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framing scarph joint bolting pattern


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My build contract states "... are to be framed in bends, 1st, 2nd, 3rd, 4th futtocks and top timbers together, and fastened with three bolts of 1-1/4" diameter in each scarph..."

 

Was there a pattern for laying these groups of three out... possibly diagonally over the length of the scarph (height of the frame)?

 

 

Anything I find shows two laid out diagonally but there is no source to suggest this is correct

 

FYI:

Floor timbers are sided 13-1/2" to 16" 

Top timbers are sided 10-1/2"

Futtocks would be anything from 16" to 10-1/2"

 

Futtock heads and heels are joined with chocks whereas top timbers employ a plain scarph.

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Might this line in the contract alternatively indicate that there were to be 3 fore-and-aft bolts in each scarphing section between the fayed timbers in a bend?  i.e. three bolts to join the top half of the 1st futtock to the bottom half of the adjacent 2nd futtock, etc.  Steel's Naval Architecture has a plate with midship sections showing 3 fore/aft bolts in each of these timber scarphs, and I believe this was a common arrangement.  The scarphs joining the timberheads to the chocks would obviously also need to be bolted, and I'd definitely buy Druxey's illustrated arrangement for them, but I'm not sure that's necessarily the set of bolts being specified in that line of your contract.

Rob

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Steel's Naval Architecture - tables - folio V has a very similar statement under "Frame-Timbers".  The first through fourth futtocks and the toptimbers are to be scarphed or framed together and bolted with either two or three bolts per scarph, depending on rate. The bolt diameter is specified and then it is mentioned that the lower futtocks are to be bolted to the floors in the same manner.  The only way I see the lower futtocks being fixed to the floors is with a fore-and-aft fastener. The remainder of his scantlings for the various timbers typically specifies the scarph length of one timber to the next (i.e. 1st futtock to scarph with the second, second with the third & so on).  I'm pretty sure the three bolts are intended for these fayed scarphs, not the chocked scarphs.

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Thank you all for your help.

 

Here is the exact wording...

 

[Page 4]
FRAME --- It being of the utmoft confequence to the strength of the ship, that all the timbers of the frame should be as much as poffible be preferved from being cut by the ports of each deck, a difpofition for that purpofe is made on the faid draught, and as a further means to obtain it, the faid timbers appointed to make the sides of the ports being continued up to the top of the side, are to be framed in bends, 1st, 2d, 3d and 4th futtocks and top timbers together (as diftinguifhed on the draught) and faftened with three bolts of 1-1/4 inches in each scarph, and that the firft futtocks be bolted to the refpective floors of every bend, with 3 bolts of 1-1/4 inch diameter, that the stations of the faid frames fo diftinguifhed, are to be preferved with great exactnefs, and fo fuch of them as ftands afore and abaft the square frames, and are to be canted, thefe alfo are to keep their stations, at the breadth, and what is required to give the fafhion piece and beakhead timbers a proper flight, or cant,.... (continues)

Edited by AON
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Alan,

My suggestion would be that the 1-1/4" bolts are driven fore and aft, through your filling pieces, with three tying the top half of the floor to the bottom half of the first futtock, three tying the top half of the first futtock to the bottom half of the second, and so on up the frame.  See attached excerpt for a 74 showing these bolts.  In this case, the ones being pointed out are securing the overlap (the term "scarph", in this sense, meaning nothing more than an overlap) between the first and second futtocks.  Steel's tables show, for a 74, that these bolts would typically be 1-1/4". 

 

Steel goes on to mention the joining of the heads or heels of the timbers into the chocks.  For a 74, the excerpts is: "The Heels of the Futtocks to run down to the Deadwood, and to have substance left there" equal to 6 inches (meaning the lower futtocks).  "Not to have less stepping or substance at the Heels of the Double Futtocks, and Half Timbers" than 3-1/2 inches (double futtock meaning a point where a futtock head meets a futtock heel at the chock), "and the Heels bolted with bolts, in diameter" equal to 1-1/8 inches.  All that just to say that, at their thinnest point at the midpoint of the chock, the timbers must maintain a certain minimum thickness, and the bolts that go through should be slightly smaller in diameter than those binding the timbers fore and aft. 

 

Take care to ensure that the bolts fore and aft don't interfere with the bolts through the chocks (they're shown awfully close to one another in the attached pic).

 

Image from Steel, Naval Architecture, Plate 8.  Excerpt from Steel, Naval Architecture, Tables/Folio V.

 

In the interests of full disclosure, I'll confess that late 18th century stuff is not my strongest suit, and it's entirely possible I'm out to lunch on this. If Druxey is not convinced by this, then perhaps more research is needed.  Ultimately, I defer to him on such issues.

post-3634-0-03741100-1457889831_thumb.jpg

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I don't disagree with your posts, Rob. The 3 bolts per that you indicate in Steel are certainly there! However, what bothers me is the wording, "in each scarph". This implies a further three bolts through each scarph rather than between the floors and futtocks of the frame pairs.

 

Now, to confuse you further, I looked things up in Steel's Naval Architecture. The three bolts you indicate (square in section, BTW) are specified as having the same dimensions as the keel bolts. BUT, (page 378) Steel mentions treenails, not bolts, through each part of the chocks!

 

"The frames, when bolted together, have chocks fayed in the seats at the heads and the heels, and fastened with treenails..."

 

I rest the case, m'lud.

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Hi everyone;

 

I can see the thought behind Rob's posts,  and that his posts are correct,  but I agree with Druxey that the crucial part of Alan's initial query is the phrase 'in each scarph'

 

I have read quite a few of these contracts,  and the specification detailing the scarph joints normally lists immediately after it the number and size of bolts to be used to fasten the scarph together.

 

All the best,

 

Mark P

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