Download - BMT Catamaran Development

High Speed Catamaran Hull Development

• BMT have a large range of high speed monohull and catamaran designs

• In order to meet client requirements for good levels of comfort in rough water conditions, the company has developed new hybrid catamaran / SWATH (Small Waterplane Area Twin Hull) designs that offer significant improvement in vessel motions in higher sea states.

• Hull development was initiated by extensive work undertaken for USN on Seafighter project


Conventional High Speed Catamaran

• Low power requirement

• Moderate seakeeping capability

• Can be susceptible to uncomfortable pitch, roll and couple pitch and roll motions

SWATH

• Excellent Seakeeping Capability achieved by small waterplane area that reduces response of vessel to wave motions

• High power requirement

• Limited speed capability


MODCAT – Hybrid Semi-SWATH Catamaran Design Developed for USN to offer improverd motions in rough sea states developed by BMT Nigel Gee.

• Motions (~50% reduction)

• Powering – small power increase in calm water

• Power saving in rough water / Reduced speed loss in waves


• New eXtreme Semi-Swath (XSS) hull form design combines the benefits of Swath hull forms and catamarans

• Very good motions in rough sea conditions through SWATH type low waterplane area hull form in conjunction with high speed Ride Control System (RCS) using T-Foil and interceptor.

• Higher power than Modcat hull form but offering outstanding motions for reduced seasickness / increased passenger comfort

• Easy maintenance of main engines and waterjet propulsion

High Speed Craft - What Goes Where ?• The following looks at the performance benefits of different catamaran hull form

designs for high speed operation.

MODCAT (Semi-SWATH Catamaran)

• Slight increase in powering over catamaran

• Improved seakeeping

• Good for high speed ops on rougher routes

XSS (extreme Semi-SWATH catamaran)

• Higher fuel use / more limitation in speed over cat’

• Exceptional seakeeping

• Good for med’ to high speed ops on rough routes

Catamaran

• Good efficiency/ fuel use

• Good seakeeping

• Good for high speed ops on reasonably sheltered routes