Repairing boat trailer

*chris* · Sep 4, 2010

I bought a 17' boat today and the 1989 trailer has seen better days. I will post pictures of the current "repair" which entails some galvanized pipe, some 5/4 pressure treated decking and some lashing! :jester: Holy chit, I had to tow this mess home 80 miles today, but I pumped the bearings full of grease and pumped the tires full of air and it towed like a dream. :blob1:

What has happened is the last 12" -24" of galvanized trailer tube has rusted out. The tube is around 3" x 4". This tube supports a beam across the back that supports the transom of the boat. What I am planning on doing is cutting back to solid metal and piecing in a patch of similar tube. I know a butt weld would not be strong enough, but I am not sure how to best design this joint. Should I weld plates on either side of the joint or top and bottom? I plan on stick welding this with 6011 or 6013 1/8" rod since I have had enough experience to feel comfortable making a road-worthy repair. Plus, failure of this section of the trailer would not lead to a catastrophic failure of the trailer.

Chris

tanglediver · Sep 4, 2010

Air raid sirens wailing, **WARNING, WARNING** Incoming used boat trailer, incoming used boat trailer, prepare for emergency surgery, notify lws, lst, lts, lbs, and all essential personnel, this is not a drill!

*chris* · Sep 5, 2010

Here are some pictures of the "repair" I have been here on and off for a few years, is it taboo to talk about repairing trailers here? I may call the trailer MFG and see if I can buy replacement parts although they are more money than a whole used trailer.

This repair seems very straightforward, what am I missing?

Chris

StickWeldor87 · Sep 5, 2010

Really!?!?

Ed. · Sep 5, 2010

The "structural string" makes a nice touch.

*chris* · Sep 5, 2010

Ed. said:
The "structural string" makes a nice touch.

I actually laughed at the seller when I saw that. Heck, he could have thrown in a few bolts.

So guys, are we just going to make fun of my predicament, or am I going to get any advice?

I am thinking about buying some 3x3 tube in the same gauge and welding a fishplate on either side. Does this seems like the right approach? I will cut the tube at a 45 degree angle to eliminate a vertical seam.

Chris

Rojodiablo · Sep 5, 2010

*chris* said:
I actually laughed at the seller when I saw that. Heck, he could have thrown in a few bolts.

So guys, are we just going to make fun of my predicament, or am I going to get any advice?

I am thinking about buying some 3x3 tube in the same gauge and welding a fishplate on either side. Does this seems like the right approach? I will cut the tube at a 45 degree angle to eliminate a vertical seam.

Chris

The 'string' looks to be spectra. And as the hype should have told all of you- spectra is stronger than steel, remember??? That 'string' is a highly advanced form of a repair designed to work better than the original ever did.

Now, I have 2 words for you regarding the trailer: Start Over.

Just build a new one to those specs. Transfer over the lights, and other parts that are in good shape. If you make the new trailer out of C channel rather than tube, you can clean and paint it, you won't have to galvanize it to get a long service life out of it.

norite · Sep 5, 2010

"but seriously folks"

When you cut back the tube, you will need to cut it back until you hit solid steel. Hopefully you will reach that before you reach the spring mount. If the tube is still rotten there I suggest you replace the entire rail from end to end. The tube may look good on the outside, but if they didn't get galvanizing coverage inside the tube it may be rotten all the way.

Be sure to grind all the galvanizing off at least 1" back from the joint, those fumes are definitely not good to breathe and make it harder to weld. I suggest you use a smoke eater if you have one or at least a fan to blow the fumes away from you. Even if you remove 100% of the galv. on the outside of the tube, the inside will/should be coated. If you can remove some of the inside galv. with a die grinder of even a file, it will be worth it.

A square butt joint would be fine but I also like the idea of the 45 deg.cut you mentioned, in woodworking this is called a scarf joint. You could also weld a 1/4" flat plate to cap the end of the tube, leave the plate about 1/4" proud all around and then weld the replacement tube to the other side, might be easier than trying to do a straight but joint.

I'd like to hear how it turns out.

Stampeder · Sep 5, 2010

I'm with Rojodiablo. Strip all the good stuff off, axle, lights, etc. Get new steel (C channel) and fab new frame. It will take you less time in the end and you will have a much better trailer in the end. By the time you cut and splice that tubing it will take as much and you will still have a patch job. Then painting will also be a hassle.
If you build the new frame you could take it and have it powder coated. A lot of problems will go bye bye.......

Keep the pixs coming.
Glenn.

DesertRider33 · Sep 5, 2010

I agree with at the least, replacing the whole rail front to back. That tube is way too far gone to be good over it's whole length just doing a repair at the tail of it. The other side is probly just as bad inside. Tube is about the worst metal shape one can use on a boat trailer, too much rusting inside the tube.

tanglediver · Sep 5, 2010

Chris, I am laughing with you, not at you.

:laugh:
I have seen one or two crunchy boat trailers in my line of work...

Ed. · Sep 6, 2010

*chris* said:
I actually laughed at the seller when I saw that. Heck, he could have thrown in a few bolts.

So guys, are we just going to make fun of my predicament, or am I going to get any advice?

Chris

Sorry Chris, I couldn't resist before, but seriously now, I would go with what others has said. Ditch the frame, keep the running gear if it is still OK, and build another frame. By the time Galv. RHS has corroded that far, then the rest of it will also be badly weakened by electrolysis even if it doesn't show yet. You don't want to be driving down the highway and hit a pothole, and have the frame crack in half and damaging your boat when it spreads apart all over the highway.

As it's only a 17 ft boat, there is probably about $100-200 of steel in the frame. The time and effort taken to cut out the corroded pieces, prepping the new welds joints, welding and reinforcing them would almost be the same as building a new frame.

Then what you have got is a new steel back end with a potentially risky front end. Is it worth trying to save that small amount of money and time? Build it once and it's good for a great many years. Fix it up and it's only a matter of time before you have to do more work on it or replace it because it broke.

Beside building a a trailer frame in considerably easier and cheaper than trying to repair a boat that departs from a trailer on a highway, I know this because I have done quite a few such repairs on boats in my time as a boat repairer. Just my 2 cents worth.

*chris* · Sep 6, 2010

norite said:
"but seriously folks"

When you cut back the tube, you will need to cut it back until you hit solid steel.

I am going to get the boat up on cinder blocks and get the trailer out of there and see what I am dealing with. I will call the trailer MFG tuesday to see if I can buy replacement tubes. I could fab entire new rails but at that point I may just replace the trailer. I agree with you guys, the tube is probably rusted all the way forward. At a minimum I may repair it to have something to drag the boat around the yard on.

I would fab an entire new trailer but since I will use this in saltwater I really need it to be galvanized.

Chris

Ed. · Sep 6, 2010

*chris* said:
I am going to get the boat up on cinder blocks and get the trailer out of there and see what I am dealing with. I will call the trailer MFG tuesday to see if I can buy replacement tubes. I could fab entire new rails but at that point I may just replace the trailer. I agree with you guys, the tube is probably rusted all the way forward. At a minimum I may repair it to have something to drag the boat around the yard on.

I would fab an entire new trailer but since I will use this in saltwater I really need it to be galvanized.

Chris

Hi Chris, You can just get Galv. RHS or C channel, remove the Galv. just where the joints will be welded by grinding or sanding, and after you finish welding, paint touchup the welded areas with Cold Galv. Epoxy paint, probably good for a decade or so before another paint touch up required. I have done quite a few trailers that way. If you wash off the salt after every boating use you won't have any dramas.

Ed.

*chris* · Sep 6, 2010

Ed. said:
Sorry Chris, I couldn't resist before, but seriously now, I would go with what others has said. Ditch the frame, keep the running gear if it is still OK, and build another frame. By the time Galv. RHS has corroded that far, then the rest of it will also be badly weakened by electrolysis even if it doesn't show yet. You don't want to be driving down the highway and hit a pothole, and have the frame crack in half and damaging your boat when it spreads apart all over the highway.

As it's only a 17 ft boat, there is probably about $100-200 of steel in the frame. The time and effort taken to cut out the corroded pieces, prepping the new welds joints, welding and reinforcing them would almost be the same as building a new frame.

Then what you have got is a new steel back end with a potentially risky front end. Is it worth trying to save that small amount of money and time? Build it once and it's good for a great many years. Fix it up and it's only a matter of time before you have to do more work on it or replace it because it broke.

Beside building a a trailer frame in considerably easier and cheaper than trying to repair a boat that departs from a trailer on a highway, I know this because I have done quite a few such repairs on boats in my time as a boat repairer. Just my 2 cents worth.

Ed, you know I am not too worried since the leaf springs and the axle hold the trailer together from splitting apart.

I do agree completely with you, the last thing I need is a catastrophic failure while towing the boat. I need to get the boat off of the trailer and inspect it as the next step.

You don't think the last 3 feet are shot simply because they are repeatedly dunked in the saltwater? The front half looks ok.

Chris

*chris* · Sep 6, 2010

Ed. said:
Hi Chris, You can just get Galv. RHS or C channel, remove the Galv. just where the joints will be welded by grinding or sanding, and after you finish welding, paint touchup the welded areas with Cold Galv. Epoxy paint, probably good for a decade or so before another paint touch up required. I have done quite a few trailers that way. If you wash off the salt after every boating use you won't have any dramas.

Ed.

I like the idea of ditching the tube and going to c channel. Maybe this is an option as well.

Chris

Rojodiablo · Sep 6, 2010

*chris* said:
I am going to get the boat up on cinder blocks and get the trailer out of there and see what I am dealing with. I will call the trailer MFG tuesday to see if I can buy replacement tubes. I could fab entire new rails but at that point I may just replace the trailer. I agree with you guys, the tube is probably rusted all the way forward. At a minimum I may repair it to have something to drag the boat around the yard on.

I would fab an entire new trailer but since I will use this in saltwater I really need it to be galvanized.

Chris

I will say that your desire for a galv. trailer is good. But repairing that one is a useless endeavor. ANYWHERE you cut and weld..... the inside galvanizing is gone. You can spray galv.... but only the outside. I recommended C channel because you can get a clean, unobstructed paint job on 100% of the metal. Proper primer and topcoat,and you will be good to go for like 15-20 years with good maintenance.

Ed. · Sep 6, 2010

*chris* said:
Ed, you know I am not too worried since the leaf springs and the axle hold the trailer together from splitting apart.

I do agree completely with you, the last thing I need is a catastrophic failure while towing the boat. I need to get the boat off of the trailer and inspect it as the next step.

You don't think the last 3 feet are shot simply because they are repeatedly dunked in the saltwater? The front half looks ok.

Chris

Chris, Yes, that is the reason that it is corroded that badly, but think about what will happen if it fractures just before the springs!!!! When Galv RHS steel or even plain uncoated steel gets that corroded to the point of falling apart, the electrolytic action involved usually has also damaged and severely structurally weakend the rest of it as well. The Galv coating acts as an anode, if the steel is that badly corroded, then the protection has stopped working long ago, at first where it was submerged in salt water and then later up the rest of it.

I have picked up quite a few peices like that to take to the tip and when I put pressure on the bits that still look good, some of them just cracked and bent in half. I can't tell from your pictures about the rest of the frame but from what I can see it doesn't inspire confidence in me. If you look at your first pic you will see that the galvanizing is coming off just before the last spring and it is rusting everywhere in small patches, that is only what you can see from the outside, I would be betting there is a lot more that you can't see on the inside as well.

As I said before, $100-200 buys a lot of peace of mind, boat falling off trailer at highway speed could cost thousand to repair the boat, the motor and the trailer again, not to mention liability cost in case it damages some one elses car or injures someone.

In the grand scheme of things involving boats, $100-200 isn't a huge amount, take away the dollar amount that it will cost to build a new frame and the amount you will have to spend to replace those bits and also time to patch it up and that is the difference you are debating about. You would spend a considerable amount of time and effort to patch up the old trailer with no guarantee it will be safe, building a new frame will take just slightly more effort but it buys piece of mind and gives you a higher resale value if you decide to sell it again later! That to me is better value.

I personnally wouldn't take that chance, not for the relatively small amount of money and effort difference involved.

tanglediver · Sep 6, 2010

I gotta agree on 'C' channel being the smart choice if you replace the entire trailer.

DesertRider33 · Sep 6, 2010

Hot-dip galvanized c-channel would be best for a new frame. You can weld it with fluxcore wire without grinding off the galvi, then cover with cold galvi spray when done. Wear a respirator mask, work outside, keep head out of smoke plume, weld on up wind side of weld, all is well.

Repairing boat trailer

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