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## What is J measurement?

The joule (/dʒaʊl, dʒuːl/ jowl, jool; symbol: J) is **a derived unit of energy in the International System of** Units. … It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second.

## What is Foretriangle height?

It is defined as the horizontal distance between the front side of the mast and the intersection of the forestay with the deck. … IG is defined as the height of the foretriangle and is the **vertical distance from the mast datum point (at the sheerline at the mast) to the forestay attachment to the mast**.

## What is luff length?

Luff length is **normally set up as the distance from the tip of the mast to the bottom of the tack pulley**. So if your luff length is 454, then you’d use a 430 mast, and set your extension to 24 cm and downhaul till your pulleys are as close to touching as you can get.

## What is J in the metric system?

The joule (J) is **equal to one newton metre (1 N⋅m)**. The watt (W) is equal to one joule per second (1 J/s).

## What is a sail LP?

LP. LP is **the shortest straight line distance from clew to luff**. It’s expressed as a percentage of “J” (150% LP = 1.5 x J). It does no relate directly to area, but is a measure of overlap. For a given percentage of overlap, you get a much bigger sail on a boat with a long “J” dimension.

## How big is a yacht in feet?

To be termed a yacht, as opposed to a boat, such a pleasure vessel is likely to be **at least 33 feet (10 m) in length** and may have been judged to have good aesthetic qualities. The Commercial Yacht Code classifies yachts 79 ft (24 m) and over as large.

## How do I determine my sail size?

While the sail is still laid out go to the Tack and lay the tape along the luff of the sail as if you were extending the edge downward. **Draw an imaginary line to the intersection of where the Luff and Foot would meet** normally, this is the measurement you need.

## What size is a gennaker?

The rule of thumb for the spinnaker size is the luffs = I. The **foot should be between 1.6 x J and 2 x J**. Many cruising boats are now using “Poleless Spinnakers.” The luff on poleless spinnakers should not exceed the I or the full size genoa luff. The foot should be between 1.6 and 1.8 x J.

## How is boom length measured?

Boom lengths are taken from **the mast front to the leech edge at the upper eyelet at the clew**. The tape measure end is hooked on the sail edge just above the eyelet, letting it settle against the eyelet and outhaul line.