The Steersman

 The Steersman is a ‘Sheet to Helm’ type Self Steering system designed for yachts between 20ft and 40ft (6m to 12m) LOA.

 Unlike conventional self steering systems, the Steersman does not use a wind vane to sense the wind direction, but instead uses changes in wind pressure in the foresail to sense and control the movement of the helm. Also unlike wind-vane steering systems the whole unit is contained within the cockpit area. This makes it safer to use, it does not block out the stern for other uses, and is not prone to damage from freak waves or manoeuvrings in harbour.

Fitting

 The port and starboard jib sheet winches are unbolted from their positions on the deck and re-mounted on their respective port and starboard Steersman ‘winch platforms’. These assemblies are then either bolted back on to the deck using the now vacant winch mounting holes, or fitted nearby using four bolts per assembly.

The Winch Platforms

 Each winch platform consists of a base mounting plate and pivot, and an upper platform which fits on to the pivot so that it can swing fore and aft.  The jib sheet is cleated off (as normal) to the appropriate winch, and the tension caused by the wind pressure swings the winch platform forward. A spring mechanism made up of a length of shock cord fitted in a block and tackle arrangement counteracts and balances this tension. The tail end of the shock cord is clamped to the winch platform using a jamb cleat and this provides the final adjustment. A simple linking arrangement transfers any tension imbalance to the helm.

Up wind sailing

When sailing up wind if the boat luffs up, the pressure in the sails drops, the jib sheet slackens, and the shock cord spring pulls the winch platform aft causing the helm to steer downwind. Conversely, if the boat veers downwind, then the pressure in the sails increase which also increases the tension in the jib sheet and the winch platform is pulled forward, steering the boat up wind.

Downwind sailing

With the wind on the quarter, the jib is slightly masked by the mainsail. This has the effect of reversing the rules from up wind sailing. Here, if the boat veers downwind, the wind pressure in the jib drops, and if the boat luffs up, then the wind pressure in the jib increases. Consequently the jib sheet must now be fed through a block in the stern end and then led forward to the winch, and the shock cord spring is fitted to the forward side of the winch platform.

There is also transition band somewhere down wind of beam reach when either set up can be used.

Wind Dead Astern

For goose-wing sailing, the system reverts back to normal - jib sheet fed direct to the winch, and the spring fitted to the aft end of the winch platform. However, if the coarse deviates more than about 10 degrees, the forces reverse, and can cause an uncontrolled gybe.

Sail under jib or spinnaker only on this course

Tension Variation

 For different points of sailing, the tension in the jib sheet changes dramatically, from high tension when sailing close hauled, to low tension for broad reach or running. The shock cord spring works with this large variation in the following way. 

The spring consists of a length of shock cord fed through a double block at the stern end (usually attached to the pushpit), and a single block at the forward end which together with the ‘cord-fixed-end’, and the ‘cord-free-end’ are attached to the winch platform with the ‘cord-free-end’ fitted through a jam cleat to adjust the tension. This means that there are 4 shock cords which make up the spring. To reduce the spring tension, the single block and ‘cord fixed-end’ can be moved to a ‘keeper eye’ fitted to a nearby stanchion. This provides a variation in spring size from four cords down to one, whilst still retaining a suitable degree spring movement to operate the helm. For lighter winds, this whole arrangement is abandoned, and a single lighter shock cord is fitted in its place.

Benefits of using The Steersman

·         Easy to install – fits on to the existing jib sheet winch holes or can be bolted down using four bolts.

·         Easy to use. Like riding a bicycle, after a bit of practice, the right settings become automatic.

·         Works in all wind conditions except light airs.

·         Works in all sailing directions relative to the wind.

·         Can be used when motor sailing (on a reach, or close hauled).

·         No ugly framework is attached to the stern of the vessel

·         Eco friendly - it doesn't drain the ships batteries

·         Blends in easily with the cockpit design

·         Ruggedly built; should last a lifetime

Notes

1. In order for the Steersman to operate correctly, the winches must be self tailing, or adapted for self tailing using a ‘Wincher’ (available from most chandlers).

2. Under each winch platform is a locking mechanism so that the winch can be used for normal sailing. Also, with the winch platform locked, and the tiller arm fitted, the helm is locked amidships. This can be very useful as a temporary measure while setting sails, the shock cord spring, etc.

3. We recommend for a course of 165° to180° off the wind – furl the mainsail, and sail under jib or spinnaker alone.