Trailer overhaul

The old trailer was pulled out to do the centerboard work , so what better time to concurrently overhaul the trailer.

The photo below show the trailer as it was when i got it. The Rear rollers assembly was a rusty conglomeration. It looks ok thanks to cold gal, great stuff for getting road safety certs, But behind the pretty face two guide rollers had seized, the lower one rolled but the whole thing had been welded on a bit too high. The side bunk supports (wooden with white carpet) which hold the bilges up and stop the boat from toppling over sideways, were welded in a fixed position. Besides looking a bit flimsy they were not adjustable and took far too much weight - a possible reason why the boat didn't want to slide off the trailer at the ramp. Another reason was the second rear roller had a bent pin and would rotate only a half turn before seizing.

Next i bought trailer parts - New rear rollers etc. Found out that in Australia blue color ones are for aluminium hulls and are too hard for fibre-glass hulls. So bought red rollers with the medium flexibility rubber -plastic? compound designed for fibre-glass. The trailer had allot of black rollers, these are the softest type but more prone to damage themselves, may be good for wooden boats??

I had only overhauled one other trailer before the Fatty knees 8's box trailer which is a lightweight rig Boat about 50 kg - trailer about 100 kg . The Investigators had to hold up and move a bit more weight about 900 kg of boat and 300? kg of trailer. The Research of  trailers on-line and on the streets revealed lots of good information, the investigator forum again had some good threads and pics to get a better idea. Pics of Investigators on their trailers gave a good impression of where the boat should sit to achieve safe balance etc. I wanted to lower the whole boat by about 4-5" on my trailer - This would make it easier to float off and more stable on the road.

The trailer before work began

At the wyloyard the trailer was pulled out clear of the hull into a nice shady spot. I had planted a sapling deciduous tree long ago and it now grows a very thick crown of leaves in all directions to shade from the western sun most of the hotter months of the year. The shed roof provides good morning shade.

Shade makes all the difference to work outdoors in the tropics

The 5" and 9" angle grinders cutting discs removed the rear roller amalgam but soon discovered the rear box section beam had partially rusted out at its lowest point. So i fabricated a 3 mm plate patch and welded it over the  area.

The trailer was raised onto it's sides for easier work. I chained my 1/2 ton chain-block to the roof beam-support pole join. It's nice to have a strong shed frame capable of lifting heavy objects with chain-blocks, sort of like having your own slow-moving crane around.

The welding is easier down hand and also could access underneath the trailer frame to spots usually missed.

Rust treatment was grinding - chipping the thick stuff off, wire brushing , phosphoric acid to convert rust into black phosphate compound bonded to clean steel, cold galvanizing metal primer spray and then grey water soluble metal primer.

The new rear rollers C-mounts were welded on. Then the keel rollers checked, oiled up to regain adjustment and repaired as needed.

The trailer had way too much down pressure on the tow-ball so i moved the axle 5" forward. Cut away welds attaching the mudguards to the upper frame but left them on the lower axle frame. This allowed it to move once the 6 big u-bolts were released.

Adjustable height side support bunks were needed next. First the wooden bunks were unbolted - most bolts had rusted up. angle grinders cut the fixed supports off the trailer.

Building side bunk adjusters. Bought some 30 x 30 mm galvanized box section tube with 2 mm walls. Recycled the 20 x 20 mm square solid rods fittings which held up the side bunks, de-rusted and painted these - they would later  insert into the adjuster pipes.

To make the adjuster box pipes i cut them to length, the drill press was handy to drill out holes for the locking bolts.

With the 1/2" holes drilled the locking bolts nuts were welded to the box pipe.

Having good welding gear helps allot. Awhile back i bought an automatic shading welding helmet as their price has dropped to affordable levels over the years. These are great as there is no dark glass flap closing by hand when arcing up. They have a small solar panel to power them up from weld rod light too. Another must for me is to use my reading glasses, my usual bifocals just aren't the right tool for this job.  The job quality gets a whole lot better! Good Protective clothing is needed, weld gloves, long sleeves, long pants and slip on steel cap boots. It's hot in summer here, around 30-35 C so have 4 industrial fans  to stay cooler. The most powerful one sits on the ground, has a circular shroud, makes a huge noise and blows like a wind tunnel. It has to be at least 3 m away and not directly aimed at the welding area or it blows the arc gasses about and spoils the weld.

The bunk adjusters were painted , assembled and welded onto the trailer frame. The recycled brace rod was then welded on too. 4 side bunk adjusters were fitted.

Side bunk adjuster - two lock bolts grip the sliding square rod inside. The brace rod adds allot of strength. Axle U-bolt is also shown.

The aft guide rollers  were a 1970's product but looked just right for the job of capturing the keel and guiding it along the center of the trailer. I checked with the marine chanderies in town but nothing like this was available, the choice is wobble rollers only. So restored the originals. First the rusted in axle pins were removed and reconditioned. My slide adjusters were similar to the side bunks except thick wall galvanized round pipe was used. They were welded on to the aft beam.

Trailer rollers reconditioned. The blue side rollers were later found to be too high, so they were lowered to the level of the red keel roller..