Military

RV Triton [Trimaran Research Vessel]

The UK MOD has been assessing the potential use of the trimaran hullform in future warship designs. All of the research is programmed to inform the decision on the hullform which will be used for the UK's Future Surface Combatant. The 1200 grt RV(Research Vessel) Triton was commissioned by the United Kingdom's Defence Research and Evaluation Agency (DERA) as a two-thirds scale frigate prototype. The 98m. long vessel is the world's biggest sea-going trimaran.

RV Triton was launched on 06 May 2000 and began an extensive set of sea-going trials at the begining of 2001 intended to asses the suitability of a trimaran to fulfil the Navy's requirement for Future Surface Combatant (FSC) frigate, due to enter service in 2013 to replace the Type 23. The purpose of the trials is to asses the sea-keeping performance and structural design of the traimaran compared to conventional monohull design. The use of the triamaran design for a warship is a radical departue from standard naval architecture and the trials programme is being watched closely by other navies.

There are numerous advantages of a trimaran hullform over conventional mono-hulls: reduced costs, reduced signature, significantly less drag leading to increasing speed, increased length giving greater stability, and more area for the upper deck which could be used for the flight deck and hangars for helicopters and extra armament. It is possible that the wide upper deck will lead to the provision of a second hangar which could be used for other service helicopters such as the Apache for land attack, support or relief operations.

The side hulls can also be utilised for configuring a multiline towed array sonar. A reduction in heat signature could be gained be exhausting between the side hulls rather than conventional main structure funneling. Increases in size and to some degree location of the superstructure can be easily accomodated without great affect to the ships stability. The required stability can be obtained by adjusting the size and distance from the main hull of the side hulls with little impact on drag and weight.

The initial work on trimaran warships was carried out at the University College in London where the UK MOD sponsors a department which studies warship design. In the early 90s as part of their MSc course students were given the task of designing various trimaran warships. The results of this work were so encouraging that the Royal Navy sponsors decided to fund research work at the Defence Evaluation Reasearch Agency to confirm the advantages promised by the hullform and also to understand the constraints imposed on the use of the hullform.

This work was started in 1994 and initially concentrated on the hydrodynamic aspects of the hull design and was carried out by running small-scale models of typically eight metres length in the tanks at DERA Haslar. The research was successful and the key parameters of main hull length to beam ratios, side hull length and position together with the lines were identified. As this was progressing computer design tools were developed which predicted the resistance, propulsion, seakeeping and manoeuvring characteristics of the trimaran warship.

Once the hydrodynamic design was set, DERA together with the UK MOD Procurement Executive investigated the structural design requirements. This was based on the development of load prediction computer codes in a series of numerical models which have been used to calculate the plate thickness, frame spacing and stresses which will be imposed on the ship by the onerous requirement to operate warships in the most strenuous of sea conditions. The final area of research covers survivability where any peculiarities of using a long slender hullform are being investigated through the use of scale model experiments and the development of computer based numerical models.

The results of the research have been most encouraging and to date nothing has been identified which negates any of the perceived advantages. However it is one thing to validate at small scale and then to have the confidence to build a fleet of trimaran warships. To fill this gap DERA has committed itself to fund and build an ocean going Trimaran Demonstrator - RV TRITON. During its first two years of life the ship will be used to validate the research results and resolve any risks associated with the hullform.

In September 1997, a memorandum of understanding (MOU) was signed by the United States and the United Kingdom concerning the Trimaran Demonstrator Project. The U.S. Navy and the U.K. Ministry of Defense jointly selected the US Navy's Carderock Division to have the primary responsibility for the design, construction, assembly, programming, test, installation, and operation of the Trials Instrumentation System (TIS) through the critical first six months of the R/V Triton's trials program. TIS was designed, constructed and installed by the Carderock Division aboard R/V Triton to fulfill this requirement. The TIS is designed specifically to meet the unique requirements of the Trimaran vessel. The function of TIS is to acquire, archive, display, and present the data generated from Triton's structural and seakeeping trials. The high-speed sampling and accuracy of the system ensure that the trials officers are obtaining the vital information that they require to perform a comprehensive evaluation of the Trimaran hull form.

RV TRITON itself is being constructed by Vosper Thornycroft, one of the UK's leading warship builders . The ship is some 90 meters at the waterline. This is considered the minimum necessary to provide results, which can be accurately scaled up to full scale to allow the final development and validation of the hydrodynamic, structural and survivability numerical computer models. The ship will be able to achieve a speed of 20 knots and has the endurance to cross the Atlantic Ocean without refuelling.

The contract was placed with Vosper Thornycroft in July of 1998 against a very aggressive design and build programme. The ship was launched in May 2000 with acceptance in September of the same year when the ship started the Future Surface Combatant risk reduction trials. These trials were conducted jointly with the USA who also wishes to understand the performance of the trimaran hullform.

On completion of the first two years of trials the ship will be available for hire as a general purpose trials facility for the testing and evaluation of either military or commercial equipment. A number of potential customers have been identified with the first being the US all electric ship project who wish to test some of their Integrated Power System modules in 2001. The ship itself makes a very able trials platform with its large after deck, which in addition to being able to handle a helicopter can also accommodate the fitting of eight containers with trials equipment. Within the ship there are a large number of empty compartments, which can easily be adapted to satisfy customer's requirements.

RV TRITON is manned by a commercial crew which will be contracted by DERA. It will be operated under the security umbrella of the UK MOD and will be a dedicated trials facility for the testing and proving of diverse weapon systems and equipments. It will have good speed and range characteristics with great flexibility to satisfy the needs of most hirers.