Hi I'm new to the forum, I have a 17ft flyer with a 40hp mariner and have a problem with it, since I have owned it it has always been slow and uses a lot of fuel at first we thought it may have been a engine problem but It seems to be running absolutely fine. I then noticed that there's a crack in the cover of the inspection hatch at the rear of the floor I took the cover off and it was full of water it also looks to be foam filled, could this be my problem? I have sucked the water out with a wet vac and it keeps refilling but I kept doing it until no more water came out. I am new to working on boats and do not no a lot so any help would be greatly appreciated. Thanks Ash.