Parkers have foam injected between the stringers, below the decks. This would be best answered by Robin Parker (aka BoatGirl). This adds some buoyancy, I would imagine, but I doubt that Parkers are "unsinkable" in the Whaler sense. My guess is that if your bracketed 2530 were swamped, and the bilge pumps failed (batteries in the bilge?), your boat would become unstable, turtle, and float near the surface upside down. But this is a guess, and I would want Robin to answer that herself if I were you.
There is "coast guard required level-flotation" for boats under 20 feet. Some manufacturers adhere to this standard even in their boats above 20 feet; I am not sure if Parker does.
There is a higher level of flotation standard: NMMA. This standard adds to the level alluded to in the last paragraph.
Then there is Whaler flotation, in which the boat is designed to float LEVEL, and with THE POWERHEAD OF THE OUTBOARD above the water. This flotataion is typically measured as swamped capacity, and the higher that number the better. Boston Whaler publishes all its' swamped capacities; I wish it were mandated for all boats to do the same.
Don't get me wrong; I love my Parker, but I won't rationalize my decision to own her by saying she is just as unsinkable as a Whaler; she is not. She did cost 60% of a comparably sized Whaler though, and has a ton of other great features/attributes.
