THIS is the moment more than 128,000 tonnes of water was pumped out from one of Portsmouth Naval Base’s dry docks to make way for one of the navy’s frigates.
HMS St Albans is undergoing essential repair works following her nine-month deployment.
And to make life easier for her engineers the water surrounding the Portsmouth-based warship in one of the base’s dry docks has been removed.
To put this in perspective, the amount of fluid drained from the dock would be enough to fill about 1,068,333 bathtubs.
Deputy Marine Engineering Officer Lieutenant Peter Ainscow said: ‘Getting into dry dock is a lengthy process but it is essential to carry out essential underwater maintenance that otherwise would be expensive or impractical to be completed in the water by divers or in a habitat.
‘All ships incur wear and tear from deployments and HMS St Albans in particular has been operating at a high operational tempo which makes this sort of work necessary for her continued capability.’
All ships incur wear and tear from deployments and HMS St Albans in particular has been operating at a high operational tempo which makes this sort of work necessary for her continued capabilityLt Peter Ainscow
The Type 23 frigate was kept sitting in a central position using a laser alignment for the 11-hour operations to drain the site.
St Albans is being kept upright by a series of large wooden beams that brace the ship’s side against the dock walls, with cranes levering them into position.
The precise process of lining the ship up is vital as all the underwater equipment located on an antisubmarine frigate, including her sonar dome, only have 50cm clearance to the dock bottom once all the water has been drained.
Maintenance works will include repairs to her underwater fittings and works to her rudders, including painting them, to ensure they are preserved until the next planned maintenance period.
The frigate will be in the dry dock for several weeks before the water will be allowed back in and she will return to sea.
Dry Docks have been used since the 10th century to allow for maintenance, repair works and construction of ships.
Portsmouth Naval base also still has the oldest surviving dry dock commissioned by Henry VII in 1495.
This dock currently holds the world’s oldest commissioned warship, HMS Victory.