As has been said, is there a way they can get rid of the moulded lugs and the thicker solid sections of the Mirage slot, and then have an insert. I think it was Roadrunner who said that they would then have to make them all different depths for the different models. Is it just the PA that is deeper or are they all completely different depths through the Mirage slot, I always thought that most of them would be the same as the Mirage plug always seemed to align with the decks that I looked at (not that I have looked at many).
To clarify, the Click N Go always sits at the same distance off the hull bottom so your Drive or drivewell plug always has the same reference to the hull bottom. The drivewell tongue (where the biggest stress load occurs) also sits at a constant distance from the bottom -- and therefore has a constant reference to the C&G mounts. BUT, the the top
of the drivewell, where it merges with the cockpit floor, differs with the different models.
Any drop-in insert would have to be flanged so it could distribute the tongue stress throughout the larger drivewell area. This is how the inflatable drivewell cartridge works (see picture below).
Now, if the drivewell had a built-in ridge or shelf molded in at a constant height from the tongue this might work. The ridge would go around the entire well (but would be reversed or "upside down" on the back half). It would drop in, being anchored to the C&G mount.
The problem with Polyethylene is that it migrates over time. Yes, it recovers to some extent, but after about a half million impacts (each one causing a tiny amount of flexing) it will ultimately stress to a point of cracking. Heavy users stress the tongue more -- most users don't ever reach that point in most cases. But there other factors in the process that can also affect when this occurs -- some are random and some are not.
Hobie has gone to great lengths to address this problem. They have thickened the tongue area, they use a brass insert to distribute the stress. Their polyethylene undergoes a rigorous quality control testing continuously, molding temperatures are tightly regulated. I would guess that the hulls today are at least 3 times stronger in the drivewell tongue area as they were when the first Turbofins came out. As Matt pointed out, they have made great strides.
Still, sometimes cracks show up prematurely. Hobie acknowledges this and is more than willing to replace the boat within the warranty period, even if it's not the original purchaser. So far we haven't been able to prevent tornadoes or harness hurricanes and Hobie hasn't yet come up with the perfect boat.
Foot propulsion offers a huge advantage over paddling. It also puts a tremendous strain on the vessel, channeling so much thrust through such a small area. I guess there's no free lunch. Personally, I'll pay the price -- the benefits outweigh the cost by far.
Aside from the annoyance, is it safe to use Hobies, knowing there is a possibility of getting a crack in the drivewell? In my experience with cracks, they start out small, leak a little bit and give plenty of warning as to what is going on. I have absolutely no concern about this as a safety issue. I am aware of one Hobie that sank a few years ago from a crack. The owner had identified the crack, the dealer had ordered a replacement hull, then the dealer foolishly gave the defective boat back to the owner so he could continue using it until his replacement boat arrived. He stupidly went out to sea in rough conditions, expanded the crack in to a huge rip, sank his boat and had to be rescued. Then he proceed to bad mouth Hobie for causing his boat to sink. Perhaps that's human nature.