Re: type of wood for decking?
Welcome Aboard..
Do a quick forum search, using the above SEARCH menu...Type in replacing deck or any such verbiage and you will see a LOT of info..I mean a LOT!
He's right.. Tons of info on it. You will be totally confused.
1. Be practical. It's an 88 are you gonna keep it forever?
2. Do you run in Salt water.
3. Does wood in your geographic area rot quickly?
If the answer to all three is yes, then 5/8 to 3/4 ACX plywood sealed and glassed is a good choice.
If you answered no to all three you can just use 5/8 to 3/4 ACX and two coats of a good Spar varnish. First coat thinned 25% for penetration and second coat unthinned.
As a side note, you'll get an extra layer of topside protection if you use a spread on water proof exterior glue to put down your carpet or vinyl. Also, adding a bilge blower will help to dry it out before you put it in storage. If the boats dry when you store it, your decks will last much longer.