I am building a small stitch and glue boat (15' along the gunnels) and
would like some darker colored gunnels than the standard white oak. I
have been considering black walnut, African padauk, south American
mahagonay, hickory, and purple heart.

Hickory is in the list because of it strength, and shock resistance,
but I also know it is hard to work with and will be difficult to glue
(I will be glueing with epoxy).

The padauk is my leading choice. It appears to have a nice color,
decent workability and glueing characteristics, and is very strong and
stable.

Any reasons I should consider other woods and stay away from any on my
list? What are the weaknesses and merits of these woods in a boat
building application?

Thanks in advance!