbor Johnny]

  Sailors before the introduction of foot ropes (as Louie da Fly has illustrated elsewhere) had to set/furl sails astraddle the yard ... or else as pictures in contemporary art - they walked the yard.  This is something like 'high steel' workers have done since the invention of skyscrapers built of girders.  Design, materials and safety rules/devices have changed in recent decades - but there are b&w movies of ironworkers walking (or sitting having lunch) on steel beams dozens of floors above ground level ... with no net or safety harness.  Talk about 'guts' - or nerves of steel.

 

  'Guess its all about what one is used to and has grown up with.  Oh yeah, how about the old custom of a 19th c. warship coming into harbor with a good part of the crew all standing on the yards to make a good show !

[Roger Pellett]

There is a classic movie taken by Irving Johnson rounding Cape Horn aboard one of the large four masted steel barques.  The movie starts out with him practicing for the voyage by standing and balancing on top of a telephone pole.

 

Roger

[BANYAN]

Thanks all for the valued comments.

 

Keith B.  WRT to fitting/making caps that are parallel to the waterline, checkout the pdf drawing at post 3.  These were cast iron so creating something with the correct internal angles (for rake - see dashed lines in the drawing) is not difficult at that time, and such a fitting will have held the masts snuggly and without offering injury to them.  I agree, sailors will not have had any real issue working tops at any angle, but in earlier days the angle may have been a consideration for the marine sharpshooters posted in the tops?

 

Rob, thanks, I did not post a full picture showing the waterline as that only leads to more confusion based on the angle/aspect the artist/photographer used.  Generally, with one exception the angles are close enough (allowing for some distortions) to suggest that the caps were set parallel to the waterline.  I agree, aesthetics was also important, and I think, based on the correspondence I have from the designer to the build superintendent, that aesthetics was a design consideration.   

 

Roger, that indeed was an eye-opening movie; he must have had an extraordinary sense of balance akin to trapeze/high wire artists.

 

Overall, the weight of evidence I have found, or been pointed to, indicates that prior to the mid-19th century, there is a mix of perpendicular to the mast and parallel to the waterline for the caps, but it appears that generally the tops were parallel to the waterline.  After the mid-19th century though, it appears that generally the caps and tops were both parallel to the waterline - BUT, as with all of these 'rules' some exceptions to the rule must be entertained.  Therefore, perhaps the best guidance I can follow is that offered by the imagery of Victoria, and while there is some contradiction between the lithograph and the photograph, the best interpretation I can make is that they were all parallel to the waterline.

 

I remain open to further comment and suggestion and would dearly like to find some irrefutable primary evidence to confirm either way.

 

cheers, and thanks all.

 

Pat

 

[Keith Black]

Pat, I keep coming back to this point and no one is providing me a satisfactory answer. I asked the following question in post #15....."Johny, the Wasa is a perfect example of the issue I'm having trouble with. It appears the rake on the main and mizzen are set at approximately 15 degrees while the fore is set at zero or close to. For the main and mizzen tops and caps to be parallel with the waterline the bow needs to pitch down 15 degrees and that puts the foremast top and cap 15 degrees out from being parallel with the waterline." Plus the rake for each mast could be changed at any time at the captain's discretion regardless of the time period. How were mast constructed so they'd be parallel with the waterline when the set of the rake would possible change at any given time.

 

 The photos I have of the Tennessee seem to indicate the mast were raked and the tops are not parallel to the waterline indicating the tops and caps were constructed parallel to one another and 90 degrees to the mast. I'm sorry if this is a case of me being a thick goober. 

 

 

 

[rwiederrich]

OK *Goober*.....😜 Let me take a poke at it.

 

For general peir side symmetry, the tops were typically set parallel to the waterline.  At the time period Vasa was constructed the tops(Or Nest) was perpendicular to the mast axis and they did indeed lay at the rake of the mast.  Mast inclination of this time period varied remarkably between fore and main/mizzen/lanteen.  In many cases the foremast leaned forward 5~10 deg.  Ship designers experimented with all kinds of arrangements to gain better control and advantage of the wind.  Vasa's main engineering error lied in her top heaviness.

 

Typically the rake of each mast is set , do, to the location of each masts foot in the keel bed....so arbitrarily  changing the rake was not a real option. Not even for the Captain.  A *sprung* mast is an entirely different subject.

 

Again, the top platform was typically set parallel to the waterline....establishing a clean balanced and symmetrical view.  The pitching and rolling of the hull in the ocean paid no respect to the design of the top or the cap, nor their relationship to each other.

 

I can't speak for your observations of the Tennessee, but she is a more modern design and would generally have her tops parallel to the waterline....not necessarily her caps.

 

Perspective of any image can throw off the actual top inclination, due to the roundness shape of the top.....hence, the general practice rule has to be your guide.

 

Rob

[rwiederrich]

On 1/6/2023 at 3:54 PM, BANYAN said:

My real issue with the left (drawing version) is how they will have press-fitted the iron cap on at such an angle - which sort of drives me to the perpendicular anyway.

Pat...the cap was not press fitted to the mast as would be the practice for mast banding. (The cap was only pressed and pinned to the mast it was the cap for)  The topmast and subsequent upper masts easily slid through their caps for removal and replacement.  The caps only held the mast in relative proximity to its mating mast at the doubling.  If one removed the topmast cross trees and rigging....you could remove the topmast easily by way of removal of its fid and down through the cap and top goes the defective topmast to the deck below.

 

Mast components were fluid and had to be easily removable to repair them when at see.  It WAS the standing rigging that gave rigidity to the masts.  Main Masts could get *sprung* (losing or extreme shifting of its wedges that are covered up by the mast coat.  However, a sprung mast could still be made rigid enough by way of the shroud and backstay lanyards.

 

Rob

[wefalck]

A general problem is that a lot of the mid-19th century books are re-editions of older issues and typally re-use the same plates for decades, that have been drawn based on earlier 19th century practices. There is a conspicuos absence of books that show iron fittings as became more common from the middle of the century on.

 

I looked through some French and German sources, but when there are plates, they show the old-style wooden caps and upright masts, where the question does not arise (see comment above). I still have a Dutch, an Austrian and a German source to consult, when I have access to them again next week. The latter may not be so helpful, as it mainly deals with iron masts.

 

Overall it seems that caps were perpendicular to their masts, while tops are +/- parallel to the sheer or the waterline.

 

Pat, are you sure the caps were cast and not forged? I would have thought that wrought iron at that time would have been stronger than cast iron.

 

As to the design, I would have thought that the outside walls, also for cast-iron pieces, would be parallel to the inside walls, i.e. of equal thickness. Mechanically it does not make sense to have a prismatic cap and put oblique holes through them, though it would be technically not a problem to cast such pieces. The extra material does not add strength, only weight a-top.

 

A similar discussion arose a few days ago in a German, whether ratlines would be 'horizontal', i.e. parallel to the waterline, or parallel to e.g. the sheer. My response was also that 'horizontal' is relative and irrelevant, once the ship is at sea ...

 

[BANYAN]

Hi all, and again thanks for the feedback and comments.

 

Keith, as Rob has said, from the mid-19th century on, most sources/evidence seems to suggests the caps were parallel to the waterline with perhaps some exceptions.  The side view drawing provided shows how the cap will have been fitted to achieve a parallel fit.  This arrangement would have allowed the cap to be first fitted to the lower mast head squared tenon, in the same way as wooden caps were fitted (which used an angled tenon to prevent the cap drooping forward).   As the square hole in the cap was the same shape but, set on an angle, it will easily have accepted the tenon - the base of the tenon (stop cut) will have been angled to match/offset the rake and let the cap sit square.  Essentially, we are just putting the angle on the mortice rather than the tenon.   If you project a triangular piece of the tenon protruding on the forward upper end of the squared hole in my first post left hand image, it might help with this description? Once snugged down, the cap will have sat parallel to the waterline, then the topmast raised through the round hole to the front which was angled to the rake of the mast so that it would have gone through quite easily and remained parallel to the rake for that mast.

 

Rob, agree, not sure if I said press fit though?  As far as I know they were iron and had sufficient clearance in the holes to allow for leathering and the mast to fit with a little play for the topmast - as you say, the rigging kept the masts rigid.  However, I think the squared after hole to fit on the lower masthead tenon, will have been a snug fit to keep the cap in alignment fore-and-aft.  One of the authors (I think Lees) points out that the cap hole was squared to keep the cap squared to the masthead.  

 

Eberhard, as to cast or forged iron, not sure which; the contract simply called for iron.  Agree on the equal and parallel wall thickness (where possible) - I have allowed 1.5" iron all round, and room for leathering and .25" play for the topmast as suggested by the authors (Fincham in particular).  I should have provided the top view of the cap which shows that.  I am basing the shape of the top on that depicted in the lithograph which shows a rectangular shape (side on) rather than a parallelogram, which means there will have been more 'meat' in the fore and aft ends to accommodate the slope (=weight as you suggest).  A sloped ends cap would/should have been depicted otherwise?  An alternate is that the cap, as built, was wooden, and changed to iron during the mast/top replacement in 1860/61.  I am very open to alternate designs in iron.  The model I depict is right on the cusp, but probably with the older masts when deployed to the Wars in NZ (1860).

 

I think am going to have to ponder on this a little more.  Much too much guesswork here without some clear primary evidence or guidelines from the time.  One thing I will redo is look at the embedded images as underlays in my CAD drawing and see what angles are actually depicted rather than what they seem to be doing.   I am still not convinced either way.  If I go by 'as built' they will have been squared and (based on the lithograph) possibly set perpendicular - but the imagery is confusing.  If I go by the photograph, the cap is more likely to be parallel to the waterline and be an iron cap with equal thickness iron walls all round.

 

cheers

 

Pat

Edited January 14, 2023 by BANYAN

[mtaylor]

Just a curiosity if I may.  The masts were set at the shipyard initially as I understand it but once the captain was in charge he could change it.  So what angle was the mast set to initially?  And if subsequent captains took over and changed the angle changed with reference to the deck or water line, were they changed out?  Modified using small wedges?  

[druxey]

Yes, the trim of masts could be altered. One method was by adjusting the wedges at the partners. Another method (in use in the 18th century, at least) was a moveable mast step that could slide a few inches fore and aft along the keelson. it was secured by pairs of wedges fore and aft of the step. The wedges rested between the step and bolts driven into the keelson..

[Roger Pellett]

Wefalck’s post above suggested another train of thought.  How were these caps made and how did it affect their design?  As there does not appear to be any functional or structural reason for parallel vs perpendicular caps manufacturing processes must have played a role.

 

Casting-  By casting, a part of virtually any shape could be formed.  The process requires, however, a skilled pattern maker, a skilled foundry man, and an iron foundry.  If the part were cast then the term “iron” refers to cast iron which is an alloy of iron and carbon; very high carbon.  Cast iron has poor ductility.  It fractures suddenly  rather then deforms.  Cast parts often have interior voids that further weaken them.  In the Nineteenth Century, inspection techniques capable of finding these voids did not exist.

 

Castings would have been expensive, perhaps needing to be imported, and structurally less than ideal.

 

Forging (blacksmithing) -  If the mast cap were perpendicular to the lower and top masts, the cap could be easily hammered up from wrought iron strip by a blacksmith working in the shipyard.  A forged cap intended to be parallel to the waterline with the angled holes  would be difficult if not impossible to make  in a simple shipyard blacksmith shop from wrought iron strip.  Keep in mind that the only welding process available was “forge welding”; heating the two pieces to a high temperature and hammering them together.  Depending on geometry welds could be subjected to a load (proof) test, but like castings, other inspection and testing methods were not available.  Some joints could be secured instead by riveting.  Wrought iron would have been an excellent material for this application it’s stringy microstructure makes it tough.  Ship structures made from wrought iron (SS Great Britain) have stood up remarkably well in the maritime environment.

 

Forged wrought iron caps would have been inexpensive, and within the capability of the local shipyard.   While welds could have been a problem these caps would have been structurally sound.  Welding could be avoided by riveting.  Fabrication techniques would have limited geometry.

 

This analysis favors caps perpendicular to the masts.

 

Roger 

[Jim Lad]

Hope this might be of some use.  I finally managed to dig out my old copy of H. Paasch's "Illustrated Marine Dictionary" of 1890.

 

These two plates are of an iron ship's iron lower mast and wooden topmast and topgallant mast.

 

John

 

[rwiederrich]

2 hours ago, Roger Pellett said:

Forging (blacksmithing) -  If the mast cap were perpendicular to the lower and top masts, the cap could be easily hammered up from wrought iron strip by a blacksmith working in the shipyard.  A

I propose, that even caps and other fixtures where easily made from wrought iron straps that required to be parallel to the sheer or waterline that were intended for raked masts.  This image of Glory of the Seas bowsprit cap is evidence that off perpendicular forging of bands was possible to achieve in house.
Rivets included to affix the fixture to the Timbers. 
 

Rob

Edited January 14, 2023 by rwiederrich

[BANYAN]

Thanks again for the additional contributions; this will be a valuable resource for others also, I hope.

 

Mark; the rigging of the ship in this instance was set-up in accordance with the new Captain's wishes.  Initially, the masting and rigging was to be to RN standard, as the build superintendent was an RN Commander.  However, when he decided not to return to Australia, he passed the masting and rigging supervision to Commander Norman (ex-merchant captain) who brought her out and commanded until 1867.  I have found a bit of correspondence on this matter which helps a bit, but apart from mentioning some sails does not go into detail other than to state the rigging was altered in parts (mainly the yards) to 'merchant ship standards'.

 

The ship sailed with, and going by the imagery retained, the rakes of the mast as 5 degrees (foremast), 10 degrees (main) and 15 degrees (mizen).  

 

John, thanks for the images which appear to support parallel to waterline.

 

The following illustration (Main Mast-Head of a Steam Vessel) is from Kipping, Rudimentary Treatise on Masting and, Mast-making and Rigging', 1854, p15.  This shows the masthead was indeed squared for a cap.

 

 

The following is a quick alignment exercise I did to try to determine the alignments of the caps and tops using the lithograph (as built) and a photograph (1865).  I don't think anything concrete can be determined as the distortions introduced accounting for the aspect (point of view) used by the artist/photographer shows the lines all over the place.  perhaps, if a little allowance is made for this, the best interpretation is that they were paralleling the waterline (well the tops at least).  Ignore the hounds I have drawn, as they were done before this exercise.   Essentially, I embedded the images, scaled them to the correct waterline to match the profile (taken from the sheer drawing) and put on lines aligning with each mast fitting.

 

Again, many thanks for all the feedback and suggestions; much appreciated.

 

Pat

Edited January 16, 2023 by BANYAN

[Keith Black]

 Pat, Goober gets it. Victoria's sailing characteristics were set at the dockyard when she was built. The bottle screws were intended to keep the wire rope taunt only but never for rake adjustment.  Ships with deadeyes could change mast rake if a captain felt the sailing characteristics of his vessel needed adjustment. Your post #612 in Victoria's build log adds enlightenment to the discussion here.