Sea Defence

We are specialists in the field of naval power conversion and distribution, with equipment installed on virtually all of the Royal Navy’s submarine and surface fleet.

We have a strong export business and our equipment is deployed on many foreign Navies, including Australia, Malaysia, Oman, Spain, Turkey and Japan.

Our latest designs support a number of current European warship programmes including the S-80 submarines being built in Spain and the DCN’s Scorpene Class submarines.

In the normal course of events electrical supply is 115V AC or 440V 3phase generated internally and distributed throughout the vessel. This will support basic functions such as entertainment and domestic lighting through to Command and Control and weapons systems. A recurring theme in our equipment is support of electrical power in emergencies (such as the loss of main ship’s power) and the need to convert that original AC supply either to a higher frequency or to DC. Below are some examples that illustrate the broad range of specifications and applications.

Military Grade Uninterruptible Power Supplies (UPS)

Instant battery support for critical functions if main power is lost. Emergency power cuts in with no interruption and is available typically for up to 30 minutes. We supply equipment up to 60kVA for the Type 45 and QE Class Aircraft Carriers.

Static Frequency Converters (SFC)

Ships supply is 60Hz but up to 400Hz is required for sophisticated electronics like radar, gyros and weapons systems. We provide this conversion with a wide range of equipment up to 40kVA.

Transformer Rectifier Units (TRU)

DC power is required on board for many applications – machinery, fire doors, emergency communications. We convert ship’s supply to 28V DC for these purposes.

DC Distribution Systems with battery support

Often the rectification of AC to DC is far from being all that is required. Our support theme is reinforced with the need for such systems backed-up by batteries for emergencies. In addition we meet the need to distribute the power once rectified to a variety of facilities. The battery supported rectifier can incorporate what is in effect a mini switchboard for this purpose.

Equipment of this sort can be found on T45 as well as on Spanish Frigates and the new Australian Destroyers.

Helicopter Starting Systems (Heli_Start)

Like commercial aircraft, helicopters need ground assistance to start. This takes the form of 28V DC power up to 1800 amps.

Our Helicopter Starting Rectifiers are in service worldwide from New Zealand and Australia through Spain and Norway to virtually all helicopter carrying vessels in the Royal Navy. As well as the rectifier we supply a 40kVA Frequency Converter together with cabling and a variety of flight deck controls making a complete system for the starting and servicing of modern helicopters.

Submarine and Surface Ships Battery Charging Systems

If emergency power can be essential in supporting critical functions on a surface ship, it clearly has even greater importance on a submarine.

We have designed and supplied a combination of battery packages with associated chargers for submarines that supply emergency power to lighting and communications in the event of a loss of main power.

Currently these are deployed on Scorpene submarines and will shortly go into service in the new Spanish

S-80 class

For surface ships we have designed and supplied a range of valve-regulated lead acid battery boxes which affords a secure means of housing batteries which are used to back up the ship’s main and other supplies.

Support Equipment

In addition to these main systems Gresham manufactures a wide range of individual support equipment including:

  • Motor Starters
  • Automatic Changeover Switches (ACOS)
  • Through bulkhead Filter Boxes
  • UPS
  • Navigation Light Display and Control Panels
  • Distribution Panels
  • Weapons Panels
  • Ship to Shore Supply Boxes

Product Data Sheets