I believe my transom is pretty rotted. I want to replace with a Seacast transom. Anyways, I need guidance on removing the cap of the boat. How do I go about doing that. I see a bunch of dots that look like rivets. See photo. What are they. How do I remove the cap?
We need much more info about the boat make, model, year and power train (Inboard, Outboard or I/O)
What symptoms led you to believe that the transom is compromised? What did you do to verify your suspicions about the transom; did you take core samples or tried to flex it by standing on the engine (or outdrive) and see if the transom is flexing?
Not every transom job requires removing the cap, why do you think you need to? The rub rail is attached to the hull body with rivets and bolts. Not all rivets are connecting the cap and the hull. In other words, some rivets are attaching the rub rail to the cap only and it has nothing to do with attaching the cap to the hull. So, if you drill out all rivets, you could be creating more work for yourself than you have to. If you must remove the cap, find the rivets that passes through the two halves of the boat and remove these along with the bolts, of course.
SeaCast is a great product and if you want to use it, by all means go ahead. It will require some prepping though and we can talk about what is required when you tell us what king of boat you got. Post more pictures of the boat overall and the transom area specifically from both inside and outside.
Did you perform any inspection of the stringers, deck and bulkheads?