There is a German company that markets an auto-inflating masthead float that might keep the boat from turtling. It's not cheap but it would greatly reduce the windage compared to a solid float, auto-inflating masthead float
When I wrote a reply to your thread right above the box where I typed my response there are several editing buttons. One of them controls strike-through. Simply select the text that you inadvertently enabled strike-through and then click the strike-through button.
Edited: I tried to go back and edit my post and I notice that the strike-through button is not available when editing an exisiting post.
I stand corrected, I saw a picture on the Ronstan website that showed a lashing through the center and I incorrectly assumed that was the only way to rig the block. I too much prefer lashings, they are much quieter than shackles.
I'm pretty sure it's not blush that causes the issue. I scrupulously cleaned the cured epoxy before applying the primer but it still never dried. I've read explanations for the problem but can't explain it myself.
I have run into this issue on a build many years ago. I used a one-part primer (West Marine store brand) over WEST epoxy and it never cured. I ended up sanding all the primer off and then applied Interlux 404/414 2-part epoxy primer (now called Epoxy Primekote). The Primekote cured just fine and sanded very nicely. I thought it was a reasonably high-build primer. The Primekote is also very tough. If I were painting a new build I'd certainly use the Primekote. One warning, the fumes from the Primekote are pretty noxious. Be sure to use a good organic respirator.
I'm not familiar with Devthane so I'm not sure if it has the same handling requirements as other types of 2-part linear polyurethane paints (LPU). I do know that it is not recommended to spray 2-part LPU unless the operator has a forced air respirator. A regular respirator is inadequate.