My bunks are bunk

the_grube

the_grube

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I bought an aluminum hull/60hp boat on a Karavan trailer new about 4 years ago. No issues with the boat and mo. The trailer on the other hand has failed on me twice. The hardware that the bunks attach to the frame bent and had to be replaced, I upgraded the size and thickness of those brackets.

Last time I was at diamond lake one of the actual bunks failed, the lag bolts pulled out of the laminate bunk and the bunk 'compressed' under the load. (Notice the redneck repair job). I've also noticed that the bunks themselves are bowed in between the 2 attachment points from the weight of the boat I'm guessing. So, my next project is to replace the bunk boards themselves. Not super psyched about the price of replacements I see online and don't want to buy another pair of 'bunk' bunks

My plan is to pickup the straightest pieces of pt lumber (deck grade not ground contact), some angle iron strong back and some sort of plastic sheeting skid material in lieu of carpet. This seems like a reasonable approach but I thought I'd gather up some input from y'all before I go get parts.

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I what I understand is that you shouldn’t use pressure treated lumber for bunks - Something about it staining fiberglass, and reacting with aluminum to cause corrosion. When I replaced mine, I found some nice CVG Doug fir, and it has held up well.
 
 
Thanks all! So I think the reaction between PT lumber and aluminum is only with the old school PT wood? That said, I'm leaning towards Doug Fir 2x4 and the skids that @SurfnFish recommended. I'll probably paint up some 1x1 angle iron and screw it to the bottom side between the mount points on the frame as a strong back and straightener. Still figuring out my options.
 
the_grube said:
Thanks all! So I think the reaction between PT lumber and aluminum is only with the old school PT wood? That said, I'm leaning towards Doug Fir 2x4 and the skids that @SurfnFish recommended. I'll probably paint up some 1x1 angle iron and screw it to the bottom side between the mount points on the frame as a strong back and straightener. Still figuring out my options.
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would recommend 2x6's for increased strength, center the skid plates.
 
SurfnFish said:
Douglas Fir with these on top been on my last two trailer rebuilds, over 15 years on one. Be aware the boat will slide off and on really easy, so keep the bow hook on going down any incline ramps until the stern is in the water
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Are you doing any carpet wrap or just the slicks?
 
SurfnFish said:
Be aware the boat will slide off and on really easy, so keep the bow hook on going down any incline ramps until the stern is in the water
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^^^^^^^^^^^^^^^^^^^^^THIS PART!! ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

If you're used to some stiction because of the old bunks and a sticky non-painted aluminum boat...that will be gone. Ask me how I know! 😁

With my old Valco, I had predictable stiction. I had my routine of clipping a bow line to a cargo hook just inside the truck bed. I would unhook the winch line from the bow even before backing down the ramp so I could just hit the brakes and easy-launch the boat. I had done it for 10 years. I think that's not uncommon for non-painted aluminum boat guys.

As soon as I added SuperSlick to the hull and new carpet to the bunks that routine was not good!
The very first launch after the upgrade I got lucky and the sliding boat (and motor) made it to the water instead of the concrete. That would've sucked. I've seen all the videos of people doing it and it's like nails on a chalkboard.

And now I have a painted aluminum hull so fairly slick.
I still do the bow line to a cargo hook (dockside), but wait until the trailer wheels are in the water before unhooking the winch strap....like I probably should've been doing all along! So maybe this point is moot for you. 😁
 
Evan B said:
Are you doing any carpet wrap or just the slicks?
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just the slicks as the hull has zero contact with the boards. I prep the boards, which I like fresh and as knot free as possible, by round sanding all edges and counter sinking the carriage bolt heads just enough for their top to be below the applied slides.
Then I place the front slide just ahead of the forward hull contact and then space them backwards so the last pad with the 90 degree drop 'tail' lines up even with the back edge of the board.
 
SurfnFish said:
just the slicks as the hull has zero contact with the boards. I prep the boards, which I like fresh and as knot free as possible, by round sanding all edges and counter sinking the carriage bolt heads just enough for their top to be below the applied slides.
Then I place the front slide just ahead of the forward hull contact and then space them backwards so the last pad with the 90 degree drop 'tail' lines up even with the back edge of the board.
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I may give that a go. I need to replace my bunks for my small boat here before fishing starts.
 
My current bunks are really sticky. Actually looking forward to slicker bunks. I don't back-down disconnected. My boat/mo/and payload is heavy enough that I'd be completely screwed if something went pear-shaped on the ramp.

Again, great helpful responses.
 
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Finally got this done. I built the new bunks from doug fir framing material that I found at Home Despot.. not tight grain, but knot free vertical grain and less than 10$ a stick. One of the problems with my trailer is that there are only 2 mounting points on the bunks with 6ft between them. The old 2x4 laminate bunks had virtually no resistance against bending and that caused the lag bolts to pull and gore out the laminate wood which then caused it to water log and turn to mush...
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I stuck with 2x4 and screwed a length of 1in EMT to the underside to bolster it further against bending. These things support my weight (~200lbs) without hardly budging.
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And here's the final product. The boat slid up onto trailer nice and easy, the way it should. Really happy with the results
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Guy Gregory said:
EMT: cool idea! I may retrofit mine which I renewed last year
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I was going to use some aluminum angle... then I saw the price of aluminum and all bar stock; yikes!!

I cut a small dado right down the center of the board to keep the EMT from rolling while I drilled and screwed it down.
 
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