Ericsson Racing backgrounds keel failure

by Ericsson Racing Media on 30 Nov 2005 Last night, Ericsson was reaching at 20 knots, in 22 knots of wind, when a failure occurred in the keel movement system. The boat had to be stopped to allow the crew to inspect the damage. Ericsson is now sailing towards Cape Town under reduced sail to avoid overloading the system. The crew is in no danger.

Instead of using water ballast, as in previous constructions, the Volvo Open 70 yachts’ keel can be angled 40 degrees into the wind, counterbalancing the yachts’ heeling angle much more effectively than traditional keels, which means that more sail can be hoisted, meaning greater speed, which in turn means greater loads on the entire system.

Swing keels are not new, but it is the first time that the system has been used on such extreme yachts as the VO 70s under such extreme conditions. The swing keel is governed by two hydraulic cylinders, that push and pull respectively, and is fixed inside the cylinders by a fork that transverses the keel’s head where a hole for each mount has been drilled and fixed with a pin.

The cylinder is then fixed to the hull with an articulated mount. The safety regulations state that the yacht must be able to continue sailing even if one of the cylinders is malfunctioning. The keel is 4.5 metres long with a lead bulb on the end. The distance from the pivot point to the hydraulic cylinders is around 50 cm. This means that the upper short arm needs to have ten times as much load-bearing capacity as the lower arm.

The details of the reasons of Ericsson’s keel problems are not known yet. The system will be thoroughly investigated once the boat arrives in Cape Town.