The D4 Process

The D4 Mainsail is manufactured utilizing a taffeta and clear UV film for ultimate durability. The UV film reduces the exposed light, which can lead to fiber breakdown. This sail will provide the ultimate in durability and shape holding.

The fibers used offer incredible thread line strength and efficiency, essential to handle the high leech loads of a large mainsail. The D4 layout is superior to any other process. Additional fibers can be placed in any area of the sail for added strength.

D4 Layout - 18,000DPI
High Modulus Twaron
Clear UV Film
w/ Single Taffeta

The race jib is called on to fill a very broad performance range. The D4 race jib is manufactured using 100% HM Twaron. Additional yarns are placed in the leech area to add additional strength. UV films are also used for increased durability.

There is no question that this sail is used in all of the large regattas and extensively throughout the racing season. Removable battens are incorporated in all the jibs to facilitate transporting the sails. In addition, this sail is built to the Class maximum girth.

D4 Layout
18,000 High Modulus Twaron
UV Protective Films

Doyle Boston Sailmakers
120 Michigan Ave.
Pt. Edward, Ontario
Canada N7V 1E6
Tel (519)344-5236