UK-Cherub Class

Get Your Heart Racing


Building a Trailer

Boat trailers are not cheap and it is all too easy to forget about the cost of one when costing up a boat build. However, with the right skills and tools you can save a large sum of money over the cost of buying a new trailer by doing things yourself. This page shows the re-build of an old trailer that once belonged to Flat Stanley. Although, so little of the old trailer was servicable that this should give enough information for a new trailer build.

Disclaimer

The methods we used to repair the trailer are outlined below, they may or may not work for you, involve the use of dangerous equipment and failure while driving is very serious, if you intend copying any of the techniques used please ensure that you understand all the risks involved.

Salvage what you can!

When we started, this old trailer was barely a trailer at all. The tow hitch was solid, as was the main beam which runs along the trailer length as well as the the mast crutch and bow support. The wheel bearings were shot and the rear crossmember and suspension was corroded so badly that it took on the appearance and structural propeties of puff pastry when hit with a hammer. So out came the grinder and we got to work.

The bits we saved were:

  • The main beam (this runs the length of the trailer and has other parts attached).
    • Tow Hitch
    • Mast Crutch
    • Bow Support
    • Front Cradle
  • The flat tie beams (these triangulate the join and keep the trailer square).
  • Mud guard brackets.
  • Wheels.
  • U-Bolts (some of these got destroyed by the grinder and were replaced).

Tow hitch on main beam:

trailer1.jpg

Get Supplys

The bits we need to make a functioning trailer were:

  • Bearing/Suspension units (the light duty ones we found were rated at 350Kg, a little heavy duty for a Cherub trailer but will do the job).
  • Rear cross member (we purchased one ready made which is fine for us as we did not want a combi style trailer but if you want yours to be combi style you will need to make one as the pre-made ones for the light weight wheel hubs/suspensions only come in a narrow format. Fine for just a boat but too narrow for a boat and trolley).
  • Mud guards.
  • Assorted nuts and bolts.

These can all be sourced from Towsure.

Head for the Shed

Once you have your parts you will need to get hold of a welder. We used an arc welder as it is easy to use and does not require gas bottles. You will probably need something like 100A current for this kind of work. If you are new to welding then get some practice first with some scrap metal. Weld a tab onto the center of your cross member, this is what your u-bolts will clamp on to so it has to be substantial. We also welded the flats of the u-bolts onto this for good measure. You will then need to weld some rings onto your crossmember for strapping the boat down. Again, these need to be strong for obvious reasons!

This shows the flange and the u-bolt flats all welded up:

trailer2.jpg

This shows the rings for strapping the boat down:

trailer3.jpg

That is all the welding done. Unless you need to make mud guard brackets. The next thing to do is to bolt your cross member to your main beam with two u-bolts. Then add your flat tie beams (traiangulation struts). These are fixed with a single u-bolt and the front end and the rear end is fixed when the suspension units are bolted on. Then either make, buy or salvage some mud guard brackets and bolt the whole lot together with your suspension units and cross member. Bolt your mud guards on and the jobs a good-un!

Cross member attached to main beam with two u-bolts:

trailer4.jpg

Front of flat tie beams attached to main beam with u-bolt:

trailer5.jpg

Rear cross member showing suspension unit, mud guard bracket, flat tie beam attachment and tie down ring:

trailer6.jpg

Put the wheels on and you have a trailer. Now all that is left to do is to add a cradle or trolley supports and give it a coat of paint. Red-oxide primer and Hammerite should do the trick.

trailer7.jpg

trailer8.jpg

Schoolboy error!

After finishing the trailer it came to my attention that I had forgotten post 97' boats have a 30cm 'snout'. This meant that the bow support had to be moved to allow for the snout to sit behind the mast crutch. The old bow support was simply cut off and welded on to a bit of 50mm box 300mm further back. The whole assembly sits just shy of 200mm above the main beam.

trailer9.jpg

Cradle

There are as many ways of doing this as there are Cherubs but I thought I would add a little note as to how I did it for reference. The cradle is made of several layers of 4mm exterior ply laminated together with support at each end and a large weight in the middle. This is then secured to the supports with four coach bolts. Coach bolts are used as they have a shallow, round head which wount stick through the trailer padding. You could use counter-sunk bolts for the same reasons, which may be neater.

trailer10.jpg


tech/trailer.txt · Last modified: 2013/06/25 15:55 (external edit)