Trailering 2

These brief notes have been written after our experiences over several years and after personally launching Wizard, Sango and Savannah 26.

General procedure for launching and recovery:
An extra draw bar between car and trailer ball hitch will help (alternatively a rope can be used but it makes it harder to control the trailer). You will need about 1.2m depth water at the back of trailer for launching (ie similar to most monohulls). If the slipway slope is too shallow then car may end up in the water unless a draw bar is used. If it is too deep then it can be difficult to retrieve the boat, or prevent the car from sliding when launching. (Leaving the car at the top of the slip and using a long rope usually works). Remove mast engine etc. Generally make boat as light as possible by removing loose gear. Untie boat, lower chocks and ensure that hulls are free to swing out. Close hull hatches. Back trailer into water.

On an ideal slip the boat will simply float off the trailer unfolding as it does so with no effort required from the driver. The bouyancy of the hulls lifts them as the trailer is reversed. Once off the trailer the boat can be motored away or brought back to the shore for stepping the mast. Note: the beam straps are not essential for motoring or even sailing in calm water (again the buoyancy of the hulls holds the boat together).

When retrieving on an ideal slip the reverse applies. Motor the boat in onto the trailer. It is important that it fits square on the trailer and that the chocks line up. The front chocks should be tight against the front trailer support, then the back chocks will line up automatically. Obviously they will be under water so will be hard to see, it is worth having some flexible poles to act as guides on the back of the trailer. (Similarly, as the boat will be wider than the towing vehicle fit ‘‘cats whiskers’’ to each side of the front of the car to make the car the same effective width as the trailer).
If it is not an ideal slipway then the trailer will need to be hinged to lower the effective boat height. To launch, back the trailer in as far as you can, the trailer wheels should certainly be well covered. Then slowly start unwinching the supports (the boat may need a good push to get it to start). As the trailer is lowered the hulls make contact with the water, bouyancy comes into play as before and the boat begins to open. Once floating clear the boat can be motored away. Retrieval is a bit harder as the aft chock has to be positioned correctly. If you are trailering regularly then make some clips to hold the support in place, otherwise lashings will work. It seems best to bring the boat into the slip and position the trailer under the boat. Then lift up the supports and lock then in place. Floating ropes on the aft support will help. Then push the trailer back out into deeper water and winch up having first undone the beam clamps. The further the boat is in the water the lower the winching loads.

The aft diagonal brace should slide along the aft support as it rises/falls, providing the diagonal brace hinge does not allow sideways movement. Otherwise fit some cheeks to the brace.

General Comments (in no particular order)

The PBO boat test showed Wizard being assembled on a slipway at low water but we've found that it is very much easier to assemble the trailer partially in the water.

Unlike the Farrier designs, for example, the trailer design used on Wizard and Sango allows the boat to be readily removed from the trailer when on land without the use of a crane. It also enables the boat to be got onto the trailer in the first place.

The trailer drawings should be considered more as close approximations rather than detailed working drawings. This is partly because every boat will inevitably be slightly different, but also because trailer manufacturers use slightly different components.

The most load on the winching system will occur when the arms are at their lowest position and the boat is about to be raised. The turning blocks to the winch are under very high load (1T+) and must therefore be strong enough to withstand such loads. To reduce the loads either launch into the water (see above) or lower onto trollies or blocks that ensure that the keel is at least 400mm above the ground.

Don’t ever have the boat sitting on the raised trailer with the hulls in the open position. They should always be allowed to fold down under the cuddy. Otherwise the centre of gravity would be too high and the boat become unstable.

Avoid launching/retrieval with a current across the slipway or with on-shore winds.