Maybe a silly questions, but I need a do-it-yourself boater's opinion

[SkyChimp]

I've got a Tracker Grizzly 15' aluminum jon boat with a front deck and chair pedestal base.



I'm going to remove the pedestal base and overlay a precisely cut piece of carpeted plywood on the deck, and remount the pedestal thru the new deck. I'm doing this so I can mount accessories to the new top deck instead of to the underlying aluminum deck.

My plan was to use a 1/2 piece of pressure treated plywood.

Here's the question that may sound silly: pressure treated plywood is treated with a copper salt (copper gives it its green color). Since the wood contains salt, and it will be making direct contact with the underlying aluminum deck, should I use pressure treated plywood? Is this concern silly?

Thanks!

[PanMan_VA]

You can paint the wood or wrap it in a layer of fiberglass if you are concerned about galvanic corosion.

[SkyChimp]

As far as I know, you can't get arsenic treated wood anymore. I understand that it out of production in favor of copper treated wood, which is both insect and rot resistant. In fact, you can get copper pressure treated wood that is submersible in salt water - like pilings.

The problem with pressure treated wood is that it's corrosive. You are supposed to use stainless steel or galvanized hardware with it. Now that I've thought about it, it seems that a piece of this stuff lying on an aluminum deck might not be a good thing.

[CrappieHead]

A small word of advise. Do not just use pressure treated plywood (also called CCA plywood). Use a Maine grade plywood.
CCA plywood from what I understand does not use a maine (waterproof) glue to hold the sheets together. Maine grade plywood uses a waterproof glue. Maine grade plywood is allot higher priced. I priced a sheet of 3/4" maide grade plywood some time back and I think it was over $50 a sheet.

[Shellback]

From what I understand, you should not use pressure treated where it contacts aluminum. I'd rather use exterior and 2 coat it completely with a waterproof glue. That's what I've done. Rather replace the plywood than an aluminum deck.

[Mopar Matt]

A CCA treated plywood will work, it has an exterior glue but it is not rated for water submersion like a marine grade of plywood. CCA treatment has been discontinued since Jan 1 of this year so finding some might be a challenge. It has been replaced with ACQ treatment process and the ACQ will corrode all metals except for stainless (and the stainless testing is yet to be finished). I personally would use a new age OSB (like Advantech) they are rated for water submersion and most have a 50 year warranty. They are also a good bit cheaper than a marine grade plywood.

[Kokanee King]

Go with the marine grade it is a bit more exspecive but it is worth it, then go ahead and wrap it in vinal to make it pretty.

[Wardy]

Not sure you are going to be able to mount things with out getting into the original deck. If you drill a hole in the plywood, are you not also putting a hole in the deck?

[Big Dave 53]

I just read a tag from some pressure treated lumber I got at Home Depot and it specifically says to not to place in contact with aluminium...how about marine grade plywood???

[SCOUT]

I extended the deck of my 15' jonboat and used some left over osb sub flooring from my buddies new house. I dont remember the brand name but I was told it was submersable, it could have been advantech like matt was talking about. I was a bit leary about it so I painted it with some left over fiberglass epoxy resin that I had from building a duck boat. It has held up for a year now and is as good as the day I installed it.