Articles: The big three of flat genoa trim

Article by 2001 J/24 Midwinters Champion Tim Healy

As I pulled onto I-95 north, heading home from the 2001 J24 Midwinters held at Davis Island Yacht Club, I let my mind wander back to the racing of the past few days. Somewhere around Lumberton South Carolina, I started to think about what changes we had made in our sailing that allowed us to maximize our boat speed in the flat water we experienced on Tampa Bay. I realized we had concentrated on three important tuning and trimming adjustments: rig tension, genoa halyard tension and genoa lead position. Here are a few tips on how to use these adjustments to get the most out of your speed in flat water.

The first adjustment to consider is rig tension. When in doubt of the proper rig tension setting, err on the tight side. This allows for consistently faster, flat-water genoa shape, i.e. flat, draft forward shape with a straight exit. Flatter sails are fast in flat water because the boat does not have to go through the constant acceleration and deceleration that is normally experienced in lumpy conditions. Therefore, a saggy headstay and deep genoa are not necessary. Also, with a tighter rig the mainsheet tension does not have such a dramatic effect on the headstay, and the backstay can be left alone longer (fewer adjustments). When the boat is tuned properly you should not have to start to use the backstay until everyone is hiking hard.

The second adjustment is the genoa halyard tension. The halyard needs to be set before the genoa lead position because the halyard changes the sheeting angle regardless of lead position. For example: When the genoa halyard is pulled up it moves the whole sail higher and the sheeting angle changes as if the lead was moved forward. If the halyard is lowered the sheeting angle will change as if the lead was moved aft. Now, because we have adjustable genoa leads to control the sheeting angle on a J24, what we are adjusting with the genoa halyard is luff tension. A slightly tighter-than-normal luff will help create the desired draft -forward, straight-exit genoa shape.

Finally, the genoa lead is ready to be set. Two fixed points from which to measure genoa trim are the spreader tip and the shroud chainplates. In flat water, set the lead to a position where the genoa foot is touching the chainplate and the mid/upper leech is 1" off at the spreader tip. This lead position will allow you to sheet harder without stalling the upper leach and it will create an overall flatter genoa shape. This lead position should not be a big move back from your median genoa position (less than 1" back). The median genoa lead position should be placed where the genoa trims to "even, even", which means that when the genoa is sheeted in it is an "even" distance from the spreader tip and the shroud chainplates. The range of adjustment on your genoa leads for all conditions should only be about 2-3" from the most forward position to the most aft position.

Next time you find yourself racing in flat water, pay close attention to the above three adjustments. However, be careful not to overdo it; all the adjustments mentioned above call for subtle changes. When the rig tension, genoa halyard tension and genoa lead position are set correctly for flat water, your newfound speed will help you break away from the pack.