The centreboard (or skeg) is a tool which causes some confusion after a few hours of heaving learnt how to windsurf. Many people are unsure about when it is necessary, useful or a hinderance. This article aims to explain how and when to use the centreboard to get the most out of it.
First things first
Before we start talking about individual situations for people that have progressed beyond the first few hours of sailing back and forth I want to make one thing clear. If you are just starting out with windsurfing, use the centreboard. At all times. Our main difficulty, after managing to stay upright on the board, is to get the hang of sailing upwind.
Once you can do this and start wondering about being away and sailing downwind (rather than just drifting back with the wind), then you can start wondering about when to use the centreboard or not.
What is the centreboard for?
As I describe in my article on the physics of windsurfing, the centreboard’s function is to reduce the drag component of the sail. A quick reminder, the drag component is the one that causes us to drift sideways with the wind. Therefore, the centreboard helps us sail forwards in the direction that the board is pointing in and reduces the amount we drift with the wind.
The fin also does this so the centreboard is really a crutch for you to manage staying upwind sooner and with less effort. The ultimate goal is to be able to sail upwind without the centreboard. In any case, the centreboard will always increase how close to the wind we can sail to the wind on a closed reach, regardless of our level.
Without fin or centreboard we would drift with the wind more than what we advance across it.
When to use the centreboard
Close haul – beam reach
With this explanation in mind we can agree that it makes our life much easier if we use the centreboard to sail between a beam reach and a close hauled reach. As I already mentioned, it is still possible to sail on these courses without it but it makes life easier, especially in the initial stages.
Broad reach – running
As easy as the centreboard makes luffing up and sailing upwind, it also makes bearing away more work. To bear away with the centreboard we must lean the sail much further forward that without it and so getting on and maintaining a broad reach or even a running course. Therefore, when we are upwind and want to reach a point downwind of our position we can make life a lot easier for ourselves by retracting the centreboard.
Another thing to take into account is that the centreboard, aside from its good quality of reducing drag of the sail, it also creates its own drag due to its surface. This is an acceptable price to pay for being able to go upwind easier. However, as we don’t need it when going with the wind, the drag of the centreboard actually slows us down… another reason to retract it.
One important thing to be aware of is that at a certain speed the centreboard begins to act like a hydrofoil. In other words, it causes our board to lift out of the water. Since in the initial stages we will be going fastest when on a broad reach, this is something to keep in mind once you begin to pick up speed.
So there you have it. A brief explanation on what the centreboard is for and how to use it correctly.