I installed the fillet under the cockpit coaming on my Wood Duck 10 today and when I looked at it just now I see that in some areas it did not extend up to the top layer of the three layer coaming. (See attached photos.). Should I add some more fillet to extend fully to the top of the coaming spacers or will the epoxy take care of things? Also, if you recommend I do install more fillet, should I do it within 24 hours of the initial application? Also, how much fillet should I install? Enough to extend over a portion of the bottom of the top layer of coaming? Thank you in advance.
Yes, you should add more fillet material. The fillet is what transfers forces between various parts of the coaming. If it does not perform a smooth transfer, then the components will not share the forces properly and one or the other could be overstressed and fail.
For a fillet to do its job, it must be smooth with continuous coverage and no discontinuities. Discontinuities act as stress concentrators and can make the result worse than if there was no fillet at all. In fact, the whole point of that coaming fillet is to get rid of the stress concentrator formed by the coaming resting on the risers at a 90 degree angle. So do fill it in and smooth it out.
I realize that it’s too late for this boat, but for your next one you can make the filleting easier by building up the coaming on a plastic sheet on the deck, removing it to add the fillet and sand it, then mounting it permanently on the deck when done.
Laszlo
Thank you very much. Off now to add more fillet.
Diane