Torpedoes and bulbs will be a topic of conversation in Kinsale this week at the Sovereign's Cup. The much sought after Kiwi Quarter tonner, Black Fun that competed in last week's ICRA Nats is entered for the regatta and eagle eyed photographer Bob Bateman snapped the quarter tonner in the Royal Cork boat park.

Acoording to Wicklow based yacht designer Mark Mills, the magic behind any bulb is in separating the two functions of a keel: low vertical centre of gravity (vcg) and lift. A fin keel usually by the time it has enough lead in it for stability will be larger than required for lift (see the standard 1/4 ton keel). The bulb gets one job done by getting the most weight down low, while the fin can be sized for the right amount of lift - as long as that is enough to keep the bulb attached.

Bulb keel technology on Black Fun

Black Fun puts her bulb to good use off Roches Point