Ad hoc Marine Designs Ltd. has been engaged in many Windfarm projects in recent years, ranging from simple consultancy through to design of Windfarm monohulls and catamarans for very demanding duties.

In addition to the 24m FastSwath we have designed a range of SWATHs from 23m up to 50m for both Windfarm and Offshore Oil industry operations as workboats and crew boats. The exposure to rough seas for many hours can fatigue the crew and their technicians can be left feeling seasick and render them unfit for work; especially in the harsh and extreme weather conditions of the North Sea during the winter season. These SWATHs have been specifically designed to ensure all year round operability and safety for the crew. The ability to keep station and maintain service speed in ever increasing wave heights with benign motions is where a SWATH is without equal.


So, what is a SWATH, or ‘swath’ as is commonly termed? is an acronym for Small Waterplane Area Twin Hull; SWATH. It is a hull form that offers superior seakeeping over a conventional hull form such as a monohull or catamaran. It is essentially two (or sometimes four) thin struts that have 2 (or four) buoyant tubes below the surface. These thin struts have a much reduced waterplane area when compared to conventional vessels and this lower waterplane area decouples the motions of vessel from the waves. The seakindliness of a SWATH is not just slightly better than a monohull but several times better. Put another way, the motion of a SWATH will be similar to that of a monohull many times its displacement.

Below is the mid-range 32m SWATH.

Our range of SWATHs allows for safe and comfortable working conditions in Hs of 3.0m and without the requirement to slow down. Year round operations can be performed in safety and comfort. Existing WFSV catamaran vessels in the 15-25m range currently working in the Windfarm Sector are simply unable to cope with the sea states when going further offshore and also in winter seasons. More details can be found in the Windfarm section.

29m Typhoon Class Swath Crew Transfer Vessel for Windfarm Operations

The Typhoon Class of Swaths is suited for exposed and extreme sea conditions. This class of design comes in various sizes and duties from 15m workboats up to 50m Offshore operations and SAR patrols. The 29m Typhoon Class is an all HSC 2000 Code compliant Crew Transfer Vessel (CTV) for the windfarm industry. This variant has been optimised for crew transfers, carrying up to 24 technicians in superior comfort and safety in significant wave heights of up to 3.0m. This design allows for 24hour crew operations by providing sleeping accommodation along with a galley and mess. Thus extending the operational profile of the vessel.


33m SWATH Crew Boat for Offshore Oil Platform

Servicing and supplying crew to offshore oil platforms requires safe and comfortable operation year round in all sea states. The sea states experienced at these offshore oil platform locations are of the same magnitude as those at offshore windfarms, if not more. The remarkable seakeeping ability of the 33m SWATH shown ensures safe and comfortable operations. The vessel’s  motions are further reduced by the use of an active ride control system which results in year round operations in significant wave heights of 3.0m with service speeds up to 30 knots. Damping appendages are also integrated into the hull form to maintain these levels of comfort when stopped at station.

The general arrangement of the 33m shown is in the Oil Platform crew transfer configuration and is designed to satisfy ISO 2631 sickness criteria in all service conditions and meets LR or DNV’s R2 Crew Boat rules and the HSC 2000 code while transporting 60 passengers in safety and spacious comfort for both passengers and crew as well as 10 tonne of deck cargo. A brief specification of the vessels particulars is also provided.


The design is also available in 41m, which carries 148 passengers and 20 tonne of deck cargo at 29 knots service speed. All designs are tailored made for the exact wishes of the client. The Swath is no exception and can be design to suit your exact requirements.


26m WFSV Catamaran

With decades of experience in multihull designs in the Fast Ferry industry Ad Hoc Marine Designs has designed a range of Catamarans from 13m up to 26m designed to carry greater loads and be more versatile. Our most recent WFSV used our multihull expertise to satisfy a conflicting Statement of Requirements (SOR) namely: light, fast and able to carry heavy loads. This resulted in ‘Ashera’ operated by C.Truk with their unique modular wheelhouse.

For the more inshore and less weather dependant roles these small catamarans offer a wide range of solutions, a typical 26m WFSV is shown. This has been tailored to meet German Regulations. This and other catamaran designs by Ad Hoc can be designed to suit your exact requirements upon application.


47m Super Slim Catamaran passenger Ferry

The Ad Hoc Marine Designs 47m fast ferry taps into the experience of previous fast ferry designs operating worldwide ranging from 27m up to 85m. This fast ferry employs the experience of the much higher length displacement ratios to obtain faster speeds. The 47m passenger ferry carries 280 passengers at speeds ranging from 40 knots in diesel up to 48knots with a single gas turbine engine in each hull. It is designed to satisfy the existing HSC 2000 code and DNV’s HSLC Class rules. The styling has been done by world famous Dixon Yacht Designs.



Hydrographic Survey Vessel

A catamaran’s high initial stability coupled with a large working deck space provides the ideal solution for hydrographic survey work. The large deck area provides sufficient space for survey equipment, such as ROVs, deck cranes, RIBs. Additionally the accommodation on board is more spacious than on a monohull. For deep offshore work this design is well suited using a Swath Hull form owing to its superior seakeeping and station keeping abilities. Thus it becomes the ideal platform for long term operations.


Other Vessels:

An existing design can be considered as a starting position for discussions or simply a request for a repeat design of that shown. Details of the designs, General Arrangement and Specification, are available upon request. Ad Hoc Marine Designs has an unrivalled breadth and depth of design capability that is ideally suited for a wide range of vessels from concepts to full production. A selection of recent designs are shown:-


39m Cape Class Patrol Boat

The Ad Hoc Marine Designs 39m Cape Class is an aluminium patrol boat powered by twin waterjets, designed for Coastguard duties, Search and Rescue operations and Coastguard Law enforcement duties. The 39m Cape Class is capable of operations in the sea conditions up sea state 6. Propulsion and steering is effected through twin waterjet propulsion units, which also provide cruise and loiter capability and full manoeuvrability.

We have considerable experience in the design and production of aluminium vessels with water jet propulsion. The design of the 39m Cape Class draws on this experience of vessels operating with a wide variety of customers. The design includes a number of novel key features which further improve the vessel design and operational capability.

The 39m Cape Class is available in a wide variety of configurations, and depending upon the final engine choice, service speeds range from 26 to 35knots.

Cape Class Patrol Boat


58m Cape Class Patrol Boat

This 58m Cape Class Patrol Boat is designed for services speeds between 20 to 35knots in either steel or aluminium depending upon the engine selection and propulsion arrangement.  The 58m Cape Class patrol boat shown is configured for long range ocean patrol with 2 x 7.5m RIBs on the aft deck with a compliment of 25 officers and crew with room for up to 16 passengers as visitor on board. Additional facilities  include FiFi fire fighting capacity and a 20mm Canon on the fore deck for protection and deterrent. The 58m Cape Class patrol boat provides an exceptional platform for the diverse range of Para-military mission requirements within and beyond the EEZ.








17m Fast Combat Patrol Boat

This 17m patrol boat is an all aluminium high speed combat boat suitable for a variety of roles. Available in various engine and propulsion configurations; propeller, surface drives and waterjets, ranging in speeds from 30 to 50knots.  Key Features include: Fast yet robust alternative to traditional “Interceptor” type boats, Highly manoeuvrable at all speeds, Suited to high intensity patrol duties, Simple, reliable and robust machinery installation with in-built redundancy, Ability to tow other craft, Multiple heights & positions for boarding duties, Aft well for divers and recovery of items from the water, Quiet air-conditioned wheelhouse / cabin with good all round visibility, Prolonged loiter capability with optional centreline waterjet configuration.








45m Monohull Passenger Ferry

The Ad Hoc Marine Designs all aluminium 45m monohull passenger ferry is designed to carry up to 600 passengers at speeds up to 30knots. The 45m is designed to satisfy DNV’s HSLC rules and the HSC 2000 code.


For further details on these designs, and others, please contact Ad Hoc Marine Designs Ltd here.

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