Seaworthy keels

MOST modern sailboats are not designed to be the most seaworthy vessels on the open ocean. They're designed as coastal cruisers, whose characteristics make them lighter, faster, more closewinded and often roomier below.

The old rule of thumb is that a boat with a long, traditional type of keel is more resistant to capsize than is a hull with the coastal cruiser's deep, narrow fin keel. At least, that holds true when neither yacht is making way through the water.

A yacht at sea is a dynamic system that receives most of its overturning energy from waves. A traditional keel and hull shape are effective at dissipating this energy gradually, absorbing the blows of the seas more gently.

A fin-keel boat has less underwater area in which to pass the energy on into the sea, and is more vulnerable to capsize when lying still in the water. But a fin-keeler becomes more resistant to capsize if she is kept moving, and can thus dissipate the incoming wave energy into a greater area of water.

A traditional cruising boat, having a more effective roll-damping keel, can better look after herself when lying almost still in the water, or hove to.

Tony Marchaj, a small-boat sailor who is also an internationally renowned aerodynamic and research scientist, says the keel of a truly seaworthy boat should be designed primarily for the survival situation (that is, zero speed) which implies a traditional keel with large lateral area and depth of the hull underbody.
In his book, Seaworthiness: The Forgotten Factor, Marchaj quotes a former editor of Rudder magazine, T. F. Day, who crossed the Atlantic in 1911 in the 25-foot yawl Seabird:

"My long experience in small boats has taught me this: that if a boat is a good boat, when real trouble comes she is best left alone. She knows better what to do than you, and if you leave her alone she will do the right things, whereas nine times out of ten you will do the wrong thing."

Today's Thought
Extremely foolish advice is likely to be uttered by those who are looking at the laboring vessel from the land.
--Arthur Helps, Friends in Council

Tailpiece
Middle age is when you find yourself doing one bend-over to pick up two things.