Catamarans reduce drag by making use of a very thin and pointed hull design.

Catamaran hull planing. Lower values 057 are optimized to displacement speeds and higher values 060 to speeds over the hull speed hull speed. Thus catamaran hull forms range from pure displacement up to real planing hulls. Oddly power needed and efficiency are not much better than single hull planing craft at planing speeds.

C p is typically between 055 and 064. I guess Yves Parliers boat is the most famous of these. Since these hull shapes are associated with operation at high Froude numbers the use of Hydrofoils is very applicable to these hulls.

It displaces water at low speeds but is able to generate lift at cruising speed. Planing Catamaran The planing cats ride is still rough compared to dis-placement cats but better than on a planing single hull boat. Feb 3 2020 - Explore Keith A Daviss board Catamaran Hull Design on Pinterest.

It also helps to keep the rocker straight for most of its length and smooth the water flow exiting the hull aft at higher speeds possibly promoting some planing effect. Planing hulls can exceed hullspeed by lifting over the water and planing at speeds well exceeding hull speed. They claim it worked very well under the right conditions until it crashed and burned.

Catamarans and other multihulls are rounded shapes and narrow so they cannot plane like a flat bottomed. The design is then usually driven by the demand for a large and stable working platform high transverse stability and shallow draft where speed is not so important eg. Catamaran hulls can be designed as planing or displacement hulls but they are not slowed nearly as much by the drag barrier.

In order to achieve planing speed adequate dynamic lift must be gained to. The same separating effect is desired from the transom stern. The top speed of these craft again are only dependant on the amount of power applied.