Here is how we define them at North Sails. I – Height of Foretriangle. Elevation of Forestay, measured down to elevation of main shrouds at sheer line. J – Base of Foretriangle. Horizontal distance measured from front face of mast at deck to position of headstay at sheer line.
What is the J dimension?
“J” Dimension
Measure the horizontal distance between the tack fitting and the mast. This is the “J” dimension and will be the number the “L/P” is compared to for percent overlap.
What is the J dimension of a boat?
"J" is the base of the foretriangle measured along the deck from the headstay to the mast. "JC" is the greater of the following three dimensions: "J", the length of the spinnaker pole, or the maximum width of the spinnaker divided by 1.8.
How do I determine my sail size?
What Sail Dimensions are Required to Calculate Sail Areas?
- The required sail dimensions for calculating the area of any triangular sails are usually its height and the length of its foot. ...
- Area = (P x E)/1.8, where:~
- For the mizzen sails on ketches and yawls, 'P' and 'E' relate to the mizzen mast and boom.
What are the numbers on sails?
There are four types of sail numbers, and they all get issued by different parties:
- Factory numbers - issued by the builder.
- Class numbers - issued by the class association.
- International numbers - issued by the national authority.
- Creative numbers - issued by you.
What do the letters on a sail mean?
sort of: "I" indicates the vertical hoist of the jib/headsail. "P" indicates the vertical hoist of the main. "J" indicates the horizontal distance between the tack fitting and the front of the mast. "E" indicates the horizontal distance between the gooseneck and the clew of the main.
How do I find my GBR sail number?
To apply for a Sail Number for your windsurfer please contact [email protected] or phone 023 8060 4200 and have your RYA membership number available.
What is the difference between a genoa and jib?
A jib is a foresail that does not extend aft beyond the mast; a genoa, on the other hand, is larger and will overlap the mast and part of the mainsail. A jib sail is used for strong winds and is easy to handle, while the genoa is perfect for downwind sailing in light winds.
What size jib do I need?
The jib size as expressed as a percent is found by dividing the "LP"(luff perpendicular) by the "J"(distance from the front of the mast to headstay along the deck) dimension for that particular boat. For example if the LP was 15' and the J was 10' then 15/10= 1.5.
What is the height of a sail called?
The hoist of a sail is its height on the mast. 1.
How tall should a sailboat mast be?
As a general rule of thumb, the height of a boat's mast will be somewhere between 1.25 to 1.35 times the boat's length, for an average of about 1.3 times the length overall (LOA) of the boat. An aspect of 2.5 or lower will be a low-aspect rig; above that is considered a high-aspect ratio.
How do I measure my mast?
Measure the distance it hangs behind the backside of the mast. E Measurement: Measure from the backside of the mast at the gooseneck, along the boom to the location of the clew. If the boat has a black band to mark this location, measure from the backside of the mast to the inside edge of the black band.
What is sail area?
The nominal sail area is calculated as the sum of the foretriangle area (one-half the base, or J dimension, multiplied by the height, or I dimension) and the mainsail area (one-half the foot, or E dimension, multiplied by the hoist, or P dimension).
What is luff and leech?
Luff -A sail's forward edge. The luff of the mainsail is usually hoisted up and attached to the mast. The luff of the jib is attached to the forestay. Leech – The sail's back edge.
How is spinnaker sail area calculated?
singlehander with jib
The area of an actual headsail is measured by striking a perpendicular from the luff to the clew and multiplying that length by the length of the sail's luff. Under the International Offshore Rule, the base length for that perpendicular was J, expressed as LP = J.
What is a staysail on a sailboat?
A staysail ("stays'l") is a fore-and-aft rigged sail whose luff can be affixed to a stay running forward (and most often but not always downwards) from a mast to the deck, the bowsprit, or to another mast (the mast is item 13 in the illustration right).
What is a number 1 genoa?
Genoas are classified by their size; a modern number 1 genoa would typically be approximately 155%, but historically number 1 genoas have been as large as 180%. Number 2 genoas are generally in the range of 125–140%. Working jibs are also defined by the same measure, typically 100% or less of the foretriangle.
What is a screecher on a sailboat?
A screecher is specifically a multihull term for a very large, very flat sail for going upwind or just cracked off. Catamarans and trimarans have notoriously small jibs, making them grossly underpowered in light breeze. A screecher is larger, higher clewed, and fuller than a genoa but flatter than a typical code zero.
How do I identify my sailboat?
The type of sailboat is always determined by one of these four things:
- The type of hull.
- The type of keel.
- The number of masts.
- And the type of sails and rig.
How do I get a laser sail number?
Where is your sail number located
- For Laser sailboats built after 2010 the sail number is located in the rear of the cockpit on a sticker.
- For Laser Sailboats Built Prior to 2010 the sail number can be decoded from the Hull Identification Number Located on the stern or on very early lasers under the bow eye.
Is mast height measured from the waterline?
Mast height is almost always measured from the water. But to be sure you know the how high the top of your mast is from the water, measure the actual height of the mast from the deck to the top of the halyard (tape measure) and then add a foot to account for the sheeve typically being below the actual top of the mast.
How do you measure the height of a sailboat?
How to Measure Your Boat for Transport
- Overall Length is measured from the tip of the bow to the center of the stern. ...
- Overall Height is measured from the bottom of the keel to the highest non-removable part of the boat.
- Beam is measured from the widest point of the boat, including the rub-rail.
