If you use Firefox – For nautical terms, select the word and then right-click. Click on Search Google for “*” – the word which you selected. You will usually get specialised sailing sites or Wikipedia.
I have always found the gaff rig aesthetically appealing, being the most characteristic feature of a fine classic yacht. It uses a four-cornered sail, giving a fourth point for setting the sail to the wind. This old rig carries more sail than in the modern bermudian or the gunter rig I have on my own boat.
The gunter rig, like the bermudian rig, sets the sail by three points but uses a gaff-like spar called the sliding gunter. The gunter on a Mirror dinghy is made more like a gaff than the traditional gunter. Its only advantage for me, other than aesthetic, is that the mast and the gaff are no longer than the hull for transport. Very practical for the motorway pay booths. The sailing performance is similar to the bermudian rig, but perhaps not quite as good windwards.
In a true gaff rig, with the four-cornered mainsail, the gaff is controlled by two halyards (I only have one on my gunter-rigged boat). One halyard tensions the luff and takes the main weight of the sail, gaff and boom. The second halyard fulfils the role of the downhaul: it tightens the leech of the sail for sailing upwind. Like the downhaul, a gaff vang can have multiple pulleys to make the hauling easier for the crew.
The jib or jibs on a gaff rigged boat run from the mast to the bow of the boat and the end of the bowsprit. On a true gaff-rigged vessel, a topsail can be positioned between the gaff and the mast for extra sail in light wind. A gunter rig does not have a topsail.
The advantage of a short mast are obvious for transport. Also, for sailing under bridges, a bermudian rig has to have the whole mast and standing rigging removed. A gaffer or gunter rigged boat can merely take down the mainsail and go under the bridge by engine or oars, or under jib alone if running before the wind or in a broad reach.
Gaff rigs give vessels a tremendous amount of weather helm, and this is compensated by adding a second of third jib and a bowsprit – the cutter rig. The rake is more easily adjusted with a gaff, and this helps to balance the boat for the helmsman. A gaff rigged boat can more easily broach when running because of the amount of sail overboard.
There is often confusion between the gaff and gunter rigs, but terms are easily interchangable as for the running rigging items like the cunningham, outhaul and downhaul (boom vang).