: Couple advantages to a scraf joint, one it's pretty strong assuming
: it is long enough, usually at least 8:1 and often up to 12:1,
: length vs. thickness.

: The big advantage is, done correctly, the scarf doesn't adversely
: effect the bending of a piece of wood, so the scarf bends
: naturally just like there was no joint in the wood. A lap joint
: will end up with a hard spot that'll tend to straighten the bend
: where the joint is.

: Bill H.

Done well a lap joint can be virtually invisible from one side, but a scarf joint is looks just as good from either side.

A lap joint doesn't have to be very long; a butt block 7 to 8 times the thickness is enough to provide strength equal to the material, and a short flat spot is less likely to show. Location is important too: avoid the most sharply curved parts of a plank, hide butts under the deck or at a bulkhead, and in many small boat designs the planks are often less stressed near the stems than midships so the flat spot hardly shows.