SPEED LOSS AND OPERATIONAL LIMITS OF HIGH-SPEED MARINE VEHICLES

In this paper the theoretical background for the computation of speed loss of high-speed catamarans and surface effect ships (SES) is described. The potential flow part of the problem is analysed by a simplified method that neglects hydrodynamic interaction between the hulls and accounts for the divergent wave systems generated by the hulls, as well as transom stern effects. The potential flow method has been validated by comparing with experimental data for steady wave elevation: wave resistance, added mass and damping coefficients, heave, pitch, vertical accelerations and added resistance in waves. Analytical formulation is used for wave resistance due to the cushion pressure and empirical formulae are used for the propulsion and the viscous resistance. The effect of increased air cushion leakage in waves, and subsequent sinkage and increased resistance is an important part of the method. Examples on speed predictions with 40m and 70m long catamarans and SES with water-jet propulsion are given. It is demonstrated that flush water-jet inlets on SES may be easily exposed to free air in relatively small sea states. It is shown that this problem can be reduced by using scoop inlets. The consequence of this is about a 10% higher shaft power. Operational limits based on comfort, system performance of propulsion and engine system are presented.

• Supplemental Notes:
  • IMAS 91, Intl Conf High Speed Marine Transportation; Sydney, Australia, 11-13 Nov 1991. Organised & Sponsored by Inst Marine Engrs. Pprs. Publ by Marine Management (Holdings) Ltd. Ppr 2, p 13 [9 p, 13 ref, 8 tab, 7 fig]
• Authors:
  • Faltinsen, O M
  • Holden, K O
  • Minsaas, K J
• Publication Date: 1991

Language

• English

Subject/Index Terms

• TRT Terms: Catamarans
• Uncontrolled Terms: High speed vessels
• Old TRIS Terms: Added resistance in waves; Speed loss
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00703561
• Record Type: Publication
• Source Agency: British Maritime Technology
• Files: TRIS
• Created Date: Aug 14 1995 12:00AM