A device for holding the boom up without the necessity of a topping lift.

One of the preferred is the Seoladair K1000 which runs approximately $250. This one comes with two sets of rods to provide different levels of tensioning. Depending on the exact installation location the rods may need to be shortened slightly which can easily be done with a hacksaw. Other pneumatic/spring devices are also available, for significantly more money, from Hall, Holt Nautos and Vang-Master.


  • Set the mast fitting as low in the mast track as possible. You will still probably only achieve a 30 degree angle from horizontal (as opposed to the desired 45.)
  • Remember to leave room for the outhaul fitting if it is on the boom.
  • The boom should be be slightly above horizontal when no vang tension is applied. Be sure to check with your racing main. If it is too high then your leech will twist too much even in light air. If it is too low it will not support the boom enough.
  • Some people use the heavy rods, others use the lighter ones. The manufacturer suggests that you start with the heavier ones.

Interactions with the Vang

  • Use a multiple purchase vang, 3:1 mast-to-boom, 6:1 end of boom-mast for a total of 16:1.
  • Use a 16:1 vang lead back to the cockpit (really helps out the fordeck guy).
  • Make sure the vang is TOTALLY SLACK with lots of sag when going upwind.
  • If there is too much kicker without any vang, the leech will open when the boom is forced up, requiring un-needed vang tension to counteract the force of the kicker.
  • However, there is also the opinion that vang tension to counteract the force of the kicker downwind is not bad, its good, its what you want to stablize the sail. Upwind, its the mainsheet that controls leech tension, the only thing the kicker does is provide a little more resistance. Once you ignore that you are sailing to the telltales again. The vang does need to be fully released upwind as you can overtension the main with the vang as you ease the sheet, and not realize it.
  • Note: Some confusion in terminology for different parts of the world. The word "Vang" and "Kicker" in the UK, Europe, Africa and Australia/New Zealand mean the same thing (the device that holds the boom down). In these countries they refer to the the device that tensions/releases the foot of the main as an "OUTHAUL" and the tackle used to increase luff tension on the mainsail is called a Cunningham.

See also

  • Blackadder
  • Jambo
  • Shade of Avalon
    Smackwater Jack
  • Tesser