Dual axle aluminum trailer

tkanzler · Oct 7, 2013

Extending the main rails isn't going to be easy, and wouldn't be worth the trouble, IMO. You'd also have to move the axles back, but they're likely bolted, so that should be the easiest part.

The donut is a lunette ring for connection to a pintle hook on the truck. Common for larger trailers, like big tag-along flatbed trailers for hauling heavy equipment, dirt trailers, etc. Even the dolly trailers used for connecting a second trailer in a tractor-tandem/triple trailer setup use lunette rings. Sloppy and tough, but effective. You can even get surge brake couplers with lunette rings.

tkanzler · Oct 7, 2013

Aluminium is different to weld than steel, but there is no shortage of weld shops that can do it. If all you need to do is reconfigure the bunks, I wouldn't think it would be much of a project (said without seeing the trailer, of course), and any trailer shop should be able to handle it.

dscribner · Oct 7, 2013

You want to be careful welding aluminum. Unlike steel, aluminum weakens at the weld. That said, I had four "stantions" welded up from 4X4X1/4 6063-T6 aluminum tube. There is a saddle on the bottom that sits on the 3X3 steel tube trailer frame. You'll see it sitting next to the steel one that I first had on the trailer. I used the original roller assemblies from the trailer and bolted them on. I also built a steel roller bed to put under the keel. Waste of time really because the boat is tipped up and off that part until we pull out. So, a few more bolts to capture the frame and I was mobile again. Note that I have a bolt on gusset. I also have angles inside the tube, thru-bolted to the saddle. Just in case the weld weakens. Belt AND suspenders.

Ray Bowles · Oct 8, 2013

A good welder can weld aluminum without loss of strength. I've built a lot of equipment out of aluminum without any problems. That said, I would find a trailer manufacture or a high volume boat dealer about buying roller or bunk rail adapters. These bolt to either your cross rails or main rails and allow the mounting of multipule rollers or bunk supports. These are pre-made and adjust to fit any boat hull. If all this is too much of a hassle then consider selling your trailer and buying a standard boat trailer.
Ray

dscribner · Oct 8, 2013

We employ certified, professional welders. I am an architectural designer. Aluminum looses as much as 40% of its strength within 1 inch of the heat effected zone (depending on who's doing the calculations and what he's trying to allow). Anyone telling you otherwise is unaware or selling something. The loss can be overcome by augmenting the weldment at key locations, hence my angles. Or it may be over built. Next time you walk into the airport, the mall, government building, go to the national zoo or Arlington National Cemetary, look up. You'll see my work. (Or something like it)

Spence · Nov 18, 2013

Picflight said:
How easy or difficult is it to modify a dual axle aluminum trailer for a 17' power boat? Is this something that trailer manufacturers or service centers do on regular basis? I'm not sure if welding an aluminum trailer is a specialized task.

I came across someone selling an aluminum trailer with no bunks that was used by the navy seals for their rib boats, it has some sort of doughnut hitch connector.

Aluminum Trailer!? Now there's a hostile alliance.
I would never buy an aluminum trailer. The small gains you would obtain in poundage does not justify the gains in torque,toughness and ability to handle the sheer stresses that steel provides.

That's like the plastic replacement phenomenon we see more often these days. Products that now guarantee 1/3 the life of the original. That reminds me, gotta replace the broken plastic handle on my snow shovel before winter.

Dual axle aluminum trailer

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