Narrowing a trailer frame

[Stumpalump]

I needed a narrow trailer for a long skinny Grumman Sportboat. The frame I had was just way to wide so the easiest thing to do was grind off the mounts on the axle frame and relocate them in. The frame did not bend easy. It took three ratchet straps for safty and I had to pull the rails until they touched to get them to bend. It was formed and bent at the factory so I thought it would bend easy especialy since its only a 1600 pound trailer. After three attemps it still springs back but it was close enough to work with. The stored energy when doing this would break both legs or kill you if it got away from you but it worked. I did not want to heat it because its galvanized so I smacked on the bending locations with a heavy hammer to relive the metal. I should have bunks on it in the morning. Here you can see the old location vs new.

 

[Stumpalump]

Here is the boat and trailer problem.

 

[NYBo]

Looks good, but you have created weak spots where you created the bends, But with a boat that light, it probably will never be an issue.

 

[Stumpalump]

Looks good, but you have created weak spots where you created the bends, But with a boat that light, it probably will never be an issue.

This was one of the trailers that is factory bent like muffler pipe. I spit the bends to the two spots the factory used. I relived the bend near the tongue. See how its already factory dimpled? The second bend was in front of the bunks. I suported it with a bock and just added a little bend to it. The frame mounting perches got relocated 9”. The little tabs that the bunks screw to got fliped inward so I would not have to bend so much. I heated them and bent them to 10 degrees to match the hull. I got the bunks installed and worked on the next major problem. These boats are little more than a huge freighter canoe except made for an outboard or oars. It has no drain plug. Due to the condition and rarity of these cool old Grumman Sportboats I did not want to drill one. Its 110 pounds. I can flip it. Problem was flipping it on the trailer while solo had it falling and jamming between the bunks. I fooled with blocks of wood and bunk mods for an hour. The solution was to put stiff steel sheet in the midde. The boat rolls right over now. I used eight 1/4” pop rivits and carpeted the center.
Different enough project to add here and want to warn again about the immense stored energy involved. I used a wratchet strap with two additional straps so that I could walk the energy in and out without breaking both legs. Zink spray paint simulates galvanized metal to cover the welds and work done. The galvanizing needs to be ground off clean so the welds will stick. Redwood is available here for bunks because presssure treated wood and aluminum corrode.

 

[NYBo]

I have a friend who has one of these boats. I believe he bought it new. It makes a great fishing platform.

 

[jimmbo]

Me thinks you will need to relocate the axle further back to put enough weight on the hitch. Tongue looks a little bent too

 

[Stumpalump]

Me thinks you will need to relocate the axle further back to put enough weight on the hitch. Tongue looks a little bent too

Good eye. Yes the reciever is tweeked by an aparent light jack knife. I cleaned, lubed and adjusted it and it checks out better than it looks. The axel location can be slid by just loosening the U bolts. I put it where I found it but probably need to remove the lower leaf to soften things up first. I’m definatly not 100% delighted with it and may build side guides and move the axle. Its kinda an optical illusion that the axel is so forward with the skinny rails. There is no weight to any of it except the trailer. The tongue weight felt heavy in that location 75 poundish and why I did not move it. I’ll throw a scale under it when I get back in town.