Is there a unsafe speed for a sail boat?

Answer 1

Monohulls have a maximum hull speed that they will simply not sail faster than - while the hull speed of a particular vessel may be slightly more or less than the estimated hull speed, based on unique characteristics of the hull, this number is still, essentially, a constant. The following formula is an estimate of that hull speed.

Hull Speed = 1.34 * (LWL)1/2 where LWL is the length of the hull at the waterline.

The hull speed is, we should note, the speed *through the water* - ie., if you are travelling down a wave or with a current, your speed relative to shore may be higher.

A multihull boat - like a catamaran or a trimaran - is most often exempt from this limitation because they are non-displacement or "planing" hulls: that is to say, that as a catamaran goes faster, it lifts farther out of the water. At very high speeds, this can result in instability and control issues, though with larger cats it's fairly uncommon or them to actually tip over.

The maximum safe speed, however, is largely one of conditions: sea state, wind speed, and the experience of the captain and crew.

To answer your question another way: there's an unsafe speed for *anything* - depending on conditions and surrounding obstacles - but the dangers involved in sailing are mostly not associated with exceeding any sort of imaginary speed limit.