stupid question?

[a1999ponyboy]

i notice that most of the guys on here use regulare high grade ply wood when doing floors and stringers, then wrap it in fiberglass? do you have to do this with marine ply? when i was in iraq we had marine plex to build floors in our tents. it was plywood with an extreemly hard dark brown coating on it. is this marine ply? every where i have looked online marine ply looks exactaly like regulare ply. sorry im a new guy.

 

[jigngrub]

Re: stupid question?

The plywood you had in your tents was HDO (high density overlay) or MDO (medium density overlay) plywood, waterproof and very durable.

The stringers need to be wrapped in glass and tabbed to the hull, but you can just coat the deck in epoxy resin.

 

[a1999ponyboy]

Re: stupid question?

this is the stuff here
http://besthongsen.en.made-in-china.com/offer/TbgnpSHVvzkf/Sell-Marineplex-Filmfaced-Plywood.html

 

[Raystownboater]

Re: stupid question?

Marine plywood will not guard against rot................there are very little (if any) voids in the layers vs other plywood so you still need to encase the wood in epoxy or glass it in

 

[a1999ponyboy]

Re: stupid question?

ok so is it worth the money to get marine ply or just get a high grade ply? also do you tab the top of the floor to the hull? another stupid question....... how do you secure the floor to the stringers?

 

[Raystownboater]

Re: stupid question?

You don't have to tab the floor to the hull but you need to encase the deck in epoxy or polyester and fiberglass. With that said, you don't necessarily need to spend the extra money on Marine plywood

 

[a1999ponyboy]

Re: stupid question?

ok but once you encase the wood in fiberglass or reson you cant put screws threw it to seure it to the stringers right? because your now putting holes in it for water to wick in?

 

[Ciera2450]

Re: stupid question?

Screw it down, then glass over the screws.

 

[Woodonglass]

Re: stupid question?

If you predrill your holes, then fill em with resin and coat your screws in resin and then glass over em the deck will be there for your Grand Kids.

 

[a1999ponyboy]

Re: stupid question?

thanks guys

 

[jigngrub]

Re: stupid question?

Just remember, resin and fiberglass holds water in the wood just like it holds it out of the wood... and whenever you penetrate that barrier with a fastener without a sealer, there's a potential leak into your encased decking with no way to evaporate out. That's why you see so many people on here replacing rotten glassed in decks.

 

[Decker83]

Re: stupid question?

ok so is it worth the money to get marine ply or just get a high grade ply? also do you tab the top of the floor to the hull? another stupid question....... how do you secure the floor to the stringers?

If you are putting this floor in a fiberglass boat I would tab the top side of the deck to the hull. I would use PB to around the edges where the deck meets the hull then tab with 1.5 CSM and 1708 biax.

If this is a tinny then no tabbing.

 

[109jb]

Re: stupid question?

You don't have to tab the floor to the hull but you need to encase the deck in epoxy or polyester and fiberglass. With that said, you don't necessarily need to spend the extra money on Marine plywood

I disagree. You need to do what was originally done on the boat from the factory. If the deck was tabbed to the hull from the factory then it needs to be tabbed to the hull.

As for plywood, My Sea Ray had what appeared to be regular CDX plywood with knot holes in the outer ply on one side and the football shaped patches on the other side. This was the factory installed deck. I decided that if it was good enough originally that I'd just replace it with CDX. The problem I found with CDX is that it warps like a pretzel and you have to figure a way to straighten it. For my project, once screwed to the stringers it was straight fore-aft, but not side-to-side. I used straight pieces of 2x4's cut to fit cross ways at a few spots and screwed them to the deck (make sure not to penetrate the hull). This held it straight and I tabbed it to the sides of the hull everywhere except where the 2x4's were. Then remove the 2x4's and finish the tabbing at those spots.

 

[oops!]

Re: stupid question?

You don't have to tab the floor to the hull

yes......you do.

the deck is a major structural part of the hull........the deck ties everything together.........glass it all down.

im not going to go into boat building 101. but the above is the way to do it

 

[a1999ponyboy]

Re: stupid question?

lol ok another stupid question? what is pb?

 

[ezmobee]

Re: stupid question?

You don't have to tab the floor to the hull but you need to encase the deck in epoxy or polyester and fiberglass. With that said, you don't necessarily need to spend the extra money on Marine plywood

Todd, your aluminum is showing.......

 

[kahuna123]

Re: stupid question?

The reason to tab is to spread the stress over a larger area. If you don't you will create hard spots that do not flex while everything around it will. You will have stress cracks if at not some point failure. Especially on these thin hulls.

Did I buy high quality plywood at $70 a sheet for my sons $500 boats new transom?? NO

 

[a1999ponyboy]

Re: stupid question?

great got it, so what is "PB"?

 

[Woodonglass]

Re: stupid question?

It is Thickened Resin used to fill gabs and cove joints allowing the glass to lay down easier.
This is a great video on how to make it.

http://www.youtube.com/user/FriscoJarretts?blend=1&ob=5#p/u/34/N3kmr9ZctUo

 

[a1999ponyboy]

Re: stupid question?

ok so when i do the new floor and stringers, im thinking im going to use a poly resin. im assumeing that the boat hull was made wuth polly? plus the polly is much cheaper! any thoughts?