Thanks everyone for the helpful suggestions and the great photos and thanks Ebb, I did search the site for all of the words that I could conceive might lead me to photos of this area. I will now search through the compression beam and bulkhead posts. This accident is not something that I can discuss at this point since it involves other people and a clam that I may have to file.

I can say a couple of things. I think that when my boat was tabernacled, the previous owner found some delamination beneath the old mast step. He told me that he had added epoxy to the area, and based on other work done on the main deck, I assume that he probably drilled a few holes and pumped epoxy into the voids. That would make more or less a solid section beneath the mast, and strengthen the support of the mast, but of course epoxy does not compress like balsa wood, so a severe shock load (such as one placed squarely in the very center of the mast head fitting, such as running your mast into a concrete bridge member while it is partially lowered in a forward direction) for example would tend to transfer considerable force both downward and aftward, and this might (for example) send offset lateral transverse fiberglass cracks across the deck surface, force the mast step mounting blots through the cabin liner, causing the liner to buckle, and possibly crack the strong back, depress the top of the door frame and separate the door posts and other support members below deck from their intended secure bonds etc. (for example).

So I am very well aware that removal of the mast and destructive testing of the various elements of the support system will be required beffore repairs can be initiated. The extent of the damage will dictate whether a complete new support system will be installed, or whether the stainless steel brace approach will suffice. I am interested in handing to my surveyor some examples of the fine work that members of this forum have done to deal with cumulative trauma to the strong back so that we might consider them for the accident repair task ahead. The photos that you have posted will greatly assist me in this effort. The more photos, the merrier. And yes, I will be posting some photos by and by.