Gunter rig

In sailing, a gunter is used for two main configurations of rig:

A sail raised by either of these means is called a gunter rigged sail. A vessel with a gunter rigged mainsail is called a gunter rig.

Gunter rig is normally used on small gaff rigged sailing vessels, such as sailing canoes (not the International Canoe) and dinghies where the gaff is carried very nearly vertical, forming an extension to the mast so that the sail is triangular, resembling a Bermuda rig. The effect is to have a topmast (the gaff) which is a pseudo telescopic extension of the shorter mast. One reason given for the popularity of the gunter rig in dinghies is that the mast and yard are sufficiently short to pack neatly inside the hull when a boat is being trailed behind a car.

In what follows, broadly speaking, the 'single halyard' sail is known as a "sliding gunter," while the 'double halyard' sail is a "folding gunter." The sliding gunter yard stays essentially vertical while being raised, while the folding gunter is 'hinged' up to the mast from the horizontal, much like a high-peaked gaff sail.

It should also be noted that while the term yard is normally employed to name a spar which crosses a mast, and gaff one which is fastened to the mast at its forward point — as it is in the case of the gunter rig. However, since the gunter rig is derived from lug rigs - where the spar from which the sail hangs is always called the yard, rather than from gaff rig - despite the similarity between a high peaked gaff rig and a gunter rig, the spar will often be referred to either as a gaff or a yard.

Even with a single halyard the hooped gunter is a vertical sliding gaff

One halyard, the peak halyard, has a block, sometimes just a shackle, that allows the gunter (wire parallel to the gaff and fixed to it at two points on its upper (or leading) surface) to raise the gaff into the vertical position up against and parallel to the mast. The other, the throat halyard, is used to raise or lower the jaws of the gaff.

...
Wikipedia