Well the deck is very flat by design. I'm like you, it seems like it should have some sort of curve to it. Currently though it's mostly flat with some high and low spots here and there.
It's strange because the guy did a beautiful job on the hull, and somehow he must have just forgotten to read the book on how to lay a deck
I have to repair the edges where the deck meets the sides of the hull. It had some rub damage and chipping from the hurricane
as well as having most of the railing ripped off.
My plan is to drill some small holes into the sides vertically and then tie into the existing rebar. Then I'll have some steel
plate cut into long straps and make a new edge for the railing to bolt into (current setup was bolting into a concrete lip). Finally I'll use a form to cover all this with new concrete to seal everything up.
Once that is in I'll have an edge and then the self-leveling stuff should work well. I'm not using it for strength since the existing deck is fine in that regard. I just want it to get rid of the waviness the deck has in spots and to seal things up.
I figure I'll sand down the sides about two feet down, then once everything is tied back in together I'll use a good 10 year concrete sealant
I'm going to cap the new lip of the hull in trim wood to both protect the concrete edge, make it look nice, and provide the edge for the decking material I'm going to lay down.
Final thing is going to be wooden decking material over the whole thing. The stuff I found is pretty nice and gives you a cool pattern. It's tested and warranted for use on boats and glues to concrete. Plus there's going to be very little cutting so it will be something I can do myself and still get a nice result.
Here's a pic of the stuff I'm planning on using:
It's actually sold in the pieces like this. So it goes down a lot like tile with the pattern matching up till you get to the edge. It's only 3/4 inch thick, so shouldnt be too heavy.