While the individual stresses in the keel boat pattern are statically indeterminant, the joint is experiencing dynamic loading. With respect to wind, I think the leeward bolts would tend to experience relative tension; however, gravity loads would tend to mitigate that "bias". Obviously as the keel-hull joint rotates (hopefully) slightly and the sealant/adhesive does it's job, then the loading shifts.

In reality, I think the bolts and joint is experiencing variable degrees of tension vs. compression impacts on the individual bolts as it goes through a seaway.

I would liken the torquing of the boats to the equivalent of prestressing concrete tendons to get a move even pattern of loading accross the face of a section. (It's not the same for a variety of reasons, but it does reduce the differential stress and movement in a dynamic sense.)

so that the joint works more evenly accross the face. For those of you that spent some time in structural design, that would be more like ultimate vs. working stress design model.

Anyway, a bulb is not nearly as extreme as one of those 13' deep, pure bulb fin keels, with a very flat bottomed hull. They must take much larger relative bending loads (i.e., more differential tension vs. compression) on that hull-keel joint.

When a boat goes off of wave and "slams" into a trough, even worse when it lands in a trough at an angle it makes a lot of these stresses worse because they involve accelerations (which increase the stresses well beyond simple static force diagrams). That's why the adhesive's elastic capabilities are as important as it's adhession.

There are obviously relative design challenges. Extreme designs (like those long, deep "stilleto" with a massive bullet bulb) require extreme care. A lot of would agree that extreme anything has its perils and better be justified on critial components.

I have a modified (pretty innocuous) bulb on our J/Boat. We havea keel to hull joint width and relative long lenght that looks pretty "normal" with regard to her hull-to-keel joint. She is a fin keel, but not an extreme one. The induced moment on the joint of hitting a ledge with her 'shaol' 7'-3" vs. 9' whatever deep draft obovious depends on whether its the "tip" of the keel that hits the granite or middle of the face. ;^((((. I don't view her keel design as "extreme" -- other's with a very traditional long, wide, tapperd keel might.

On your boat, Jon, a number of people used (and still say) that an unstayed rig is pattenly less safe than the conventional stayyed rig. That's proven not to be the case over time. (In fact, I can't recall an unstayyed rig that people have had come down -- of course, if the boat didn't come back, who knows? ;^)))) In reality, I think that there are other reasons to prefer one design over another, but the likelihood of failure is not a result of simply having a stayed vs. an unstayed design.