Theres a misconception I come across quite a bit that you can add weight and windage and youll still be fast as long as your hulls are fine.

Catamaran hull speed. It depends on the hull shape how heavily loaded the boat is the sail plan and about a dozen other factors. Hull speed or displacement speed is the speed at which the wavelength of a vessels bow wave is equal to the waterline length of the vessel. Fine hulls are fast but only in the higher speed range.

Deciding between a catamaran and a monohull is a big decision and one worth considering well before taking the plunge. Personally I find the most important benefit of speed of a multihull is the ability to outrun bad weather. Half overall beam half hull beam racing cat Stars and Stripes had a 161 HFR.

When planing a monohull will exceed its hull speed. There are also catamarans that are designed for wave piercing. The hull speed formula for displacement monohulls is 134 x the square root of the waterline length.

Having sailed on both and built then lived for 5 years on a catamaran in this post I want to share with you my impressions and thoughts on safety costs speed stability and other advantages and disadvantages of sailing. The most important catamaran design hull shape factor is the Prismatic Coefficient Cp. The famous victory of the Americans with their small 60-foot catamaran facing the New Zealanders and their big 90-foot monohull at the Americas Cup in 1988 is a good example.

On average cruising catamarans can reach top speeds of 15 knots around 173 mph 2784 kph. While a standard boats performances are limited by her maximum hull speed multihulls and racing yachts are able to go beyond this speed. Of course the larger the boat the narrower the hulls will become in comparison to its length.

Still cruising catamarans are very comfortable boats and they are excellent for people who want both speed and the luxuries of a cruising boat. The concept of hull speed v 134 sqrt LWL for waterline in feet v in knots assumes that the boat is essentially limited to the speed of a wave thats as long as the hull- a rough at best approximation for monos and almost meaningless for cats. Obviously this formula doesnt apply to catamarans.