Autopilots for trailer sailers

Trailer-sailers are light, mostly tiller steered, and have a rudder that is easy to reach from the cockpit. A tiller pilot pushes directly on the tiller with a linear ram, needs no rudder reference sensor, draws little power and can be lifted off in ten seconds. Nothing about a below-deck system makes sense on a boat you put on a trailer.

Sizing is straightforward: look at the manufacturer's maximum displacement, compare it with your boat loaded for a weekend rather than dry on the trailer, and pick the model that has margin. On a 5 to 6 metre boat the smaller unit is usually plenty. On a 7 to 8 metre trailer-sailer carrying a family, gear and water, go up a size. Confirm the current figures with a dealer, since model limits change between generations.

Tiller pilots want a specific geometry: the ram parallel to the deck, the pushrod at the manufacturer's distance from the rudder stock, and the socket at the height that keeps everything level when the tiller is amidships. Getting that distance wrong changes how many degrees of rudder each centimetre of ram travel produces, which is the most common cause of a pilot that seems weak or twitchy on a small boat.

Most trailer-sailers need a small pad or bracket to carry the cockpit socket, because the side deck is thin. Back the fitting with a plywood or aluminium plate inside the locker. The loads are modest until the day they are not, and a socket that pulls out of the deck in a gust takes a chunk of the boat with it.

On the Gippsland Lakes, Lake Macquarie or the upper reaches of Moreton Bay the pilot's job is easy: flat water, steady breeze, and long straight legs where the value is simply being able to let go of the tiller to make a sandwich or set the kite. Almost any tiller pilot in good order does that well, and a modest response setting keeps the ram quiet.

The South Australian gulfs are a step up, because Gulf St Vincent and Spencer Gulf can build a short steep chop in an afternoon sea breeze that would not trouble a bigger boat but will have a light trailer-sailer yawing. That is where the extra size and thrust of the larger tiller pilots earns its money.

Coastal hops, say Port Stephens to Broughton Island or a run across Moreton Bay and out the Seaway, are beyond what a trailer-sailer should attempt on the pilot alone. Not because the pilot cannot steer, but because a light boat in an ocean swell needs a helmsman's judgement more often than a heavy one does.

Take the ram off before you tow. Road vibration, dust and the pressure wash at the ramp are harder on a tiller pilot than a season of sailing. Unplug it, lift it off the pin, and stow it in a padded bag in the cabin with the pushrod retracted. Blank the deck socket so it does not fill with water and grit.

And be honest about whether you need one. If you sail a 5 metre boat, always with someone else aboard, on day trips inside a bay, the money is better spent on a decent reefing system. A pilot earns its keep when you sail shorthanded, when legs are long enough to be boring, or when you want your hands free to navigate. On a family day sailer it can sit in the locker all season.