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HBMS Amphion 1798 by Matrim - 32 Gun 18pdr Frigate

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Hi Joss,


You're doing some excellent drafting on your Amphion, she's coming along beautifully, and I'm learning a lot from your splendid work :)


Just a small question if I may: could it be possible that the original NMM draught may have had some minor horizontal/vertical distortion thereby leading to the slight difference in it's gunport dimensions from the scantlings provided by Steel?

Edited by rdsaplala
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I would even say probable as far as distortion is occurred. The thing is the difference in dimensions is not slight. The Height is arguable at 1 inch but 4 inches for the width is not. Admittedly that is only 2.12mm but with these final measurements I was using the inward lines of both measurement points so the far right edge of the left side of the port and the far left edge of the right side of the port. Any other measurement point could add another mm and hence another couple of inches (coming close to the 38 gun ship port sizes) .


The other thing is that all three plans with gunports agree with the width. If it was one then you could say problems with distortion. 





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Thanks for any comments all. 


Time to move on with more general warblings. I re-arranged my methodology slightly as I rapidly realised my frames would need more work than I previously expected. Basically

you have the choice of three options here (for the square frames)


A - Keep the frames a fixed siding and completely vertical - gun ports would have to move to match the new frame locations. This is the simplest build option but is also the least historical (though I do

ask myself who would even notice)


B - Keep the frames a fixed siding and completely vertical but introduce some declining frame sidings where necessary to match the gun port locations as recorded from the plans


C - Follow the historical framing plan



Now I intended to utilise 'B' but found I needed so much declining sidings that I might just as well do 'C'. So this is what I switched to.


To make this job easier I removed the square frame layer I had earlier produced and then generated a quick hand drawn picture to remind me of the frame locations (in this area of the ship the left of the

frame would contain the lower or 1st, 3rd and toptimber and the right the floor, 2nd and 4th. 


My contract provided the relevant dimensions as follows for the midships area (9-G)


Floor  13 inches

1st Futtock  13 inches

2nd Futtock  12 inches

3rd Futtock  11 inches

4th Futtock  10.5 inches

Toptimber    9.5 at top of sides except when bordering a port in which case 11


So armed with this I can start


Here is my working area. The frame I will be working on is Frame B




The black square is the sized gun port. The green fixed lines are from the trace of the framing plan with the dashed line representing the framing plan station line.


The purply line is my station line.


So I start at the keel. Here I simply drew parallel constructions 13 inches from my station line as follows




and then drew in the floor




followed by the lower/1st futtock




At this point I needed to return to the gun port which is bordered by the left hand side of this frame and here I drew a construction line




This relates to the toptimber so the width bordering a port is 11 so a parallel soon provided the shape of the top timber






Next up I looked at the 3rd. As always I returned to the framing plan




As you can see (ignore the 'new' purple lower timber) that on the original plan the 3rd matched exactly the left side of the lower. So I placed a construction

there and then paralleled a line at 11 inches - which is the 3rds width






Now to the 2nd. As before I checked how the framing plan coped




Here the left border is again exact. So I placed a vertical construction and then put a parralel out 12 inches




and drew it in.




Finally we have the 4th







So here is the final frame with diminishing sidings. I shall be slowly following this process for the rest of the frames.




Though time consuming (and I am not particularly looking forward to all the different thickness's of wood required when cutting the frames out - no more placing all parts of a frame on one piece of wood) this will have the historical thinning and lightening of the sides on the model and thus more weight in the centre lower section of the ship.






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Roman Pm'd me an interesting question. Plus as I do not know the answer I thought I would stick it out here to see if anyone with more familiarity with British ship building practice could answer..





I am curious about the Sheer plan and disposition of frames . These show gun ports directly above other gun ports aft section. Was this a permitted practice by the British.


My 'guess' back



It is an interesting question. If you look at ships like the victory they did try and alternate the ports between decks (so the lowest gundeck had ports at the same place as the quarterdeck). Other frigate designs also appear to attempt to split the ports - if you look at the Trincomalee only one quarterdeck port matches an equivalent gunport. 

It does seem more deliberate in the Amphion classes case though which might be due to the large number of carronades on the quarterdeck which would reduce both weight and potential damage against the ship frame. Also the larger 36-38 port size combined with the 32 framing mean that they may not have had enough space to do anything different without losing guns and making the ship less effective.


and Romans Response



This practice would have been unthinkable in the French or Spanish navies, due in part to the rising gasses from the gun underneath. It would handicap to crew of the gun above, not to mention the potential for harm should catastrophic failure take place below or above. It is interesting. I guess it is just a different school of thought. We should have posted this on the thread time line. 



So anyone know?  Since I got back from work I have since had a flick through Gardiner and though the practice is not everywhere it certainly can be seen enough to be termed widespread. I.e Hyperion class, Seringpatam and the USS President etc etc. I wonder whether the rigging setup defined the quarterdeck gunport placement and what would have been the British thought with regard to gas (no bean comments please) or exploding guns below...




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Let me first say that I love this frigate and I love your work!


The inboard profile plan of Leander, 50, 1813, shows the spar deck ports mostly above the gun deck ports. Leander was a fir built ship. (Sadly the lines drawings have been lost, but the deck plans and frame plans survive.)  The model of a fir-built (with a square tuck stern) 50-gun frigate, thought to be possibly Leander, but minus the gangway ports, in The Science Museum has the same set up. There is a detailed painting of the USS Constellation, circa 1830, by one of the better Italian marine artists of the day, showing all her spar-deck ports placed exactly above her gun deck ports.


In my long suffering thread on the Essex's stern, (Page 1, Post # 8) I quote a 1807 letter written by American Naval Constructor Josiah Fox on the subject of upper deck port placement that may be of interest here.


Also, I was wondering what you thought of the "Later Amphion" revised sheer draught, dated February 1, 1800, that shows a complete barricading over of the forecastle ports of her sister-ships Aeolus and Medusa. Would they have done the same with the Amphion? (See Robert Gardiner, The Heavy Frigate,  Conway, page 48-9.)  

Edited by uss frolick
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Seems like this practice was quite common at least in terms of being illustrated on British draughts. The Artois class designed by Sir John Henslow 1793, Surprise 38 guns of 1810 and the Bacchante Lively class shows similar staggered  arrangements. On the other hand Hyperion 32 guns  by William Gibson ordered 1805, Granicus 36 guns and a few others show some of their ports directly above. All very interesting, thanks for posting it Joss.

Edited by Roman
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That quote concerning US practice is so useful I will place it here as well (cheers Frolick)




" .... All the Fore Castle and quarterdeck ports in out frigates (the Chesapeak [sic] excepted)  are equally spaced between the ports  on the Gun-deck; This mode (though uniform) is attended with great disadvantage to the direction of those guns,  particularly Carronades,  where the Ports are in the wake of the Channels; It is usual with all Nations to place their Fore Castle and quarterdeck ports in their frigates between the same Shrouds that are spaced for the Main-Deck ports, by which means the shrouds have less spread fore and aft, and being more abreast of the Mast, afford more support to the Masts than they do now; and at the same time enable the Guns to range clear of the Shrouds, and point to more advantage than in the former mode ..."

and a link to Frolicks discussion should anyone like to see the full



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Roman and Joss,


Interesting discussion on the gunport/position placement.  The rule may not have hard and fast for the French as well... On Licorne, quarterdeck guns are placed between the ports on the gun deck.  On the foredeck, however, they are directly over the bridle port. 


I've done a quick search on other sites and it seems the rule was applied but in the case of Licorne, it wasn't.  Interesting to say the least which makes me think the bridle port may have empty.

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Hi Mark, La Licorne 1755 has been compared at times with La Renomee, as I do not have the plans to La Licorne I reffered to  Renomee and there I see the staggered arrangement. From my perspective it is curious, at times I feel that it almost looks like an after thought to have these immediately above the main ports. Much the same way Boeing Aircraft produces an airframe for 300 passengers and the airline adds another 40 seats to pack us all like sardines. (Sorry my feelings for airlines was not meant to be public). I guess that was my initial thought. The period in question however is 1790's and by this time the science was well established but obviously not standardised. Interesting indeed Mark I will have to seek out your build of La Licorne.



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Its been a while since I have read it though it is on my shelf. If you are looking for a copy they are some still floating around though your best bet is an e-book at around £2.


The book is okay for self-published. The author has looked at the various easily accessible sources (progress book) and picked all the relevant low hanging fruit on the ship. So he covers Hoste (in some detail) as there exists a biography, O'Brien's rejoining the ship in the adriatic as again there is a biography and interspersed the rest with details gleaned probably from the Navy Chronicle.I do not doubt he has looked at the musters but only a brief scan except perhaps the initial muster. There is some evidence he has picked and chosen from the captains logs as well.


I am going into a lot more detail myself but once you avoid the 'low hanging fruit' you have to join the dots far more and investigate everything you can. As an example Bennett (the first Captain) has several reports in existing books (though not many) but looking through the NMM I picked up his court martial (which linked the 2nd captain Alexander Fraser to him as he sat on the court martial) and in his service history noted he served with Collingwood in the Americas. Now at the time he was serving with Collingwood, another Mid on the same ship also wrote a biography. Now he is not mentioned directly but that biography does give an impression of serving on that ship and what the other mids were like which covers Bennett and also provides potential explanations for Bennetts possible unwillingness to serve under Nelson.


Now admittedly none of that is relevant directly to the ship but if more useful than a compilation of information gleaned from other sources and the amount of information you can grab by getting all the officer service histories or letters from.to the captains or even number crunching the musters to find desertion rates/where the crew came from are all things which are fascinating (to me) and not done here.



For me (and this is just my opinion) he does not dig deep enough to make the book truly detailed and for a book covering such a large period it is very short. On the other hand he does bring into one location a lot of this surface information and if you are not able/willing to hunt for that then it would prove useful. I found 'Remember Nelso' a better read a book which covered a big section of the Amphions history, Gardiner covers more of the design details and why/where built arguments (not that Feather covers this). There are plenty of general history books which cover the Spanish treasure fleet action in some detail along most fictional books as Hornblower and O'Brian both have Sutton involved in their relevant re-writes of the action.




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  • 3 weeks later...

lol, thanks for that though that would require years more work and I have enough on my hands drawing up the ship...


Anyway a brief update I have finished the outline of the square frames and drawn the cant frames in on the half breadth. I had to think about this. There are several methods for getting these drawn in and most seem to take one of two approaches.


The first is that if you have the framing plan just take the lines from the relevant cant frames down to the half breadth at the keel and the cap rail and just draw them in. I tried this first but was not confident about all the copies of the framing plan (apart from the standard deviation of a CAD line of no width with a line that has width - you also have lines finishing in the air at gunports and unusual 'squiggles' at the top. The decider though was that I had drawn my own frames in and these did not match exactly the originals so it would seem unsafe to suddenly switch approaches at this point.


One thing I had noticed was that the intervening lines of the traced half breadth (all the traces were on layers that I could show to 'validate' my own lines against the originals) followed the center lines of the double cant frames very closely. This then decided me on approach two.




I used these centre lines and measured the width of the cant frames on the framing plan (all around 10.5 give or take a tenth of an inch) so the double frames were simple enough.


Once the doubles were in I measured the gap between them at the keel, removed 21 and then divided by 3 to place the filler frames. This naturally was repeated at the cap rail position. Once in I threw some vertical constructors from the last of my square frames at either end to check there was no unexpected 'gap'. 


This shot shows the 'original' traced frames (in light green), The newly drawn square frames in purple and the cant frames in orange on the half breadth.




The next job is to project my cant frame straight lines onto the main framing plan then I will do a stand alone frame plan..



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  • 1 month later...

Just a little progress report. I had to chuck away all my previous square frames work and start those again. In the process learnt some more turbo  cad lessons. Rather than carry straight on to the quaterdeck barricades, preparing a 'filled' framing plan and starting the hawse pieces I thought it would be better to run back over those lessons before i forgot them.


First up progress (which looks remarkably like some of the previous shots)




In order of importance the lessons learnt were


A) Use the turbocad ;lock ability. At a guess at some point I had accidentally selected all of a layer/group of layers and then hit a key to move it slightly or adjust its stretch/shrink. When reviewing work done against the plans I had noticed the gunports seemed to be in the wrong location. When I looked further I found many other layers were slightly out if sync as well. In the end I gave up trying and found one of my previous saves that was correct (prior to all the frames going on) and utilised that. The little padlock in turbo cad prevents adjustments, whether deliberate or accidental, of the layer in question so it makes sense to have 90% of your layers locked and work to occur just on editing ones.


B) I had been unhappy with the start point of my lines for the cant frames. I had originally started them at their start point but due to the nature of some of the turbo cad curves this meant a more pronounced curve often occurred at the start than I liked. So for the redraw I started the curve at the keel and then cut the 'excess' once the curve was in place.


Now the difference is miniscule but I wanted something I was happier with so










There was also so funky work with what appeared to be a vertical frame extended from one of the cants






Anyway I will probably complete the remaining frame sections at bow and stern then the barricade type thingys before updating again.




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  • 2 weeks later...

The framing plan is now almost done (bar some of the cants at the rudder end by the keel..




So basically I have got back to the stage I had reached when the site crashed... One difference you will note is that I have utilised the Foredeck bulwarks (allowing I have the terminology correct). Most of the paintings (definitely from the Lissa period at least) show her with these and my framing plan did include them though the sheer did not.


Next up is the fish plan (as I like to call it)



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Since I just got the cathead sorted in another post I thought I would bring the log up to date. On on of the plans there is so 'extreme' cathead detail.




The full cathead joins at the center line of the ship with some overflow on the beam




I will scan, size and then just transplant the plan cathead across. Since that beam is practically on the station line and the deck plan does not necessarily relate to the cap rail I shall use that location for placement.



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I think you are on track with your keel/false keel joints, except you might wish to shift the joints of the false keel aft. The first section likely to touch would be aft, so that might be shorter. As the false keel joints do not contribute to the structural integrity of the ship, it's not critical to stagger them exactly half-way between the keel joints. I'd keep any keel taper to the cant frame areas as well. Good stuff, Joss


P.S. Some of us like history: those that don't will skip it anyway!

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Thanks for the comments I should do some more history stuff but I am still number crunching the earlier musters/captains logs for data but usually have to fit that around the other stuff.

My weakness is I do something and then see how to do it better. I have already re-drawn two of the stern cants and shifted their lines on the half-breadth after checking the original against mine and am now looking suspiciously at the forward hawse pieces as I do not like the line shape which moves in an unusually aggressive fashion midships so am suspicious something is wrong. At a guess it is the waterlines as when turbo cad brings its curves sharply round to contact the keel it can 'bulge' as it tries to rapidly bring the line round and in a more aggressive curve. In future an extra midpoint station line at the bow would help mitigate this perhaps. So I may re-address these lines when the fish plan is done.



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So finally placed the cathead. Initially I thought it looked too far back and when I re-checked with the inner works plan I noticed that it was actually attached to the beam in front of the gunport one I was using. When I shifted it forward using the 110 degree angles the plans required it all fit a lot better. The construction line in the following picture has been dropped down from the cathead on the sheer where it contacts the cap rail and as a good confirmation it matches almost exactly the same point down below.


Also matching were Steels inboard measurements. 




What did not match was the outboard. If I threw a line down from  the end of the cathead on the sheer then it was about two foot further forward from where it was marked here. This end point used Steels distance outboard and looks more reasonable though I am open to suggestion about lengths that may not use Steel..



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