I had a friend who is a material scientist at 3M help me out on this one.
We calculated the modulus of elasticity necessary to ensure a tight seal
along with the thicknes of the material that would be necessary without
causing difficulty in opening the front hatch. Porosity was also a concern,
as well as sensitivity to UV. We had a couple candidates for materials to
use but none were ideal in all conditions. Finally we tossed out the UV
requirement since the hatch would be covered over most of the time.
So after intense deliberations, we decided a cylindrical extrusion of a soft
vulcanised rubber could be made to meet these requirements.
Unfortunately,we couldn't get the R&D lab manager to give us time on the
automated equipment because they didn't think potter P19 hatch seals were a
big enough market ...
So I spend about $2 on a length of rubber vaccuum hose at an auto parts
store, slit one side, and installed it around the hatch opening. It works
pretty well :)
Sorry, I couldn't resist. Its winter :) The vaccuum hose part is true. :) I
honestly haven't take a huge wave over the bow since i installed it, but it
looks nice.