Pontoon trailer bunks…

[Jeff J]

They are constantly working loose and falling off. As near as I can tell, the trailer flexing is ripping the lag bolts out. Does anyone know a better way to secure the bunks than the lag bolts through the bottom that the manufacturers use?

Options are pretty limited since nothing can protrude on top. I thought about bolts and recessing the heads but don’t know if it would be a good fix. It could cause issues with the carpet and accelerate rot. Moving bunks around to line up good wood with mount holes is getting old but may be something we just have to live with.

Maybe a better bunk material is needed. Bunks appear to be yellow pine but I am not a wood expert.

 

[airshot]

I used carriage bolts ( the rounded heads) with a pair of jam nuts on the back side. Once covered in carpet, no worry about scratches, and jam nuts are on the back side. Do not cover the back side of bunk with carpet, as this will help the bunk board dry out better and add some to the life expectancy.

 

[flashback]

I use carriage bolts too, and recess the heads about a 1/4 inch, no carpet, boat slides fine on the bare wood.

 

[dingbat]

Stainless steel or hot dipped Fanged elevator bolts with nyloc nuts would work well in this application

5/16"-18 x 2-1/2" (USS) Fanged Head Elevator Bolt - 25 Pack - Kimball Midwest

 

[jlh3rd]

They are constantly working loose and falling off. As near as I can tell, the trailer flexing is ripping the lag bolts out. Does anyone know a better way to secure the bunks than the lag bolts through the bottom that the manufacturers use?

Options are pretty limited since nothing can protrude on top. I thought about bolts and recessing the heads but don’t know if it would be a good fix. It could cause issues with the carpet and accelerate rot. Moving bunks around to line up good wood with mount holes is getting old but may be something we just have to live with.

Maybe a better bunk material is needed. Bunks appear to be yellow pine but I am not a wood expert.

I have a 24' that I re-did the bunks on.
The original problem with my lags were that they rusted to the point they wouldn't hold. I believe they were galvanized but I'm talking 2006.
I found stainless steel ones, 1/1/4". And the threads are cut sharper. I used yellow pine and also left the undersides uncovered. It's been about 3 years.

But..gotta say, .I like dingbat's idea. that'd be super easy to recess and nylok nuts....problem solved.

 

[Jeff J]

Thanks, I received a call this morning that they were bringing me a boat but needed me to come fix the trailer first. One bunk had fallen completely off and I found 3 other bunks loose. They all give me trouble but this trailer only has 2 bolts per bunk (one front and 1 back) so they don’t hold long. The mounts are also in line with structure so no rattle gun access which makes lag bolts something less than convenient. Some are even blocked by fenders making it impossible to replace a bolt.

This particular trailer should be pretty easy. It came with the plastic slides covering the bunks. They have three more with carpet.

I have found corroded out bolts on some bunks. I learned a few years ago galvanized isn’t good for anything that gets wet. I think they rust faster than cad plated steel. I am going to see if I can talk the powers that be into some trailer maintenance this winter (the boats will be stored on the dock).