Ideas for trailer bunks

[DaveC426913]

The bolts holding the factory trailer bunks finally rusted through. Now the bunks (2x4s) just fall off willy-nilly.

I'm thinking about how to rebuild the bucks. I'll just use 2x4s again, with carpet stapled on, but how about attaching them to the trailer?

I'd like to avoid screws or bolts sticking up into the wood - in case the wood splits and they end up gouging my hull. Thinking maybe of using strapping and attaching the side of the 2x4s.

Anybody got any good solutions for bunks?

[Tomfoolery]

Use carriage bolts, from the top down. Counterbore the holes so the heads are well below the surface, test fit them, then remove and carpet them with the bolts hanging out the bottom. If the wood splits years down the road, the bolts can drop lower through the holes. But they'd have to really come apart for that to happen, and hopefully you'd have some warning prior to that happening.

[DaveC426913]

Use carriage bolts, from the top down. Counterbore the holes so the heads are well below the surface, test fit them, then remove and carpet them with the bolts hanging out the bottom. If the wood splits years down the road, the bolts can drop lower through the holes. But they'd have to really come apart for that to happen, and hopefully you'd have some warning prior to that happening.

Thanks. Good idea.

But how do you prevent the carriage bolts from slipping when you put the nut on? Will they have sufficient grip? Could I put a toothed washer or lock washer under the head?

[Tomfoolery]

No need. The square under the head will bite well enough to hold, assuming it’s reasonably dense wood and the galvanized bolts aren’t too rough for the nuts to spin on readily. I’ve done a couple of trailers that way, and they’ve always held for the many years I’ve had them. FWIW.

Oh, it helps if you make the holes just tight enough that you have to lightly hammer the bolts through. Makes it easier to staple the carpet since the bolts aren’t moving around, and the wood pinches the bolt and the square under the head once the wood starts compressing. Those bolts don’t do much since the boat loads them against the steel under them, and the shear when doing a Mac Bump (for instance) isn’t much of a load on even small bolts.

[1st Sail]

I used White Oak (NEVER USE RED OAK OR RELATED SPECIES: for the bunks. I presume CCA treated lumber could be used as well.

I used 5/16 stainless steel hex head bolts with washers and nylock nuts. I counter bored the holes the same size as the washers so I could use my ratchet sockets. As the wood weathers over time I can still tighten the bolts as needed. Once fitted I used Sailrite bunk carpet with Sailrite stainless steel staples in the pneumatic staple gun. Worked very well.

[1st Sail]

For the counter bore I used a Forstner drill bit which leaves you with a flat bottom hole.

[hart]

When I built my bunks earlier this year I did it exactly as Tomfoolery describes. His tip on keeping the holes tight is spot on.

The first bunk I made I made my holes a bit too big and the carriage bolts did spin. Wasn’t a big deal, I just wedged them with a screwdriver until the nuts were tight enough. Dropped down a drill bit size for the rest of the bunks and didn’t have a problem.

[Jimmyt]

I used White Oak (NEVER USE RED OAK OR RELATED SPECIES: for the bunks. I presume CCA treated lumber could be used as well.

I used 5/16 stainless steel hex head bolts with washers and nylock nuts. I counter bored the holes the same size as the washers so I could use my ratchet sockets. As the wood weathers over time I can still tighten the bolts as needed. Once fitted I used Sailrite bunk carpet with Sailrite stainless steel staples in the pneumatic staple gun. Worked very well.

Are you sure you're a Mac owner? White oak bunks? Stainless bolts? Stainless staples? Pneumatic staple gun? You are my hero! First class job all the way!

[Banner_IV]

Yea... I went the high tec redneck route new treated bunks with plastic deck boards from the clearance bin at Home Depot screwed down with countersunk 1/4-20 flat head self drilling and tapping wing screws from fastenal. Home Depot now sells similar. Just have to be carefull to strap the boat down as they are slippery.

[Catigale]

I’m going a different route
I over up to 2x6 and will drop 2x6 front and back, building a three sided box around the metal bunk. Two screws will prevent the box from floating away, but the box will not rely on hardware in the metal. I’ll glue and screw the box together with SS screws

Up front of the angle bunk, I routed out 1/8 inch other on my 2x6 and then zip tied them to the steel.

[BOAT]

I have used carriage bolts in the past but there are things you need to do if you use them -

After you install the new carriage bolts and bunks put the boat on the trailer and then RE-TIGHTEN ALL THE CARRIAGE BOLTS! After you put the boat on the trailer all the bolts will be loose again because the wood compresses.

Then, after the boat has sat on the bunks in dry weather for over three or four months you need to do it again because the wood shrinks.

Eventually after many times tightening the bolts one will pull through - that tells you it's time for new bunks. That's the big advantage of them - they usually pull through before the bunk splits.

Screws are a lot easier and need no maintenance but they will rip up the bottom of the boat if a bunk breaks - highlander got messed up bad by those screws once because they poke thought the carpet.

I would be curious about what Cataigale is doing but I do not understand what he said because I am stupid. If he could dumb it down a little it might be something I might try too if I have the tools.

[Tomfoolery]

I would be curious about what Cataigale is doing but I do not understand what he said because I am stupid. If he could dumb it down a little it might be something I might try too if I have the tools.

The cradle for my keel boat had three or four pads on each side, but at the stern it had channel irons with the flanges up and 2-bys screwed into them. Those 2-bys weren't going anywhere. You could add them to the existing bunk supports if you wanted the wood to be captive.

No carpet on those, but it didn't move on the cradle other than the thousand feet from the Travelift runway to the storage lot on the same property.

[Herschel]

I used 5/16 stainless steel hex head bolts with washers and nylock nuts. I counter bored the holes the same size as the washers so I could use my ratchet sockets. As the wood weathers over time I can still tighten the bolts as needed.

Just did this on my trailer restore. I did put two coats of spar varnish on my 2x4's before I carpeted them.

[Tomfoolery]

I copied your bow roller a few years ago when I redid the bunk wood and carpeting. Best thing I ever did to that trailer, or at least tied with replacing the drums with disc brakes.

I had it adjusted a little too high initially, and after the first long-distance trip, the boat had worn a bit of a gouge in the rubber. It's needed to help the bow onto the little front vee-bunks without backing the trailer down the steep ramp to where the ball is in the water, which it does amazingly well, but there's not much reason for it to touch the hull once it's on the vee and all the way into the bow cushion.

[kurz]

A Question to the bow roller on the trailer:

I installed one on the alu factory trailer, did not tested yet. I hope to lounch the boat at the ramp will get easier.

When you trailer long distances do you let the boat sit on that single roll?
I wonder if the axle of the roll can get crooked and if the boat sits better on the original V.

Baybe I overproblematic things...