Joints

[Don Case]

I think I've noticed that when a timber is scarfed or otherwise joined that the scarfs are rotated 90° at each one. Have I been noticing right? Can this "rule" be broken?

[druxey]

What do you mean by 'rotated'? It would be helpful for you to post a sketch or diagram of what you mean.

[Don Case]

Like this. The scarf by the clamp is 90° to the one by the keel.

[druxey]

Ah! Now I understand the question. Scarphs are generally oriented so that any stress is at right angles to the joint line. The one on the left will resist an up and down stress, whereas the one on the right will resist lateral stress.

[Charles Green]

For naval vessels, I believe it was the country of origin that determined the orientation of keel scarphs.  Blaise Ollivier, on page 45 of his 18th Century Shipbuilding, states that English keels are built with a "side by side" scarph while French scarphs are "one on top of the other."  Page 208 describes the Dutch following the French practice.  As for the German practice, Ollivier's description of the Germans securing keel scarfs with clench-bolts driven up from the bottom suggests that they followed the French practice as well.

 

The Admiral called me away momentarily - to continue:  English stems were scarphed side by side  (p. 84), the Dutch scarphed the stem to the keel side by side then rotated the rest of the stem's scarphs 90 deg. (p. 209).  Ollivier infers French stems are scarphed as are their keels (p. 209), one atop the other.  

 

Ollivier mentions "storeships from the Northern lands", (p. 367)  with stems scarphed directly to the end of the keel and "in former times some Builders used to follow the same practice in warships".  This suggests a simple butt-joint to me.

 

 

Edited February 7, 2021 by Charles Green
additional information

[Don Case]

Thanks for the replies. This is where I saw it. Took me awhile to find it. Post #10   

 HMS Vulture 1776 by Dan Vadas - 1:48 scale - 16 gun "Swan" class sloop from TFFM plans - Finished - - Build logs for subjects built 1751 - 1800 - Model Ship World™

Is there something different about this area that would call for rotating the scarfs?

[allanyed]

Don,

What Dan shows in his photos is the correct way for English ships.  The forward joint is a simplified version of a boxing joint meant to tie the keel to the lower stem which takes stress in all directions at that point, thus the design.  What is not shown is that this joint in full size ships is  tabled as well and the vertical surface was actually angled slightly,  similar to the keel scarphs.  The tabling will be hidden when assembled and for our scales of models, they are not adding anything unless the builder would like to give it a go for their own satisfaction.

Allan

 

[Don Case]

Thanks Allan. Every answer(unfortunately) leads to another question. Boxing joint. I did a search and after wading through all the Mike Tyson stuff ended up at one of your posts where you were wondering if a 1690's ship should have a scarph or a boxing joint but it didn't explain what a boxing joint. I have downloaded Oxfords Glossary and find it very helpful but the drawing of a boxing joint is almost incomprehensible. Enough so I don't think I'll be trying it😃

 Figure G-11b. Scarfs and seams. | Oxford Handbooks Online

 

Just to be clear, this is not a request for more info, just a bit of a whine about the difficulty of wading through a new lingo. I'm sure you've all done it unless you were born in a shipyard. Will Langridge help with this or am I putting too much hope on one book?

 

Edit- found it here on my next search

 Fusion 360 - Page 2 - CAD and 3D Modelling/Drafting Plans with Software - Model Ship World™

Don't think I'll be trying that😃

Edited February 8, 2021 by Don Case

[druxey]

Longridge will make all things clear! (Well, nearly all.)

[Don Case]

Thank You. It's somewhere between here and Chicago and the tracking isn't working☹️ Supposed to be March 5 I think

[allanyed]

To name a few others, The Fully Framed Model, Volume I,  Naiad, Volume I, and Euryalus Volume I all show the boxing joint.  Pages 39-42 in Naiad go into a lot of detail on how make this joint with hand tools.   

 

Even on a model, especially if a POF, if there is a keel and a lower stem piece, the boxing joint really is something you need to make.  If you make some other joint, it is liable to be a weak spot and twist and turn and maybe even break when adding the frames, hawse pieces and subsequently the planking.  Plus, this joint is exposed and will be noticeable on the finished model.

 

Allan

Edited February 8, 2021 by allanyed