Trailer Bunk Replacement which wood?

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Chevy_Mike

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Hello, new here

Last summer I found out that one of my trailer bunks was broken. So I figured I had better replace them before the upcoming season. I have a 2001 Bayliner 215 on a Karavan trailer. I tried to purchase the bunks ready to go, but unfortunately my Bunks are 9 Feet long and apparently nobody will ship bunks that long so I have to build them myself.

Everyone was saying white pine or Cypress wood, unfortunately its hard to find those types of wood locally. I purchased Douglas Fir but the pieces seem almost like they're ready to split, but they all looked like that. I was looking at the Redwood because those pieces looked really solid, but they're really light and I was reading that the issue with Redwood is its too soft and can break. Is the Douglas fir fine, or should I use the Redwood anyway regardless of how soft it is?

Thanks!

-Mike
 

fhhuber

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Fir will work better than redwood. Redwood fractures easily.
Generally people will just go to the lumber yard and buy common 2X4 meant for building houses. This works OK for a few years. They usually have 10 ft and 14 ft lengths.

When you carpet the boards do not cover all 4 sides. Best to just cover the surface that will be in contact with the boat + wrap about 1 inch around the corner and put the staples in the part that won't contact the boat. This leaves the bottom and part of the sides of the board exposed.
Covering the whole board holds moisture in and makes them rot faster.
 

tpenfield

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Yup, lumber yard . . . I bought the PT 2x6 10 footers, but you could always go with non-treated lumber
 

H20Rat

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pressure treated lumber will attack pretty much any metal, something to keep in mind. The fasteners are the first to go, but I've seen brackets deteriorate enough they snapped in 2. Never want PT lumber on a metal boat.
 

mla2ofus

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I've often wondered why Trex lumber can't be used. It bends easily but is hard to break.
Mike
 

jbcurt00

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Ever pick up a piece of faux wood thats been out in the sun for over an hour? Nearly like picking up a wet noodle, esp in 12ft+ pieces.

That stuff only works well supported, ie 16in centers deck framing. IIRC its not rated for 24in spans, but even so....

And when was the last time you walked/stood on just 1 plank, not 2 or more?

A bunk isnt well supported, only 3 or 4 places along an upto 16ft length.

It'd be zero fun to come back to the trailer at the end of a long day boating to find the bunks had drooped between each of the trailer stanchions.
 

Chevy_Mike

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Thanks everyone great advice! I'm thinking I'll stick with the Douglas Fir that I currently already purchased. I'll try to seal it up with thompsons the best I can. I had noticed that they had left part of the wood exposed and wasn't sure if it was because they didn't have enough carpet or what the purpose was. That makes sense though now. To leave the wood partially exposed so it can dry out. I'm hoping next weekend to start on the process! Thanks everyone!
 

bruceb58

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I paint the top and sides with a latex paint before putting the carpet on.
 

Scott Danforth

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I used 4x6 treated fence posts on my current trailer
 

Scott Danforth

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I've often wondered why Trex lumber can't be used. It bends easily but is hard to break.
Mike

Because Trex and other MDPE plastics have the load capacity of the milk jugs its made out of. There is zero strength
 

JASinIL2006

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My '97 trailer was made using PT bunks and stainless steel lag bolts. A couple of years ago, I recarpeted the bunks and the wood was as good as new. The trailer brackets and lag bolts showed no sign of corrosion after 17-18 years. I had thought I might replace the boards when I recarpeted, but the boards were in such good condition that I just reused them.

Obviously, PT wood probably would be a bad choice for an aluminum boat, but otherwise I think it's fine for bunks. It's a lot cheaper than some of the other alternatives.
 

H20Rat

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My '97 trailer was made using PT bunks and stainless steel lag bolts. A couple of years ago, I recarpeted the bunks and the wood was as good as new. The trailer brackets and lag bolts showed no sign of corrosion after 17-18 years. I had thought I might replace the boards when I recarpeted, but the boards were in such good condition that I just reused them.

Obviously, PT wood probably would be a bad choice for an aluminum boat, but otherwise I think it's fine for bunks. It's a lot cheaper than some of the other alternatives.

The PT lumber on your '97 isn't in production, and isn't legal to even buy any more. The copper content in newer PT lumber is up to 90% or higher, it was 10% in yours. Copper + other metal = galvanvanic corrosion.


If you are dying to read more about the fun details of PT lumber...
http://www.finehomebuilding.com/2004/01/01/the-new-pressure-treated-wood
 

boatman37

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mine had PT on it when i bought it. not sure how long it was there but it was still good other than the one piece cracked. i used all stainless hardware to install. i will keep an eye on it though.
 

JASinIL2006

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The PT lumber on your '97 isn't in production, and isn't legal to even buy any more. The copper content in newer PT lumber is up to 90% or higher, it was 10% in yours. Copper + other metal = galvanvanic corrosion.


If you are dying to read more about the fun details of PT lumber...
http://www.finehomebuilding.com/2004...e-treated-wood

I forgot about the CCA vs. ACQ aspect, but I'm sure you're correct. I doubt ACQ-treated wood was available widely - or at all - when my trailer was build.

If one was to use modern PT lumber, wouldn't it be enough to use good quality hot-dipped galvanized (or stainless steel) fasteners? And maybe isolate the wood from direct contact with the trailer brackets?
 

wrvond

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They are so easy to make I don't bother with the potential problems with pt wood. I do, however, use stainless staples to hold the indoor/outdoor carpet on.
 

Chevy_Mike

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Thanks everyone. I spent quite a bit of time looking, I'm thinking I'll just stick with the douglas fir for now since its local and easily attainable, and the PT seems to possibly be more trouble than its worth. I'm going to use Fulton marine carpet, with a marine carpet adhesive, and then stainless steel non corrosive staples to wrap it. Along with some stainless steel lag bolts. The last person to do it used wood metal screws that have been making there way out. Trying to do it semi right this time so it'll hopefully last a few years.

Thanks again!
 
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