Hi everyone! Many a google search have led me here (because you guys really know what you're talking about!) but for once, I just can't find an answer because no one has asked an identical question... so here I am!
I have a 1984 US Yachts 25. It's always been good to me and has been rock solid. However, I skipped a sailing season last year, so it has spent two consecutive winters on its trailer (a flatbed trailer with a cradle attached to it, basically).
Now, there are two large 'dents' in the hull where the rear supports are. This probably formed last winter when the cockpit became flooded with water and froze, creating a huge weight in the stern area. I didn't notice the dents until a week ago, while tearing out the cabin which I intend to redo. There is only one bulkhead near the dents (which are around 18 inches in diameter, the port side being more prominent) and it isn't even tabbed except in two small spots, and I can now clearly see it doesn't fit the hull shape anymore. I should mention now that the hull is *solid fiberglass*, so this shouldn't be a matter of delamination. It is also bone dry, and there are no cracks that I can see.
I've heard it numerous times that this 'oil canning' effect is common and not a problem, as the fiberglass either return to its original shape or will stay that way.
However, what I haven't found online yet is someone explicitly mentioning that the area is now *soft*. I jacked the boat up by the rudder so it was just off the supports. The hull in general is completely stiff, but these indented areas are around as flexible as say, a car hood. Not spongy or anything, but you can visually see the are bend in if you put pressure on it.
What does this mean? I'm worried sick