Molded size of frames/futtocks?

[Gerarddm]

In all the books I have been reading ( feverishly, trying to get up to speed ) about plank-on-frame construction, nowhere do I see any mention of how to dimension the molded size ( i.e. the fore/aft faces ) of frames. Even Underhill, in Volume 1 of Plank-On-Frame Models, page 8, doesn't mention or show this.

 

Clearly one has the shape of the frames; in my plans for Davis' Lexington he shows the sided size ( i.e. thickness ) of the frames; but no mention at all of how wide the face of the frames would be at the keel, nor how they would gradually become less wide as one went up to the sheer. 

 

Obviously the frames of something like Victory or Constitution would be beefier than a 16-gun armed brig like Lexington. How does one go about correctly sizing frames/futtocks?

[mtaylor]

On commercially available plans/monographs such as those by ANCRE, Seawatch Books, and others, they're all ready drawn.   Otherwise if you're drawing your own build plans from the lines drawings, you'll have to locate the scantlings.   If English, the NMM probably has them.

[Mark P]

Good Morning Gerard;

 

As Mark says above, commercial plans may give you the answers you want. If this does not work for Lexington, then you will have to calculate or locate the dimensions. There is some confusion in your post, in that you mention you are looking for moulded dimensions, but then state that this is between the fore and aft faces. Then you seem to correctly describe the sided dimension. So it appears that you are correct in knowing that you are looking for the moulded dimension, but this is the distance between the inboard and outboard faces of the futtocks etc. 

 

In the Royal Navy, where the most plentiful records survive, everything was proportional to one of the principal dimensions of the ship. Originally this used the length of the keel, but by the 18th century, the length of the gun-deck, ie the length between perpendiculars, was used. Every dimension in the ship was then calculated as a proportion of this. 

 

As gun-deck length was fairly standard within each class, both these systems led to a high degree of standardisation. As large numbers of the shipwrights working in the original colonies or other parts of the Americas would have been trained in England, it would seem a reasonable assumption that the early American vessels were built using the same or a similar system. If there is no known record of the moulded dimensions used for Lexington, or similar ships at the time, then to use the RN's system will certainly give a viable method, even if Lexington was originally built as a privateer, which I think is the case here. 

 

If you can locate a copy of a builder's contract for a Royal Navy brig of similar size, this would be a good source for moulded dimensions. Alternatively, Allan Yedlinsky has compiled a book of scantlings used in the Royal Navy, available from Seawatch. I am not sure if this covers ships with two masts, but Allan is a member of this website, and he will be able to confirm this for you. I would suggest sending him a personal message (he is here under his own name) as he may not see this post otherwise.

 

Note that moulded dimensions normally reduced at several points going forward and aft, so they were not constant.

 

All the best,

 

Mark P

[vaddoc]

I think such info can be found in "The construction and fitting of the English man of war.1650-1850" by Peter Goodwin. He seems to have studied all the dimensions and the rules they used back then. The book is full of numbers and calculations! 

[trippwj]

In the case of the Lexington (originally a merchant brig), it would an error to try to apply the scantlings from the Establishment (see book by Yedlinsky and some extracts in the Humphrey's Papers).  These scantlings were for a custom built war ship - a merchant vessel would likely have more space and perhaps less robust scantlings for the frames.  You may have some luck by contacting the Mystic Seaport Museum as they have most of Davis's files in their archive.

 

https://research.mysticseaport.org/coll/coll253/#head58871776

[Gerarddm]

In fact I contacted Mystic Seaport a couple of weeks ago about any information they may have on Davis' Lexington since they have his model. I got back a quick reply saying it would take them a few weeks to cogently respond, so we shall see. 

[Jaager]

I have been collecting data for a while.  My attitude towards this is - close enough is good enough -  I will take a sword to this Gordian Knot rather than let usually insignificant detail deter me from undertaking a project.  The material in question is wood.  There are limitations on strength vs load and the dimensions needed to obtain that strength that have not changed.  Unless you are building a cross section model,  it is very difficult to see minor differences in moulded dimensions.

Sided dimensions - in the usual situation where the numbers are not available,  I use tables of scantlings that as close in time as I can get.  

If you have room and space (R&S) - those are the outside limits.  This usually a bend (two frames) and the open area to the next bend.  The scantlings usually give you the sided dimension for a frame. R&S minus 2xframe = space.  Worst comes to worst and you do not have R&S,  the distance between stations is an integral of R&S.  That integral varies with the style of the designer of the vessel.  I have seen that integral go from R&S x 2 to R&S x 8.   (HIC copied what the original draftsman provided and I feel that the original draftsman for USS Falmouth was lazy.  For the plans for that ship, the stations are too widely spaced.)

 

1670  - DEANE'S DOCTRINE OF NAVAL ARCHITECTURE

18th C.  Yedlinsky's collection   -  Mungo Murray

19th  C.  Richard Meade's Treatise

              American Bureau of Shipping Rules  I have 1870, 1885, 1903

              John Griffiths   Ship-Builder's Manual

Edited January 9, 2020 by Jaager

[Mark P]

To clarify Jaager's post above, see below a sketch I made to illustrate room and space. This is based on a distance of 2'8 3/8", the room & space for a 74 gun ship, Ganges, and shows the station lines at 10, 8 & 6, at each of which there would be a double frame, or 'bend' located. Between these station lines lie 2 filling frames, which, being single, are not bends. The exact spacing of the filling frames could vary relative to each other. Note that other patterns of framing were used, but this will help to understand how it works. 

 

All the best,

 

Mark P

 

 

 

Edited January 9, 2020 by Mark P

[Roger Pellett]

There is information that is becoming available from the Nautical Archeology people.  Several Revolutionary era vessels have been excavated in Penobscot, Maine.  I believe that the most complete is the brig Defense (or maybe Defiance?)

 

The regularly spaced doubled framing shown by Davis is much later American practice.  There is some archeological evidence that for small vessels in merchant serrvice, floors and futtocks were not necessarily connected to each other.

 

Roger

[trippwj]

How would these various methods relate to a Bermuda built merchant brigantine like the Lexington?

[Mark P]

Good Evening Wayne;

 

Your questions raise a good point. But if there are no records of how merchant vessels were built in this period and location, who can say what methods and sizes of timber were used. Archaeology may have some good indications, certainly, as Roger mentions. Where the local shipwrights were likely to have been trained would give some indication also. On Bermuda? If most were immigrants, they would bring their own traditions. 

 

I was looking at an original copy of the 'Shipbuilder's Repository' only a few days ago, and the unknown (but very knowledgeable) author included a section on the scantlings of merchant vessels. Unfortunately I did not photograph this part, as I concentrate on warships, but the author's opening remarks to this section indicated that merchant scantlings could be heavier than those of Navy vessels. This seems counter-intuitive, and as I only skimmed it briefly I may have not really taken it all in, but I am sure that this was the import of his remarks. 

 

If anyone reading this has a copy of the Repository (which is a very informative and information-packed volume) maybe they could check the beginning of the merchant vessel section and confirm/correct my impression, and expand on what is said there. The book was published in 1788, so will relate to ships somewhat earlier  than this date. 

 

Yet whatever is said there is still not provably relevant to Bermuda, as you say. In the absence of any firm evidence, all that can be done is to choose one of a variety of options, and stick to it. In which case, it is probably best to choose one which is not only a possible method, but one which is fairly-well documented to avoid too much guesswork being needed. 

 

All the best,

 

Mark P

[Roger Pellett]

A number of years ago there was an article in the Nautical Research Journal by a highly regarded British ship modeler (sorry, I don’t remember who) about modeling beyond the limits of available research.  The point of his article was that the extent of and level of detail should be limited to known information.  The example that he gave was that a model of the Mary Rose should be limited to a pair of mastheads and tops sticking out of the water.  This was before the vessel’s remains had been extensively studied.

 

His point was well taken.  Why build a plank on frame model with exposed framing if you know nothing about the original vessels construction details?  Instead of building a wholly fictional model of the Lexington build a model of another Bermuda built vessel of the same era- Chapman’s Bermuda built sloop.  But don’t show exposed framing based on dubious information.  Exhibit your craftsmanship by fully planking it.

 

Roger

[Jaager]

Ummm.....  did not the guys who essentially started all this in the 17th C.  often build models with exposed frames,  with framing that was highly stylized ? 

It all comes down to what is your purpose for a particular build.  It may be satisfying to produce an academic model,  but the museums that would appreciate the effort do not seem to be very interested in models.

A fictional Lexington would be a poor choice in any instance.  An obviously stylized POF effort using a plans documented subject, should not confuse a distant future historian.  I see no problem with duplicating what is known and filling in the blanks with what is probable based on available evidence and adding a bit of art as regards the framing.  The open framing of an actual ship was likely very ugly and irregular.

 

About Davis,  to repeat myself,  I think he represented a building method that was heavily influenced by the methods needed for iron and steel hulls.  The chain of knowledge for all wood construction of master to apprentice was broken about 1860.  The old methods were lost.

[Roger Pellett]

Large wooden vessels, especially large Schooners continued to be built in American and Canadian shipyards into the 20th Century.  Many large wooden Schooners and steamships were built in American yards during the World War 1 shipping crisis although most were completed too late to be of use.  The technology used to build them is discussed in Charles Desmond’s Wooden Ship-Building, first published in 1919.

 

It is my understanding that Charles Davis worked in yards building these wooden ships and this experience influenced his understanding of much earlier wooden ship construction.

 

Roger

 

 

[Mark P]

Good Morning Gentlemen;

 

A model with stylised frames would indeed be a good way of building a framed model in an instance where the true framing pattern is unknown, and would follow on from a long tradition.

 

I would like to make one comment on the Navy Board pattern of framing models, though. Which is that the most common method of construction depicted in such models does actually represent a technique used in full-size practice in the early 1600s, and perhaps earlier, and was not as stylised as many authors have stated. Construction using interlocking timbers is documented archaeologically, and is specifically demanded in some early ship-building contracts. Interlocking floors and first futtocks continued into the early 1700s in some instances. 

 

A frame produced using interlocking timbers is actually very strong structurally, but was discontinued, I believe, for three reasons: firstly, the need to use relatively thick futtocks to maintain contact between adjacent timbers, which became harder to satisfy as timber shortages began to bite (this is already being complained of in the mid 1600s) Secondly, the fact that the relatively large spaces between the timbers (outside the areas of interlocking, which were obviously very strong) provided no protection against cannon-shot penetrating the ships' hulls. Lastly, the close contact between timbers encouraged dampness, which led to the onset of rot.

 

All the best,

 

Mark P

[Jaager]

Mark,

I completely agree.  Following the Dutch methods as they evolved shell first to frame first construction shows how the framing style evolved.  The timber ventilation problem could have been somewhat abated by using 1"-2" chocks to produce a space.  I have seen RN plans where the bends had a gap.  But it is not something I would care to replicate in a model.  There is another possible reason that the overlapping floor and first futtock style was abandoned.  In investigating  framing Le Saint Philippe using the Navy Board pattern,  I found that both the floor timbers and the first futtocks would have been impossibly long.  The arc that each described would require that the stock be unrealistically wide.  Oaks do not generally have 15-20 foot diameter trunks.  (The monograph shows a modern framing style using bends.  I suspect she was an experiment.  But, in an attempt to solve a strength problem that did not require a solution, the designer doomed the ship to accelerated fungal rot. The timbers did not just meet at the mid line, there is an alternating table joint.)

[mtaylor]

I thought the space was a requirement.  True, it might have been very small at some point but it was there for ventilation to let moisture out and prevent rot.   

[noel_colledge]

There may be one relevant information on Vanhorn's document Eighteenth Century Colonian American Merchant Ship Construction on the following site

 

https://nautarch.tamu.edu/academic/alum.htm

 

My apologies if if is the wrong era for you.

 

Regards

 

Noel