Wedged up

We look at Ecover's secret design feature

Not always evident when one is clambering around a boat tied up to the dock are some of the subtleties of its hull shape. We should have known better with the crafty former Team New Zealand designer Clay Oliver involved... for beneath the transom of Mike Golding's latest Ecover Open 60 there appears to be some form of shallow wedge which is presumably a device to encourage planing.

Two of the new Farr designs, Jean-Pierre Dick's Virbac Paprec and Loick Peyron's new Gitana 80, are fitted with a giant planing board (read more about this here) but they are very much more extreme than Ecover's set-up - around 1m fore and aft - and (like Ecover's wedge) extending around the full perimeter of the final run aft. But, significantly, the Farr boats' planing board can be articulated up and down to alter the path of the water passing beneath the transom. In their case the board is used in conjunction with the water ballast to alter fore and aft trim. For example there are occasions such as upwind in light airs when you want to maximise waterline length, but don't want to weigh the boat down by bringing on board water ballast. In light winds off the wind, the planing board is raised to minimise draggy transom immersion. However on Ecover the shallow wedge appears to be there permanently.

Many people in the Open 60 community are referring to Ecover's top secret feature as an 'interceptor'. Like the planing board/trim tab, this is another feature from the motorboat and commercial shipping design world where it is used to alter fore and aft trim. Typically on a motor boat or a ship, an interceptor is a flat plate that drops down vertically so that its bottom extends just below the transom (by just a few centimetres). The effect of this is similar to a trim tab - water travelling down the hull hits this lip (in this case the water is presented with a flat face) and as it strikes it creates lift. Despite seeming to be quite draggy, the interceptor is in fact believed to create lift in a more efficient way than a trim tab/planing board.

So on Ecover what exactly does it do? At present the team and their designers are keeping their mouths shut...

Theories please - here