Garth's New Winged Centreboard

Launching the boat means firstly tipping boat on its side in the water. The centreboard slides into the normal centrecase from the bottom of the hull and is pinned through at the deck with ¼” toggle pin. Then the cable from the sensor arm attaches to the centreboards control rod with a simple ball and socket snap together fitting. The sensor arm and cable always remain on the hull so overall rigging actually takes no longer than a regular moth.

Upwind the boat does not appear to be fully foiling but I feel that it actually is. The bow sits just clear of the water with the full stern still contacting the wave tops. Even though the boat is not out of the water the foils are still carrying the majority of weight. Wetted surface is reduced and as the weight is on the foils the boat does not pitch with waves.

Reaching is of course the best part. Whilst the rudder has a controllable flap we have found that this does not need to be used at all. With the height automatically controlled there is nothing extra to do with regard to flying the boat. In 12 knots of wind the boat will lift within a few boat lengths, then everything goes quiet. The ride is quite smooth and very fast.

Downwind or generally sailing deeper is a little different to straight reaching. The helm needs to try and maintain constant pressure in the rig by following the apparent wind through changes in the wind strength or direction. Not too much different to a skiff with a kite up, you fall of the foils instead of falling off the plane. This Tee foiler gives the sailor a lot of confidence sailing downwind. With the foils being below the water there is no influence at all on the boat from the surface waves and the ride is super smooth. It does feel pretty strange at first, sailing deep downwind crouched on the deck near the centre of the boat.

New Sensations
Obviously there are a few that are strange or different to become accustomed to. Firstly steering at up to 15 knots of boat speed is ok but at higher speeds the steering just becomes very sensitive and tends to knock your confidence a little. Sailing into lull in the breeze is also strange. As the wind drops, so does the downward pressure of the rig on the boat and so initially the boat will actually fly a little higher before coasting down to the water surface. It always seems as though you are landing a seaplane as you become so accustomed to there being almost a silence. With the landing you feel you can relax again as focusing on steering for long reach can be a bit taxing on your mind.

So far the worst that can happen results when sailing into a sharp gust of wind. Should the gust freak you a little and you sheet out the sail, then this will also decrease the downward pressure on the boat which ends up with skipper naturally/defensively rounding up into the wind as the boat tries to launch it’s self out of the water. You rarely end up having a swim but you will see the centreboard foil break the water’s surface as it all stalls and lands back in the water.

First Days
Initially things did not work so well. While the system is really simple to rig and operate there are actually quite a number of moving parts. It took almost three months sailing most weekends to tune it, adjusting cables and ratios within the linkage and also a diamond saw to cut and modify the foil. It did foil on the first day out in very minimal wind but then on another in around 20 knots wind there was a big crash at speed from a fair height.

More Information

Contact John Ilett on john@fastacraft.com.