Rotating Arm
Parent Body: Defence Evaluation and Research Agency (DERA), Haslar, Gosport, Hampshire, PO12 2AG

Principal Functions
The rotating arm duplicates all of the steady state testing capabilities of a towing tank, except that the steady state motion of a model ship or submarine is on a circular path rather than a straight line path.

General Details
The rotating arm is situated in the manoeuvring tank at Haslar. It is 27.5m long and can be rotated at angular speeds of up to 0.6rad/sec. Models of ships, submarines and submersibles can be suspended beneath it in water of 5.5m depth. The models can be rotated at any radius and speed, with superimposed drift/yaw and pitch angles if required. All six components of force and moment acting on the vessel can be measured.

Special Features
All facilities at DERA Haslar are equipped with minicomputer data acquisition systems. They are supported by drawing offices, workshops, instrumentation laboratories and operations staff. Models for testing in the facilities can therefore be designed, manufactured, instrumented and controlled for clients, or clients can supply their own models. DERA also has access to other testing facilities, including a 30m deep quarry, which are equipped so that the same models can be operated in them.

Future Plans
A motorised model carriage, with its motion synchronised to the rotation of the arm, is under consideration. This will enable models to be tested on circular paths with radii greater than the radius of the arm.

Availability
The facility is available to other bodies in both the private and public sector. There are no restrictions on the type of body that can apply to use the facility. Variable new facility bookings are fitted into the existing programme by agreement with the client. Time on the facility is allocated in accordance with an ‘experiment contract’ agreed between DERA and the client.

Charging Basis
Charging rates are subject to negotiation and are agreed as part of the ‘experiment’ contract. There is the possibility of negotiating an exchange agreement. The minimum hire period for the facility is half a day.

Site Access
The site has ready access for vehicles and local accommodation is available for the hirer’s staff.

Contact Information
Ian Grant, Commercial Manager
Centre for Marine Technology
Building 58, Room 114A
DERA Haslar
Haslar Road
Gosport
Hants, PO12 2AG
Telephone: 023 9233 5130      Fax: 023 9233 5012
E-mail:  idgrant@dera.gov.uk