: I'm about three quarters done with my rib mortices and I have to say it's a
: little hair raising. They aren't that accurate. My holes are a little
: outside the marks - side to side. I've planned to use epoxy on this boat
: all along. I will probably end up putting a dollup of epoxy in each
: mortice when installing the ribs. I'm thinking a little paste wax on each
: rib will stop them from being permanently glued into the mortices.

: The picture is a drill guide that is supposed to give a uniform depth and
: hole spacing.

Chip,

The image below is of Maligiaq Padilla, the five time Greenland champion, cutting the mortises for the gunwales, he follows the same procedure for the rib mortises -- three holes side by side excavated with a sharp chisel. Depth gauge is simply masking tape wrapped around the bit. I cut mine the same way but used a bit-brace to bore the holes (quiet and slow although easy it control).

Svend Ulstrup and similar instructors often have their students cut these mortises with a sloyd knife. Perfection isn't required, you aren't making furniture. Many kayaks in Greenland have deck beams or ribs that rattle slightly in their mortises until lashed or pegged. As others have said, the lashings and skin will solidly tie the assembly together. This is a very forgiving type of building method.

Greg Stamer