Thread here may help with how to attach them:
http://www.kayakforum.com/cgi-bin/Building/index.cgi/md/read/id/197612/sbj/paddle-adding-hardwood-tips/

I ended up getting some (cheap) Loctite marine epoxy, putting a seal coat on both surfaces, and then epoxying together once the seal coat cured.

: I have an old paddle with severe tip wear - it didn't have hard
: tips and is starting to delaminate; soon it will need surgery.

: What is the best wood for tips? I have oak, cherry, ash but no
: maple, although I can get some. How are the tips fastened to the
: paddle: should I use a mortise, biscuits or will simple dowels
: do OK?