Without the wider bunk, if the hanger lets go (though I don't think this is a common failure, is it?), the whole thing is still kept from dropping by the cleated pendant only. 'Course, the pendant is supporting the entire weight, which it's not designed to do. If the pendant goes, the board's gonna drop.
If a wider bunk is wide enough, it seems as if the board would be held in the trunk even with a failed hanger and pendant.
I wonder, if you managed to launch the boat with a failed hanger, what happens when you unsuspectingly uncleat the pendant to drop the board? The pendant unexpectedly whizzes though your hands and gives you rope burns, so you let go. The board drops out of the trunk entirely. Then the knot in the end of the pendant catches the cleat, but the momentum of the falling board and the force on the board from the current due to your boat's forward motion rips both the cleat and the turning block out of the deck. Everything eventually fetches up against the little loop fairlead at the top of the compression post. That gets damaged as well, just before the knot on the end of the pendant breaks, everything goes overboard, and the CB sinks to the bottom of the ocean.
This is beginning to sound like some fictional disaster from the Darwin awards, so I'll stop now.
Seriously, here's the guaranteed best solution:
A wider bunk, notched in the center for the CB, with a plate and spacer screwed to the bunk from underneath. The plate and spacer stay in place all the time until you want to drop the CB. At that time you just unscrew it and the CB will drop right out. Don't put your face under it when you do it.
