PolySail International

High Performance/Low Cost Sails for Small Sailboats

 

 

LATEEN SAIL

The lateen is a tried and true sail that often powered the merchant dhows that plied the Eastern Mediterranean in ancient times. Today, the lateen is a popular sail used in recreational sailing on dinghies such as the popular Sunfish. The triangular lateen hangs from a long yard on a relatively short mast. On larger commercial boats, the forward end of this long yard might be tethered to the bow of the boat with a line run through blocks to help control the angle of the yard. On these boats, still used in commerce on the Mediterranean today, the large sail is normally loose-footed. On today’s dinghies, however, there is usually a boom along the foot that is joined to the yard at the forward ends of these spars. In the photo below, the PDRacer on the right with the blue sail is powered by a lateen sail.

 

 

On small, short boats, such as Marc Blazer’s Bloody Splinter PDRacer pictured above, the lateen has several advantages over other types of sails. The Center of Effort for this sail is lower when compared to other triangular sails and some of the sail is carried forward of the mast. Both of these factors allow a lateen-rigged boat to carry more sail than another small boat rigged with a single triangular sail. Because some of the sail body extends beyond the mast, the mast can be placed further aft than with many other sail types. On a boat like the one pictured above, the mast placement allows for a deeper mast bury and a more stable mast than other boats might carry. Another advantage to the lateen is the ease of stowing the sail. A halyard raises and lowers the yard, and when lowered, the yard and boom can be aligned with the boom then the sail wrapped around the three sticks to make a nice package for transport or storage. On the negative side is the weight imparted to a lateen by the need to carry both a yard and a boom aloft.

 

One of the biggest advantages of the lateen sail for small boats is its ease of construction from polytarp. Using a lightweight polytarp, nearly any lateen from 50 sq. ft. to 75 sq. ft. can be constructed by rounding the luff by 3” to 3 1/2” at about 45 % up the yard from the tack (front corner) of the sail. Round the foot by 3 1/2” to 4” at about 35% of the boom back from the tack. Hollow the leech by 2” at the midpoint of the leech and your lateen sail shape is complete. Below is a diagram of a 70 sq. ft. lateen sail that you can make from one of our 12’ x 16’ PolySail Kits that will fit on a number of small dinghies.

After laying out the sail to these dimensions, click here – Instructions – or on the “instructions” tab at the top or bottom of the page to go to our directions for completing your lateen polysail.  If you make this sail from lightweight polytarp, no dart is needed at the tack. With a heavier weight of polytarp of 6.0 oz. or more, a long narrow v-dart of about ¾” finished width can be added at the tack for greater camber.

 

Below are some photos of lateen sails that PolySail International has made for Kiwi and Catbox PDRacers.

Welsford Kiwi lateen, 55 sq. ft.

Herring lateen. 65 sq. ft. variation of the Kiwi lateen

70 sq. ft. Catbox lateen, made specifically for Jim Michalak’s personal PDRacer from his design.

 

I suggest bamboo or aluminum spars for lateen sails. The spars need a hinged or somewhat flexible joint at the heel of the boom and yard to function well. Below is a photo of PDRacer #2 with a lateen featuring aluminum spars and captained by Bill Giles in rough conditions at Rend Lake, Illinois. A close look at the sail shows why some hollowing is needed in the leech, but otherwise, this lightweight polytarp sail is virtually shaping itself aerodynamically.

 

 

 

PolySail International

2291 SE Gaslight St., Port St. Lucie, FL 34952-7332

 Email polysail@polysail.com or call Dave Gray at 317 385-3444

PolySails–Sold on the Web since 1996. Customers in all 50 states and around the globe.

 

This page updated on 1/1/2011