Top of Frame Thickness

[Richard Feliciano]

Having an issue with the top of frame thickness for the ship frames.  After cutting the frames down to proper height, the frames need to be reduced to the thickness indicated on the NMM Upper Deck Plan. This seems to be abnormally thin. After conferring with Greg Herbert, he suggested the frames may be only 6" thick at deck level. This will require a lot of sanding to achieve this thickness.

 

 

 

 

[garyshipwright]

Hi Richard. I would go with Greg's 6 inches, and on Montague a 74 gun ship she has 6 1/2 inches thick at the top.  On another note your build looks very good  and will be watching you bring her to life.  Just a ideal but you could scrap the insides which would keep down the dust. Gary

[Jaager]

The RN was kind of unique and particular as well as as being more difficult to replicate. 

The frames were sided in the lower hull (floors and futtock 1/crosspiece/half floor) being almost all wood.  The sided dimensions of fut2 / fut 3/ etc. were diminished.  The higher they were, the less thick their sided dimension was.  It was a step function.  The moulded dimension also decreased, but that was a smooth curve.

 

Modeler's conventions help -  uniform frame sided dimension  until the LWL/main wale.  Plank everything above this and the interior and the frame sides are hidden.  Their actual thickness does not matter.   

 

[Richard Feliciano]

I'll go with the 6". I'm going to fabricate the top timbers separately. I assume they will be 8" thick to be flush with the ship hull. 

[druxey]

Are you talking about the sided (fore and aft) or molded (in and out) measurement? I assume this is for a sixth rate.

[Richard Feliciano]

 I look at this part of the frame above the deck as a cantilevered column loaded on hull exterior by wind, waves, canon balls etc. This part of the frame extension above the deck is in tension on the exterior and the interior portion is in compression. The depth of this beam-column is the distance from the extreme tension fiber to the extreme compression fiber of the frame (i.e.-the beam column thickness).

[Phil Babb]

Hi, 

David Wray ,who I worked with for many years and taught me so much always said eerr on the thinner side, a remark I have always remembered.

[allanyed]

Hi Richard, 

My apologies but I think a few of us (me for sure) have no idea what your post means about extreme tension fiber and extreme compression fiber.  When you say beam column thickness, do me mean the frames,  and regarding thickness is it the sided or moulded dimension?   To make things a little easier, what ship are you building, nationality, name, rate, year, etc?   From the photos and your checking with Greg, it sounds like a Swan class sloop.  If this is not the case,  for British ships,  there are several sources (The Establishments of 1719, 1745 and 1750, Shipbuilder's Repository 1788, and Steel's Elements of naval Architecture (1805) that  give the sided (fore and aft) dimension as well as the moulded (in and out) dimensions of each futtock and  the top timbers at the foot and head of each as well as at the gun ports in the case of Steel.   The moulded dimension also varies  slightly in some cases in the range of the quarter deck and forecastle .

 

Better information is sometimes available from a contemporary contract for the ship you are building or a sister ship in her class.   If this is of interest you can contact the National Archives in Kew and the RMG in Greenwich.

 

Allan

 

 

 

 

 

Edited November 23, 2020 by allanyed

[Richard Feliciano]

I'm building the Swan Class Sloop HMS Fly. Using your description nomenclature, the moulded dimension of the top of frame is what is needed The general consensus is 6" is what is to be used. This checks with my NMM plans. 

6" is thin! A lot of sanding is going to be required. I plan to construct a rigid template based on the NMM  Deck Plans to assure the proper location and orientation of the top of frames.

[druxey]

Actually, for the Swans, the frames at the top of the side are 4½" molded once faired - even thinner!  However, with temporary fillers between the toptimbers the structure should be quite rigid.

Edited November 23, 2020 by druxey

[tlevine]

May I also suggest you take a look at the other Swan class builds.  Putting spacers between the toptimbers made the hull quite solid.  In particular, check out Dan Vada's Fly.