Plastic lumber for repair?

[thapharm]

So I have to do some replacing of rotten wood on this old boat I picked up (the seat bases) and I was thinking couldn't I just skip the fiberglass and install plastic lumber and calk it all and re carpet? Wouldn't that be easier than using wood and re fiberglassing it? Let me know what would be the pro's and cons of using solid plastic to replace the rotten boards on this old boat.

Thanks!

 

[JASinIL2006]

That stuff tends to be much heavier than wood and has less strength. Not a great combination for a boat...

 

[Searay45]

Friend of mine used it to replace decking on his Jon boat. Still solid after 8 years in the weather. I wondered about the strength also. Was considering using 2X4 s to replace bunks on my boat.

 

[thapharm]

Yeah I think I am going to use a little bit of it and see how it works. It seems like it would be a good option

 

[Ned L]

It depends on where and how you want to use it. Some places 'great', other places 'just a bad idea'.

 

[thapharm]

What would you consider being a bad idea of use? So do you think using them as planks would be bad?

 

[Ned L]

When you say "planks" I would ask you to be more specific, .... you are talking to a wooden boat guy here and the word plank means something quite specific.

Most of the 'plastic lumber' that is available is not as stiff as wood, and weighs more (as noted above). One of the least desirable places to think about making a substitution would be for stringers. The purpose of stringers is to provide stiffness to the hull. Plastic lumber will not do this.
Other places like floor boards, trim, seat supports it would be just fine (though heavier).

 

[JASinIL2006]

You also need to look at the distance the plastic wood will span. In many uses, you need short spans between structural members because the plastic wood has less strength. Especially when it gets very warm.

Not saying it can't work, but for rot resistance, you're trading away strength and weight. That stuff is also a bit pricy (or it used to be) compared to wood.