Confused about floor and stringer work!

Im 15 and I have a 14 ft. Ski-Barge and its got a little access type hole in the back that allows you to look in between the boat. And I noticed that it had some water and the foam stringers were kind of decomposing probably due to the fact that the boat is used in saltwater and that its like 30 years old.(lol) Plus when I step inside the boat there are some spots that crack and kinda bend inwards. I called a repair shop and the guy told me they would remove 1. Remove the floor 2. Make new stringers 3.Fiberglass the stringers in 4. then put in the new floor for around 1,500 bux. TOO MUCH FOR ME. So my questions are can and would it work for me to cut out the floor with a grinder then remove the stringers clean out the bottom put new stringers encase them to the bottom with fiberglass bondo and then put in the new floor? Where do I get stringers? How thick does the floor have to be and what type wood do i use? How would i fiberglass in the floor? And last of all where do i get a sheet of wood big enough to cover the bottom? Its 14 ft long and 5 ft wide? I know it seems like alot but i can do it i just need a little help? P.S its a center console any idea where i can get a small one?

 

You can do it. use pressure treated ply. make sure its very dry. Make sure that the stringers are set above the floor by 1/4 in. You can set them up using pieces of foam every 3 ft or so. You don't want to set up a hard spot against the fiberglass, this will cause damage to the glass laminate. Glass the floor on the sides using the same technique. There are many books on the subject. Rule #1 read and learn than proceed.