Trailer fenders questions

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Active member
May 3, 2024
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Tyler, TX
I recently have been fixing up a Jon boat I bought used. I noticed today the fenders on the trailer have no backing plate. So there is an opening between the tires and the boat. Do you see that as an issue? I might could fashion something, but I'm not sure if it's needed?

Also, there is not a lot of room between the boat and the fenders. I'm worried I could be going metal to metal while loading if I don't do it just right. I was thinking of gluing bunk carpet to the inside edge of the fender but I'm not sure.

Here's a pic.


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I wouldn't use bunk carpet as that will close the gap between the trailer and the boat. Any rubbing while transporting the boat will cause abrasion to the hull. It looks like you have an inch or so between the fender and boat which should be good. However, you could maybe install a shim, such as washers, to move the finder towards the tire.
A backing plate would be nice to keep gravel from being tossed against the boat continually while on such roads. Make a couple if you can and install them.
You can carpet the backing plates.
Raising the bunks will increase the space between the boat and the fenders. Going one inch up might give the space you want.
My 1436 has fenders like that. Actually yours are better mine are literally a piece of plastic 55gallon drum that was cut out and used as fenders. It's never been a problem but I don't put many miles on that trailer.
I have a boat which obviously has had the tire come up and hit a mounting bolt under the fender. You can see a slight groove in the tire in the same spot. What I did was drill new holes an inch higher and remounted the fenders. Don't think I'd worry too much about them being open on the boat side. Worse case scenario if you get stuck in a rainstorm some dirt will get tossed up onto the boat, but it was going to need a good cleaning anyway, right?

Another guy recently put oversized tires on his and I mentioned at the time that you need a good bit of space for hitting bumps. On my rig I think 3" would be about the least I'd be comfortable with. That axle WILL jump up quite a bit on you if you have to go down a rough road or hit a big hole by accident.
I may be saying the same thing as @Stand Up . If you want more room it looks like you could move the fender outwards to center them over the tires. That is assuming they can be moved without too much trouble. Then make sure your bunks are adjusted property so your boat sits correctly between the fenders. Adjust the side bunks, and Bob's your uncle!

My fenders are also open on the inside. I didn't realize it was an issue.
The clearance of boat to fender in that pic doesn't worry me much since the boat has side bunks and should be secured at the bow.
It does look like the tires can contact the fenders during suspension compression. I'd want as much distance between the tire and inside of the fender as there is between the axle tube and frame plus about 1/4" or so. That way if the springs bounce full range the tire can't hit the fender and bend it upward into the boat or worse yet catch the tread and get ripped off. Depending on how they're mounted, (I've seen some painted trailers with welded fenders, some with clamps, some with through bolts in the frame), I'd space them outward to center them over the tire better. Making up a shim or spacer is fairly easy, for mine I just took a length of U channel and bolted one side to the frame and the other to the fender, which moved my fenders outward about 2" on the trailer that holds my 14ft boat. Mine does not have side bunks but does have guide posts at the rear.
From what I have seen, many manufacturers use carpeted plywood for that opening, so if you do hit it while loading, it won't damage the boat, and if you're running down any wet gravel roads it'll help keep the tire from slinging grit onto the boat.
I'd go with that, take a piece of wood, counter sink a few carriage bolts through it, cover it in carpet an bolt it at an angle to the inside edge of both fenders, it'll act both as a pad and guide to hold the boat in place both on the road and while loading.

If not leave it alone, its not that close and if the boat fits the bunks and bow stop correctly just tie it down and go. I spent half a day lowering my boat between the fenders like that just so I don't have to sink it so deep in the saltwater to launch. Of course I'm not at all worried about scratching my 50 year old boat either.

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