November 7, 2003

  • Portsmouth Number

    The higher a boat’s D-PN rating, the slower it is. D-PN ratings are used to calculate a boat’s handicap when boats of different classes are raced against each other.

    That’s why, when you’re in a regatta and sailing in a West Wight Potter coming over the finish line a whole hour after an E-Scow whizzed past your ass with its skipper blowing you a raspberry, you can still finish in 1st place, and have the last laugh.

    A West Wight Potter has a D-PN rating of 135.8, which probably puts it in place for being one of the slowest boats in existence.

    wwp
    West Wight Potter

    An E-Scow has a D-PN rating of 73.2, which means that if it took the E-Scow 73.2 minutes to run a course, then a West Wight Potter that was sailed with the same skill would come in 62.6 minutes later (135.8 – 73.2).

    e-scow
    E-Scow

    laser
    One of the first Lasers, originally called a “Weekender”!
    (from http://www.lasersailboat.com/history.php)

    Lasers are pretty popular cartoppable boats. And it’s no wonder. If you like speed, a traditional Laser has a D-PN of 91.3. (A Laser M has a D-PN of 93.2. I don’t know about Laser IIs. . . .)

    My Banshee has a D-PN of 94.3, which is plenty fast enough for me.

    Both the Laser and Banshee have loose-footed sails, which I personally think allows the sail to achieve a better shape. Improved sail-shape probably explains the unusually low D-PN for boats of their small size and light weight.

    The One-Design 14 is a fast, small boat with a proud D-PN of 88.2. However, the fact that it weighs > 200 lbs. makes it a little less than ideal for cartopping with a compact car.

    It’s amazing to me how even in sailing, people fall into class-design cliques. Every design has it’s own purpose, drawbacks, and advantages. Each class attracts its own personality of people.

    But no matter what class of boat, I really admire women who’ve worked hard to buy the boat of their dreams, and who don’t sail for money or love.

    More on Portsmouth Numbers1
    (at http://offshore.ussailing.org/Portsmouth_Yardstick/Portsmouth_Yardstick_Index.htm)

    References:
    1 Updated 08/06/11, as http://www.ussailing.org/portsmouth/ no longer works and has been changed to http://offshore.ussailing.org/Portsmouth_Yardstick/Portsmouth_Yardstick_Index.htm