In an effort to reduce costs, Martin Parker built a float-on-float-off trailer.
When buying my first cruiser, Muddy Waters, a 26ft Colvic Sailer, my under¬standing with my wife was that the running costs would be low - well, almost. In practical terms, this meant a cheap drying mooring and a launching trailer on which to transport the boat, where I could work on it without incurring launch¬ing and storage costs. In my inno¬cence, I thought I could just buy any old boat trailer to do the job - but soon realised that what I wanted wasn't available, and if I had one made specially it wasn't going to be cheap.

Going it alone
After visiting the local boat yard to look at other trailers, I thought I could build one myself. Provided I could divide the project into man¬ageable chunks, and concentrate on them one at a time, I didn't think it would be too diffIcult - though it was certainly going to be time con¬suming.
But this I jotted down what I hoped to achieve:

• . It must be possible to float the boat on and off, with no risk of damage.
  . The trailer must be towable by road, at least for short distances. . Reversing should be as easy as possible - which meant rear wheel steerability.
  . It should be possible to take the trailer apart so it can be moved any distance by road on another trailer. . It shouldn't take up too much room when stored - drawbar and goal posts must be easily removable.
  . It must provide good access to the underside of hull for antifouling and maintenance.

The second job was to establish the various dimensions as accurate¬ly as possible. Some of the data was scaled off from the original plans, but - as these were crucial - the keel dimensions were obtained by drying out the boat and measuring them directly.
Keel location design
My biggest problem was how to make the encapsulated glassfIbre keels locate on the trailer exactly where I wanted, without them becoming chipped or cracked when the boat was floated on.
After many sketches, I decided to drop the keels into the top of a pair of 'H' section steel beams, which would mean positioning them to within an inch after floating the boat on. Impossible, you say? Not at all. How I went about it can be seen in the photographs. A 4inx2in wooden nudge bar stopped the keels over-nmning their position and two sloping timber panels guided them down into the bottom of the 'H' sections. All of the guides were fastened with stainless steel screws so they could be easily removed to gain access to the underside of the hull.
Supporting the weight
With a four-wheel trailer, the steel beams between the back and front wheels have to be strong enough to support the whole weight of the boat. The 'H' sections weren't strong enough for that, so addition¬al 'T' sections had to be welded underneath to beef them up.
The rest of the trailer was then built around these steel beams. The two off-cuts from the long 'H' sec¬tions were used for cross members, connecting the two sides of the trailer. It would have been easier to attach them by welding - instead I used M12 bolts so I could break the trailer down for transporting long distances on the road.