You probably don't want to be much sharper than 5mm (3/16") You might actually want to sand it down and make it a bit smoother so you don't have any problems wrapping fiberglass around the bow. I don't think you'll notice any difference in speed between 5mm, 10mm, and even 15mm. You might see a tiny difference with a 20mm bow, but probably not even then.

Shawn

> How sharp shall I make the bow. My glassfiberkayak is almost 20 mm in the
> bow but that seems to be to much for a stripbuilt kayak. I am using 4.5 mm
> strips and that gives the bow a width of about 5 mm. Is it to sharp? I
> suppose it´s a question of speed visavi strength. Fritjof