# Question about using PVC instead of plywood for transom...



## delaney (Aug 4, 2011)

I am a complete and total noob when it come to boats, but recently purchased an 14ft aluminum 1952 Sea Nymph, 25hp motor and trailer. The boat is a little rough and the first thing I need to do is replace the transom. instead of using plywood has anyone used or thought about using pvc instead? The link below is to a site I found that is advertising weather resistant PVC.

Any feedback?

https://freckleface.com/shopsite_sc/store/html/product370.html#370


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## spg (Aug 4, 2011)

Not at those prices [-X [-X [-X . A decent sheet of ply at the local borg will only run around $50 a sheet.


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## jigngrub (Aug 4, 2011)

I'm sure that stuff would do a nice job and never rot... but your transom material is more than likely 1 1/2" thick, so you would need 2 pieces of 3/4"... and you can get a whole sheet of kiln dried CCA pressure treated plywood for $75 with shipping included. The 4x8 sheet will give you more than enough material and will probably outlive your boat if installed correctly.

Here's a link for the plywood.


https://www.pontoonstuff.com/pontoon-boat/144-marine-plywood.asp


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## Ictalurus (Aug 4, 2011)

jigngrub said:


> and you can get a whole sheet of kiln dried CCA pressure treated plywood for $75 with shipping included



[-X [-X [-X [-X [-X 

Stick with exterior plywood, coat it three times with spar urethane, keep it out of the elements when not in use and it will outlast you.


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## jigngrub (Aug 4, 2011)

Ictalurus said:


> jigngrub said:
> 
> 
> > and you can get a whole sheet of kiln dried CCA pressure treated plywood for $75 with shipping included
> ...




If you click on the link you'll see that this is a marine grade plywood used for pontoon decks and others. It has fewer (almost none) voids which means it's stronger and a sanded side for decking applications. It is the Cadillac of marine plywoods.

My Tracker Deep V came fom the factory with this plywood installed, and it's really too bad that many people don't know about this wood or are too cheap to use it... it is a high quality product.


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## delaney (Aug 4, 2011)

Ok thanks for the info. Plywood it is.


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## BassBlaster (Aug 4, 2011)

jigngrub said:


> Ictalurus said:
> 
> 
> 
> ...


This particular plywood was discussed in depth recently. The conclusion was it will still corode aluminum. Not as fast as typical pressure treated lumber but it will still corrode. Manufacturers use this stuff because it is labeled as "safe for aluminum contact". My guess is it still wont last as long as exterior grade ply with Spar Urethane coatings. It would cost manufacturers more money to treat regular ply so buying the product your pushing is cheaper for them. Still dosnt make it the best option.

Edit...Okay , I was wrong. I guess I should have clicked the link before assumeing it was the same as what was recently discussed. So they claim this has arsenic in it rather than copper so it wont corrode your boat. Insted it will just kill you, lol. There is a reason the EPA banned that stuff years ago.


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## jigngrub (Aug 4, 2011)

> Edit...Okay , I was wrong. I guess I should have clicked the link before assumeing it was the same as what was recently discussed. So they claim this has arsenic in it rather than copper so it wont corrode your boat. Insted it will just kill you, lol. There is a reason the EPA banned that stuff years ago.



They banned the arsenic formula PT because a very few people were having reactions to it from walking on it in their bare feet when it was installed exposed for decking and such. 

It is still approved for marine use because it is covered with glue and carpet, vinyl, or encapsulated in between layers of aluminum like transoms and such.

The new ACQ PT lumber is still toxic (it still has to kill the bug that tries to eat it), but just not *as* toxic as the old CCA formula. The new ACQ formula has much higher levels of copper in it and that's why it corrodes aluminum. The new ACQ PT wood still shouldn't be burned and scraps may be considered toxic waste in some areas.


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## Ictalurus (Aug 4, 2011)

It seems that once every six months or so someone starts the talk about the new PT wood, last time I think it was a salesman (haven't seen a post since the PT discussion). Bottom line is it's your boat and you can put whatever you want in it. For me the choice is easy, exterior grade plywood with several coats of spar urethane, I don't think you can go wrong with this route.


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## jigngrub (Aug 4, 2011)

Ictalurus said:


> It seems that once every six months or so someone starts the talk about the new PT wood, last time I think it was a salesman (haven't seen a post since the PT discussion). Bottom line is it's your boat and you can put whatever you want in it. For me the choice is easy, exterior grade plywood with several coats of spar urethane, I don't think you can go wrong with this route.



*IF* you know what you're doing it's all a matter of personal preference and it isn't a problem... it's the people that don't know what they're doing that have the problems.

There's a lot of people that're absolutely convinced they need to wrap their plywood in fiberglass and resin to preserve it, but I've seen just as many glassed in decks rotten as other methods of preservation... but I can't remember ever seeing a single CCA PT deck rotted.

Urethane and fiberglass are great... until you breach the barrier with a screw or bolt hole, then the covering works against you when water infiltrates the wood. The urethane and glass will hold the moisture in just as well as it keeps it out when when the wood doesn't have any holes in it.

I'm not hear to say urethaned CDX is bad, I'm just saying there's another option.

The CCA ply comes with a lifetime warranty, that should tell you something.

I learned a long time ago, there's as many ways to do something as there is people to tell you how to do it.


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## Zum (Aug 5, 2011)

I think all your posts are on this subject.
You can't remember ever seeing a CCA PT deck rot,banned arsenic because a very few people were having a reaction,seems you have some answers.Doesn't old rat poison contain this stuff,illegal now.
You wouldn't be a salesperson would you?

I'm sorry if I come on alittle strong but it is arsenic(real bad stuff,google it) and I think it still has alittle copper in it(green)another reason to stay away from aluminum.

If you do decide to use it,DON'T burn the scraps(illegal in all states),wear mask,gloves,fingers out your mouth,cover it with something so you don't stand on it directly,etc.
Other then that,probably last a long time...just like the arsenic thats in the wood/soil,where it was used until banned.
Just an uneducated mans opinion.


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## JustDucky (Aug 5, 2011)

Why go with wood that won't rot but _could_ kill you in a number of horrible ways (https://en.wikipedia.org/wiki/Arsenic_toxicity, https://en.wikipedia.org/wiki/Arsenic_poisoning) and _will_ someday leach poison into the environment when you could go with wood that won't rot and is non-toxic. And for the deck you could just obtain scrap sheets of aluminum (try craigslist) which will certainly not corrode and will last for many lifetimes.


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## jigngrub (Aug 5, 2011)

Zum said:


> I think all your posts are on this subject.
> You can't remember ever seeing a CCA PT deck rot,banned arsenic because a very few people were having a reaction,seems you have some answers.Doesn't old rat poison contain this stuff,illegal now.
> You wouldn't be a salesperson would you?
> 
> ...




Well you must not be as educated as you think you are, CCA plywood is still leagal to use in the boating industry or they wouldn't be able to sell it now would they?

There's no telling how much CCA treated plywood you have walked on and played around as a kid... and you're still alive!!!

They only changed over the the ASQ formula in 2002, so unless you're only 10 years old you've been around it plenty of times... and even kids 10 and younger are still exposed to it from structures that were built before 2002.

I'm in no way associated with anyone that sells CCA plywood, just trying to help the brainwashed folks out there that there's another way that's probably better.

If you'll actually *READ* all of my other posts you'll see I'm trying to help people with other stuff too.


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## jigngrub (Aug 5, 2011)

JustDucky said:


> Why go with wood that won't rot but _could_ kill you in a number of horrible ways (https://en.wikipedia.org/wiki/Arsenic_toxicity, https://en.wikipedia.org/wiki/Arsenic_poisoning) and _will_ someday leach poison into the environment when you could go with wood that won't rot and is non-toxic. And for the deck you could just obtain scrap sheets of aluminum (try craigslist) which will certainly not corrode and will last for many lifetimes.



... and why don't we just use a solid 1 1/2" thick plate of aluminum for our transoms (try craigslist) for our transoms?


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## Zum (Aug 7, 2011)

Pretty sure I typed uneducated but hey maybe your right...again.
It's to bad that some stuff we use and have used in the past(not just arsenic),take so long to kill us and some of the other side effects are probably never really known.Studies take long times to get results and theories get proven wrong all the time.
I just pesonally wouldn't use an arsenic/copper based product,if I had other choises.

I'm sorry if I offended you.
I do see you are offering other advise as well and I hope you continue to do so.


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## jigngrub (Aug 7, 2011)

No offense taken in any way Zum, I got thick skin.

I look at it like this, there are so many things in our enviroment that're already going to kill us... what's one more little thing?

I really do enjoy working on my boat, but I don't want to have to replace rotten decking or transom. 

I'm fixin' to take the decking up on my boat and replace some nappy (cheap) carpet that I installed about 6 yrs. ago. I'm going to install the Nautolex marine vinyl this time and see how that goes. I'll take pics and post in the conversion modification forum for all the members. I'm going to do it different than most people would so I might catch some flack about that too. :LOL2: 

Have a good day!


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## MoHops (Aug 7, 2011)

Okay. Well I am a lumber salesman and slept at a holiday inn last night so I have a little knowledge of the gtuff. First of all, the PVC product is considered non-structural and has a tendency to crack, shatter , break, etc. so it would be terrible for a transom application. Also FYI composite deck boards are considered non structural as well and have tons of flex (another no no).

Now on to treated. CCA is still around. It can't be used in residential applications but is still available for agricultural uses and I believe other industries like marine. ACQ is corrosive to metal, especially aluminum. Don't use that for your transom. Now there is a new treated lumber out that is called MCA. It is okay to use with metal. Confused yet??  

Honestly your best bet is to use a marine grade or exterior grade plywood and seal the heck out of it with spar. if you can fit in something with a width of 1-3/4" an LVL beam (laminated veneer lumber) can be had in 14, 16 or 18" widths and would work perfectly for the application. No glue up needed, just cut to fit and rock on. And another plus is that most lumberyards will sell their short length lvl's for dirt cheap. They are typically used for long length beams and are useless as short lengths. 

Got any more questions about lumber, just ask.


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## JustDucky (Aug 8, 2011)

Great response, MoHops. Very informative!


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## delaney (Aug 8, 2011)

Thanks for all the help. I just spoke with a local lumber yard and they said they can order 16" wide, 1-3/4 thick lvl for $20... 

I had another question for MoHops: I still need to coat the beam with marine poly, correct?


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## jigngrub (Aug 8, 2011)

delaney said:


> Thanks for all the help. I just spoke with a local lumber yard and they said they can order 16" wide, 1-3/4 thick lvl for $20...
> 
> I had another question for MoHops: I still need to coat the beam with marine poly, correct?



You really need to check your transom thickness first!!!

All the transoms I've ever seen (but I haven't seen them all) are 1 1/2" thick and 1 3/4" thickness material will not work unless you want to sand it down to 1 1/2".


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## MoHops (Aug 8, 2011)

If your transom can be that thick then yes all you'll need to do is coat the LVL with spar urethance and put it in. Also make sure that your motor brackets will accomodate that thick of a transom as well.


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## delaney (Aug 8, 2011)

Sorry, I guess I should have included that but the transom I tore out was 3 layers of 3/4 inch plywood (yes 2-1/4). So I think it will accommodate 1-3/4.

I am sure it was not sent from the factory like that.


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## MoHops (Aug 8, 2011)

2-1/4" would be a heck of a stout transom especially for a 25 horse. Heck you could even add 1/4 aluminum plate to that LVL and still have room to spare!!


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## delaney (Aug 9, 2011)

Lol, I know. According to the previous owner the boat is rated for 60 hp. It has 3 knee braces on the transom, but things look kind or rough back there right now. I am lucky to have a father who has 30+ years welding and working aluminum, so we will be beefing it back up a little.


Thanks for all the help.


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## jigngrub (Aug 9, 2011)

delaney said:


> Lol, I know. According to the previous owner the boat is rated for 60 hp. It has 3 knee braces on the transom, but things look kind or rough back there right now. I am lucky to have a father who has 30+ years welding and working aluminum, so we will be beefing it back up a little.
> 
> 
> Thanks for all the help.



You should post pics of your work, I'd be interested to see it.


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