How to Trim Sails Downwind

    Published: 06-16-2009
    Views: 16,006
    Kevin Wensley, Director of Operations of the Offshore Sailing School, demonstrates how to sail trim downwind.

    Kevin Wensley: Hello! My name is Kevin Wensley. I am Director of Operations at Offshore Sailing School and today I am at South Seas Island Resorts on beautiful Captiva Island here in Florida.

    What I like to do today is talk a little bit about sailing a boat downwind and how to set your sails up for that. So the first thing to do is to sail your boat, steer the boat in a downwind direction with the wind coming over one of the back corners of the boat.

    Then look to your jib, with your jib sail you want to ease the sail out looking towards the head of the sail and as you are easing out make sure that the top of the sail doesn't twist open too much and you start to spill air off the top of the sail. So if that happens, just roll the sail back in again until it fills completely.

    The key to sailing well downwind is maximizing sail area exposed to the wind. So our mainsail gets eased all the way out. We don't particularly want the boom to touch the shrouds, but we don't mind if the sail touches the shroud.

    So with the boom eased all the way out, we can then look again to the head of the mainsail to make sure that isn't twisting open. And if you find that you are spilling air over the back edge of the mainsail, what we need to do is pull down on our boom vang and the boom vang will then close the leech of the mainsail.

    The last thing to think about is to give the mainsail a little bit of a pocket shape. So if you've been pulling tight on your outhaul for example, you want to ease that a little bit just to open up the foot, and also if you've been using the backstay, ease up on the backstay and perhaps the cunningham as well.

    Now once you've done that, then you got to think about how to steer well downwind. If we steer the boat too far downwind, what you'll see happen is that the jib gets blanketed by the wind shadow of the mainsail and we don't really want to do that.

    If we sail even further downwind, if we go dead downwind you can't actually bring the jib across to the other side of the boat, so we have mainsail on one side and jib on the other and that's called sailing wing-and-wing.

    If we really want to increase sail area, what we can do is we can put the spinnaker out. So here at Offshore Sailing School even in our Learn to Sail Courses, we like to demonstrate that. So up goes the spinnaker and as you can see it's going to add a significant amount of sail area to our sail-plan.

    And so that's how to set your sailboat up for sailing well downwind.