scarf joints on deck

[georgeband]

Many drawings and references show scarph (scarf) joints on the deck planking for the stronger, more important planks. The waterway by the bulwark is one, the binding strake outboard of the hatches is another. 

 

The shape of a hooked scarf joint is well known and the proportions for the lengths of different sides can vary. A paper by Karolak et al describes many of the variations on scarf joints Karolak scarf joints.pdf. Current use in boat building are described in a short article by Souppez  https://www.woodenboat.com/strength-scarf-joints. I guess that around 1800 in the Royal Navy or elsewhere there was a conventional way to draw and cut the joint so that it is not too long or too short. Does anyone have a contemporary description of the relative sizes? I think back to learning how to make a mortise and tenon joint at school where the join is one third of the width of the wood. There must have been something similar, though more complicated, for a scarf joint. 

 

My second question is about left-handed or right-handed joints. Drawings in three books I have all show that the aft timber extends farther forward on its outboard edge; the fore timber that goes into the joint extends farther aft on its inboard edge. Was there a conventional way to align the scarfs or was it the choice of the shipwright?  I have not yet found any contemporary evidence. 

 

I will continue my searches on Google and ask for advice from the wise people who have looked at this before. If there is no evidence anywhere then I will simply choose a joint shape that looks good. 

 

George

[druxey]

Usually scarph lengths were three times the width of the plank. Generally speaking, the direction was such that the wood that planks (or framing elements) were being cut from were as long as possible with minimum waste. So, on a curved piece, the tip of the scarph would usually be to the concave side.

[georgeband]

Druxey,

 

Thank you for your quick reply, appreciated as always. 

I did not explain my problem properly and have now added a sketch to illustrate the point. I should have done this at the start to make it clearer. 

 

 

The sketch is not an accurate depiction of a hooked scarf but represents the choices I have to make. For the waterway I will be joining an edge-bent plank (aft) to a spiled section (forward) and there is sufficient overlap between the pieces to make either option, A or B. If I choose on aesthetics alone then A looks better to me (at the moment). The join on the binding strake will be handed in the same way as the the one on the waterway just because it looks neater. 

 

I enjoy the research on these issues but it is possible to get so engrossed in a search to ensure accuracy that a model does not get finished. Perhaps the only model which can be perfect in all respects is one of a subject which still exists, and the model represents her as she is now. Victory, Cutty Sark and others form a small band but the vast majority of ship models are reconstructions based on best available evidence. Sometimes we rely on informed guesses. (I have just found and enjoyed the thread you started about research.) 

 

George