A gunter rig offers several advantages for the dinghy cruiser, but there are some snags, especially when the gaff is lowered. If a gunter gaff is lowered for reefing, it is no longer held tight to the mast by the halyard, but sags away at a wider angle. The sail becomes partly scandalised and loses efficiency. In a sliding gunter the gaff is lowered while keeping its vertical alignment. The Otter dinghy gaff stays in close contact with the mast, retaining the proper shape of the Bermudian sail.

There are several ways of achieving a sliding gunter. My approach for the Otter dinghy was to fix to the top of the mast a bracket within which the gaff can slide. The bracket is part open at the rear to allow the mainsail to pass.

The bracket was made, with the aid of a blow-torch, from a strip of stainless steel 1” wide and 1/8” thick. This was bent into a U-shape to make a snug fit over the stainless steel masthead fitting to which the shrouds and forestay are attached. The free ends of the U were then closed in at right angles (while red hot) each side. See the diagram. The U bracket is held in place by a through-bolt in place of the wood screws that originally held the masthead fitting on each side.

The wooden gaff has a square section and is slightly tapered towards the top. The sideways slack between the U bracket and the gaff is taken up each side by a thin packing of anything which will not chafe the varnished gaff. I use a thin piece of plastic each side, wrapped in place by a couple of turns of PVC tape.

As soon as the gaff halyard is loosened and the gaff drops a little, the halyard itself becomes sandwiched between the gaff and the mast, and this must be allowed for according to the diameter of the halyard, probably 6 or 7mm. See the diagram. It is true that the front of the gaff could be hollowed to accommodate the halyard, but this is asking for a jammed gaff, and it is better to keep things simple.

A small Tufnol pulley is tied to the top of the gaff for the mainsail halyard, the down end of which passes through a clamcleat screwed to the heel of the gaff. This is preferably a bridged clamcleat of alloy. The plastic ones quickly lose their grip as the teeth get blunted by chafe on this job.

The gaff halyard is cleated on the side of the wooden mast as usual, but it is convenient to make a fixed loop in the halyard at a point which will fix a safe bottom position for the gaff, so that the latter can be dropped in a hurry without danger of crashing and splitting the jaws. The loop should be of a size that can be passed over the cleat with a squeeze, and left there without its falling off. When the gaff is to be taken down entirely, the loop is brought off the cleat.

All this may sound incomprehensible save to those who have a gunter. For these it will all be self-evident. This sliding gunter on the Otter has all the properties of a conventional Bermudian mast, plus the advantage that in a hard blow the mast can be shortened, saving dead windage. Reefing can be done in a jiffy. For a small reef the gaff can be left where it is at full height. If the weather calls for deeper reefs, the gaff can be lowered to taste. In the extreme, the bottom batten will have to be removed to roll the sail.

A word on a burgee for a gunter. This can take a hammering on a cruising dinghy when the gaff in brought down and tumbled into the boat. I beat this problem by flying my Dinghy Cruising Association burgee on a 15” length of ¼” nylon rod. This bends easily to any angle without harm, and always springs back. It is a push-fit into a short length of stainless steel tubing screwed to the top of the gaff.

MASTHEAD U-bracket for sliding gunter. Not to scale.

In this case non-chafing packing pieces (not shown) take up some of the slack on either side of the gaff.

The lower diagram shows how the gaff halyard intrudes when the gaff is lowered.