the bottom of the hull looks pretty good I would how ever like to know how to dewater a foam hull as that may be good info to know. I have turned down some good deals on Carolina skiffs and whalers in the past for saturation problems.
Well it isn't a quick fix to get rid of the water trapped in the hull, but I can give you the quick version of a fix.
Imagine a boat with just one hull layer. When you pick up the bow of the boat with water in it, the water will flow to the stern at the lowest point, which is normally the keel, on most Whalers, they have a tri-hull, in your case the jet divides the back of the hull into two sides with the jet system in the middle.
With the boat on the ground, look at the back of the boat and you can see where the low points are at. Take a drill (about 1/2") and put a hole in from the back or bottom of the hull's skin (one on each low point for starters, more if needed). Then raise up the bow so that the water in the foam will start to migrate to that lowest point, it may take a few months, so don't plan on using the boat for a bit!.
"DO NOT" use air to help push out the water, just a half a PSI can cause the hull sections to inflate and rip apart the foam bonding samwiched between the two fiberglass section ruining the strength of the hull!
Once you have drilled the main hull holes, take a long 1/4" type rod and poke it up into the foam inside the hull, this gives the water a place to drain to and allows it to drain out of the boat much quicker. Just push the rod up one or two directions, that will be all you need to do. Then wait until the water stops dripping out of the holes.
Once the water stops dripping out after a few weeks/months, then you will need to mix up a fiberglass resin, sand out the hole with a small file, mix up some shreaded fiberglass matting, mix it with the resin and poke in into the holes to perminatly plug them and stop the water from going back into the hull. It would be a good time to patch the hole that caused the water to leak into the hull in the first place as well if it is not already done.
You can buy jelcoat resin that is the same color as the boat hull and use that to make the hull all one color if it is important to you, if not, it will be underwater and nobody will see the patches.
That is the short version, and done if you have a water logged hull from a damaged hole in the hull. You can have up to thousands of pounds of water in the hull's foam depending on what size the boat is, not to mention it won't have much floatation if it is waterlogged and will use a lot of gas to get going anywhere because of the excess weight.
Hopefully, your boat is dry and that isn't an issue, but if it is waterlogged, you want to remove the water before it freezes in winter, that will also tear up the foam/fiberglass bonding internally as well from freezing and expanding.