Re: All fixed
Re: 'The starboard stern seats are not structual at all just used as a flat material to sit on and Hunter and many others have been using starboard for tthis for many years.'
Perhaps my experience comes from the boat-repairing and boatbuilding side more than the maintaining-with-a-'that's-good-enough'-appraisal side. I have seen enough broken Starboard to know its attributes and drawbacks well.
Also, a seat IS structural-- any seat for your bottom could just as well be stood upon; and point-loading or flexing Starboard under load is the easiest way to break it. A shattered Starboard seat, or one torn from its screws, could land an unsuspecting (and perhaps injured) guest in the water. I do not applaud Hunter and other builders for using this junk for pulpit seats. I can assure you, however, that the reason they use it is not because it is 'good enough' (for it is only marginal at best, in this application) but because it is cheap to buy and cheap to install, from a production standpoint, especially when compared to using actual wood.
A piece of wood, even plywood, properly reinforced, would do the job much better and be compatible with all bedding compounds and finishes. If you insist on using Starboard, reinforce the plate with wood (or even metal angle) ribs on the bottom. Letting the screw heads show is fine so long as they are sufficiently countersunk to avoid tearing swimsuits. (Use quality screws and polish the heads first.) Screwing into Starboard from the bottom, into a blind hole, especially with wood screws, is bound to prove unreliable.
Once again, friends, be advised that advice I offer on this site is from the point-of-view of a widely-experienced builder/repairer with 40 years' experience in the business. The reader chooses to accept such expertise, or not; but please remember it is well-meant (and cost-effective!).