Volvo Ocean Race

Galley
Kitchen on board

Gennaker
A cross between a spinnaker and genoa, used for broad reaching.

GMT
Greenwich Mean (or Meridian) Time is the average time that the earth takes to rotate from noon-to-noon. The Greenwich Meridian (Prime Meridian or Longitude Zero degrees) marks the starting point of every time zone in the world.

GPS

Global Positioning System. Satellite navigation system that fixes a position on the earth's surface by comparing the minute time differences between signals transmitted from a selection of satellites and a controlling ground station. For the Volvo Ocean Race, navigators have to carry sextants and know how to use them in order to use conventional sun or star sight navigation if there is a catastrophic breakdown of GPS either on the boat or in the system itself.

Grinder

Crew member who is using the pedestal system in the cockpit to apply force to the winches. Also the winch system itself that is operated by the pedestal system - the grinder pedestal.

Gust
Sudden increase in wind velocity

Guy
Also the line used to control the outboard end of the spinnaker pole, running from the sail. Certain nations, particularly Australians and New Zealanders, call the guy a brace, which is in fact more likely to be correct, coming as it does from square rig terminology where the braces were used to turn the yard arms of a ship so that the wind caught the sails in the correct way.

Gybe
To change direction by turning so that the stern of the boat passes through the wind. This means that the sails, particularly the mainsail, can swing across with great force; gybing has to be approached with care

Halyard
Rope used to hoist a sail

Halyard lock

If a halyard is used to hold a sail up a mast as well as hoist it, which is the usual situation, the rope from which it is made has to carry an immense load all the time, not just the weight of the sail down the aft side of the mast, but also the tension applied to the halyard down the other - twice the load in fact. This compression load has to be carried by the mast, making it heavier than it need be. Cut the compression load, cut the mast weight. The way to do this is to lock the halyard at the top of the mast. Halyard locks are usually special top slides attached to the sail, which run up the track on the aft side of the mast and which have a pin or two which engage in the track to lock things off.

Harness
A webbing harness worn about the torso, generally over any clothing, with a detachable tether made from nylon with attachment hooks. Intended to prevent a crew member falling overboard and becoming detached from the boat.

Head

Top corner of a sail. Also the term for a boat's toilet.

Headsail
One of the triangular sails set forward of the mast. Interchangeable with jib.

Headfoil
An extruded profile, usually in plastic, which is fitted over the forestay and is specially shaped to take the luff of a headsail. The smooth leading edge thus ensuring aerodynamic efficiency. The headfoil usually has two grooves to allow headsails to be changed by hoisting one over the next and then pulling the first down. This avoids a bare headed change.

Heave to
To stop the boat by easing the main sheet and backing the jib and, depending on the way the boat behaves, probably putting the rudder fully over too.

Heel
A boat heels when it leans over due to the sideways force of the wind.

Helm
Not the person who steers the boat, that is the helmsman or helmswoman, but the device with which they steer, either a tiller or a wheel.

Helmsman
The person steering the boat.

Instruments

Sailing instruments aboard a Volvo Open 70 which give a vast amount of information such as true and apparent wind speed and direction, VMG (velocity made good), CMG (course made good), boat speed, depth, water temperature, repeats from the GPS navigation system all shown on various displays. On the mast, large sized displays are easy to see from anywhere in the cockpit; close to the helmsman and down at the navigator's desk, smaller displays are available. All can be switched to display a wide range of information.

Inversion
A capsize where the boat goes completely upside down (turns turtle).

Isobar
Lines on a weather map that join together points of equal barometric pressure. The resultant concentric figures are known as low pressure systems or depressions if the pressure decreases as you go towards the centre, as anticyclones or high pressure systems if the pressure increases towards the centre.