View Full Version : Best Wood For Trailer Bunks

10-21-2019, 08:17 PM
I have to replace the old 2" x 6" bunk boards on my boat trailer. The boards removed will no longer hold the lag screws from the bottom, but the tops still look better than what I can buy new from my local lumber yard. I'm guessing that these are the original 30+ year old bunks that Stratos or it's contracted supplier installed -smooth and almost free of any knots.

What lumber is best used for 2" x 6" bunks? My local building supply has yellow pine - both treated and non-treated, but every piece is loaded with knots and voids. The bunks removed are far superior to what I can buy locally. What should I be looking for?

Thanks, Gordon

10-22-2019, 05:45 AM
Best is cypress. Other than that PT pine......

10-22-2019, 09:44 AM
Drill them, use bushings and thru bolt them. You will save a few hundred in wood, carpet and time.


Dave S
10-22-2019, 07:56 PM

home made tunnel
10-28-2019, 07:00 PM
Switch to rollers. The boat will slide on and off the trailer easier. :leaving: LOL

10-28-2019, 07:31 PM
Morning Wood is the hardest wood you can get. Years ago carpet covering was the norm, but now most applications are smooth like teflon.

10-28-2019, 08:14 PM
If you use wood use the yellow pine and seal the crap out of it. I would not use treated.


10-28-2019, 09:09 PM
Guys, thanks for the inputs! I'm going to use new Yellow Pine and will just sort/pick out the best boards I can find in the stack.

I did find this table showing that Yellow Pine is quite strong and well suited - Gordon

No on the rollers. Even if I had 20 rollers underneath, the surface area support is far less than 4 bunks will provide. Here are those wood strength comparisons -


10-28-2019, 09:43 PM
When I was building houses I always tried to use yellow but it used to be hard to find. Only used it for floor joists. Too darn hard for studs.


10-28-2019, 11:58 PM
In all seriousness....

For my transport trailer that has bunks that have lasted for well over 40,000 miles of interstate transports being dunked in saltwater and many different boats, here is what I did to make them stronger. I used West Epoxy with a SLOW hardener and then thinned it out by heating the wood bunk with a heat gun. The heating of the wood to over 100+ degrees causes the epoxy to thin out, thus it goes deeper into the wood grain and makes the wood stronger internally. When you do this, and pre-drill the bunk mounting holes for the stainless lag screws, you will have a longer lasting bunk. This also helps repel water from being absorbed into the wood while being dunked.

You will probably need to invest in a commercial grade stapler, either pneumatic or electric to drive the staples all the way in to secure the carpet.

DO NOT USE BOLTS to secure your bunks to your trailer mounts! So many boat trailers I have seen use this method and when the bunks begin to rot and fail, the gelcoat takes the beating. By using stainless lag bolts you can "monitor" the bunk condition by how easily or rapidly the screws begin to work themselves out. If you begin seeing a lot of them coming out, the wood is getting soft and could go soon.





10-29-2019, 08:38 AM
I ran a layer of ice shield over a set I replaced. No idea how well it lasted it’s long gone

10-29-2019, 10:23 AM
Sure a lot of different ideas on what is best. I have done quite few over the years and the best ones for me were standard non treated pine and I used West Systems on them. I do use galvanized Carriage bolts but seal the holes. This set of bunk came off my V King from around 1995 and they are still good. I have them on a small fishing boat trailer now.

10-29-2019, 08:53 PM
If you use wood use the yellow pine and seal the crap out of it. I would not use treated.


Why not use PT??

10-29-2019, 09:37 PM
Pressure treated wood eats aluminum so if an aluminum trailer or aluminum brackets for the bunks are used it's an issue. Pressure treated wood is usually very wet and trapping that wet under carpet get pretty slimy. If you want to glue your carpet on, good luck. Does not hold screws or staples near as well as kiln dried fir or yellow pine due to it's moisture content. Not real sure what the chemical does to the carpet back. It can be used of course but there could be issues.


10-29-2019, 09:42 PM
Pressure Treated pine cannot be used for rafters or purlings on metal buildings either - they are caustic and will corrode and eat steel so it's a no-go.


Skip 7750
10-30-2019, 08:32 AM
In California, the building department requires galvanized bolts when going thru pressure treated.

10-30-2019, 08:38 AM
Hard to find yellow pine around here so probably going with douglas fir, will seal with epoxy and cover in carpet

10-30-2019, 04:12 PM
Red cedar will last a long time