Monday, 14 May 2012

Long Keel, Short Keel Bilge Keel – Which One Is Best?

Keels can be heaven or hell – to the owner of a high speed power boat a keel is the last thing you would want. Keels make your boat heavy, they increase the wetted area of the hull, they cause friction and slow you down. On the other hand boats without a keel pay a different price, they have no grip on the water so when engine power is reduced they are difficult to control slipping and sliding in any direction at the merest hint of a breeze. From a more traditional boat owner’s point of view keels are necessary because they bite the water, reduce leeway and help keep the boat upright. A sailing boat without some form of keel would only be good for down wind sailing. Given their importance it is hardly surprising that they get a significant amount of attention from designers.

A traditional long keel can be ideal if you rate an easy motion and directional stability above speed. Long keeled boats look after their crew, they are ‘sea kindly’. A long keeled sailing boat will often follow a set course for hours without needing attention at the helm. She may be the ideal choice for long distance, blue water, short handed sailing but she’ll be slow.

Modern racing yachts tend to have a short fixed keel or a retractable dagger board, deep in the water when fighting to get upwind and raised to reduce friction when running downwind.  These are fast highly manoeuvrable craft. They win races but they buck and heel to every gust of wind or slap of the wave. Boats such as these are exciting but they keep their helmsmen busy.

Bilge keeled boats have two keels, side by side. They were developed not so much to improve performance but rather to reduce the cost of boat ownership. A bilge keeler is able to sit upright on the mud so it makes cheaper, half-tide moorings a more attractive prospect. Many early bilge keelers were poorly designed so they were neither fast nor sea kindly. They have improved over the years – but they are still considered to be a compromise solution.  So, which type of keel is best? for. It all depends on what you want your boat to do, how far you want to go and how much you’re prepared to pay.

From my point of view, bilge keels will give shallow draft, so they would be good for getting through the canal. They’ll also give me a chance of staying upright if I accidentally ground on a mud bank in the estuary. A long keel is attractive for directional stability and a steady predictable movement in a seaway. I’d rather do without a retractable keel if it means giving up cabin space to its housing and anyway, it might be a bit too sporty – I want a boat that will look after herself while I pop below to put the kettle on, fin keelers have the reputation of doing their own thing the minute you take your hand off the tiller.  A recent comment from Michael (yesterday) however, set me thinking about triple keels, or at least two bilge plates and a skeg, and he mentioned one boat ( too staid for him) but possibly quite promising for me!


David Greenwood