: I was curious about what would happen if you waited too long to put the next
: coat of resin on so you didn't have a chemical bond and you didn't sand it
: for a mechanical bond. Would it delaminate?

Probably not, but there could be some small areas affected over time, if they were stressed the wrong way. You have a lot of "texture" from the weave of the fabric that would give additional coast of resin a good grip, even with out the sanding.

If you have ever tried to remove dripped epoxy from areas where it did not belong you would see how strong that stuff can bond to areas that are NOT "properly prepared"

But, you'ld be foolish to not clean the boat before putting on a layer of resin, if it had been sitting for a while. So, instead of cleaning with just a damp cloth you go over the surface with a sanding block. This shouldn't take more than 10 extra minutes and you'll remove extraneous scum that you wouldn't want to forever embed in your resin, anyhow. Then a quick wipe with a damp cloth picks up the sanding dust and other scum and dries in seconds.
Why not spend this short amount of time to improve your chances at a good job?

Hit a rock fast enough and hard enough and you will dent, ding, or damage your boat. The amount of damage is variable and usually can not be predicted. So planning for accidents is kind of an art rather than a science. You hope to hit a dull rock at a low speed and to slip off of it without damage. Sometimes that works and othertimes you scratch through the glass cloth. Experience over the years has shown that boats built according to the plans of their designers are extremely rugged. Other experience has shown that duct tape can cover most damage, and keep out the water for a week or more.

hope this helps

PGJ