User:Gmroaming/sandbox

Introduction
HYSUCAT is an accronym for HYdrofoil SUpported CATamaran and describes a seagoing catamaran that has a hydrofoil system of a very specific arrangement mounted in the tunnel between the two demi-hulls. At speed the hydrofoil system supports part of the vessel weight, with the remainder being supported on the hulls. The HYSUCAT was invented by Prof. Dr-Ing. K.G.W. Hoppe of Stellenbosch University in South Africa in 1980. It was developed to fulfill a requirement of the South African Navy for seaworthy small craft for navigating the rough offshore conditions off the Southern African Coast. Since the first 5.5m HYSUCAT was launched in 1980, in excess of 500 HYSUCATs have been produced worldwide ranging in sizes from 3.5m to 36m.

Typical applications include:
 * Yachts and leisure craft
 * Fast passenger ferries
 * Patrol Boats
 * Rigid inflatable boats (RIBs)
 * Work Boats of various types (survey vessels, crew transfer vessels, excursion boats, water taxis...)

The HYSUCAT Principle
The HYSUCAT principle stems from combining a planing catamaran hull with a hydrofoil located in the tunnel formed by the two demi-hulls of the catamaran. The resistance of the HYSUCAT is reduced compared to conventional planing hulls due to the more efficient hydrofoil carrying part of the vessel weight. A typical planing hull (monohull or catamaran) as a lift to drag ratio of: L/D = 4-7. A hydrofoil of size and type used on HYSUCAT craft has L/D = 20-30. The hydrofoil is considerably more efficient at carrying load than a planing hull and therefore supporting part of the boat's weight must improve the overall efficiency of the boat. The challenge lies in in choosing a suitable configuration of hull and hydrofoil that provides:
 * improved overall efficiency
 * adequate stability at high speed and in waves
 * good handling and maneouvering characteristics
 * a good practical configuration that does not impare the operation of the craft (i.e. little or no increased draft and beam for the boat)
 * a configuration that does not add undue complexity to the craft

Significant research was conducted at the Stellenbosch University, Dept. of Mechanical Engineering ship model test basin to establish the optimal configuratiosn of hull and hydrofoil systems. The normal HYSUCAT configuration consists of an asymmetrical planing hull with a main hydrofoil located forward of the Longitudinal Centre of Gravity (LCG) and two smaller stern hydrofoils located close to the transom of the boat. The hydrofoil system is designed to support 30-60% of the vessel's weight (the remainder being carried by the hulls). The hydrofoil system lifts the hull partially out of the water which has the beneficial effect of reducing the resistance of the vessel.

Main Benefits
Making use of a HYSUCAT compared with a non-foil assisted catamaran has the following main benefits:
 * Increased speed by 20-40% (for equivalent power)
 * Reduced power requirements 20-30% (for equivlaent speed)
 * Reduced Wake Wash (wave height & wave energy) by 10-30%
 * Reduced vertical accelerations by 30-50%
 * Improved seakeeping characteristics

===