Green Technology

Catamaran Hulls

Catamaran-type hulls are not new – they have been in use in ship-building since the Polynesians with their twin-canoe hulled sailing vessels dating back about 3000 years.  They probably exploited many of the hull-type’s unique characteristics by creating wide, stable, seaworthy and easily powered vessels.  The advantages of the catamaran hull-type include:

  • Useful Deck Size: A power catamaran hull typically creates a deck that is 25%-30% wider than a similar length monohull.  This additional, usable deck space allows additional cargo loading area for commercial vessels, more passenger seating space for ferries and more interior/deck/cockpit space for leisure vessels.
  • Seaworthiness: The ride-comfort of a catamaran hull is significantly better than a monohull in any sea-state (other than dead calm where they are both similar).  The high slenderness ratio of the individual hulls allows them to punch through waves resulting in lower vertical accelerations which are perceived as a softer and more comfortable ride.
  • Safety: Due to their wider beams and buoyancy being largely concentrated near the beam limits of the vessel, they have a higher inherent stability than monohulls – there is far less healing due to side-imposed loads (such as wind forces) or load movement on-board (such as passenger movements to one side).  Catamaran hulls inherently provide compartmentalised buoyancy – damage one hull and the other will still provide reserve buoyancy. Normally each hull is divided into several watertight compartments which help increase damage-tolerance.
  • Wake Reduction: Wake size is of considerable importance due to shore-side wave disturbance when entering and leaving harbour or operating in river or estuarine environments.  The wake size of a catamaran hull is considerably reduced compared to a similar size monohull due to its long slender hulls.
  • Manoeuvrability: All larger catamarans (STEALTH technology works exclusively with catamarans in the 10m – 24m size range) have twin engine installations. With the engine spacing being further apart than on a monohull, controlled slow speed manoeuvring without bow thrusters is assured.