Most tuning guides for centerboard dinghies and scows tell you to raise your board 1-2″ in heavy air. In this post we’ll briefly discuss three reasons why this is important.
This post updates our previous post on setting leeboard height to reduce windward helm. Reducing windward helm is the main reason to raise boards, but there are two other effects to consider.
Raise Your Board in Heavy Air – Three Reasons
#1. Reduce Windward (Weather) Helm
Raising the board moves the center of lateral resistance aft. This helps balance the helm, since the center of effort tends to move aft in a breeze. For more on this topic, see our post Manage Upwind Helm Balance for Speed and Feel.
#2. Reduce Board Drag
The board provides hydrodynamic lift to keep the boat from side slipping. To provide adequate lift at slow speeds, you need more board area in the water as well as a slightly lower heading to give the boards a greater angle of attack.
As the boat gets up to speed, the lift from the boards increases dramatically. If your boat speed doubles, the lift from the board quadruples! In heavy air, you have more than enough board lift, which also causes excess drag from the board.
To counter this excess drag, you head higher to reduce the angle of attack and raise the board to reduce its underwater area. The boat will feel freer and faster.
#3. Reduce Over-Heeling
The underwater lift on the board makes the boat want to heel. Imagine a sailboat with sails down being towed by a powerboat. If you lowered the board while being towed and steered the boat a few degrees off center, the boat would heel up due to the underwater lift. When sailing upwind, heeling is caused by both the force of the wind in the sails and the underwater lift from the board.
With too much wind and the board fully down, it’s easy to over-heel and risk a capsize. To control heel and avoid “tripping” over the board, raise the board a few inches, as discussed in your boat’s tuning guide.
Try Raising Your Board Before You are Overpowered
Several top sailors have told us they raise their board before they are overpowered. See this interview with MC Scow sailor Mike Kaiser. Mike adjusts the board height based on wind conditions and feels this gives him an edge on sailors that only raise the boards as a last resort.