This week’s video comes from Portsmouth where divers are helping to prepare Portsmouth Harbour for the return of HMS Queen Elizabeth
HMS Queen Elizabeth is coming home for Christmas but will need a little guidance into Portsmouth Harbour before her crew disembark.
To this end, 15 navigational aids mark the deep-water channel created for the aircraft carrier to manoeuvre safely.
Regular maintenance keeps the lights on top of the navigational aids shining brightly whenever HMS Queen Elizabeth enters or leaves the harbour and divers from BAE Systems have been tasked with the job.
More used to working up to 50m below water, seven members of the 14-strong diving team have qualified as climbers so they can scale the towers that are up to 30m tall and can sway by up to a metre.
“The team check the condition of the solar panels and batteries, ensuring they’re clean, free from guano and salt build up, and that the battery terminals are operating effectively,” said diving and maritime co-ordinator Jim Lynch. “We carry out planned maintenance on a six-monthly basis as well as regular checks to ensure they’re fully operational.”
This is a marked change to the divers’ normal routine of inspecting and maintaining almost five miles of sea walls around the historic naval base, including jetties, quay walls and berthing facilities as well as centuries-old culvert systems and service tunnels.
Lights on the navigational aids shine red, white and green to clearly show when the carrier is on the right heading, particularly entering and leaving the centuries-old narrow harbour entrance.
“The navigable channel is just 100m wide and, as the beam of the ship is 48m wide, these lights are absolutely critical to the carrier’s safe passage both into and out of the harbour,” said pilot Tony Bannister who, along with Captain Nick Cooke-Priest, will keep the carrier on course.
Radio-operated from Semaphore Tower in the naval base, the lights are switched on as soon as it’s confirmed that the carrier will be entering or leaving the harbour. The rest of the time they flash at low level to avoid other vessels colliding with them.
CLICK FOR A CANDID INSIGHT ON WHAT AWAITS HMS QUEEN ELIZABETH WHEN SHE RETURN HOME
It’s hard to believe that in the days of radar, lydar and GPS that these state of the art ships require lights on posts to navigate!
Well, I’d personally rather have some light beacons than have to rely on GPS (which could switched off anytime the US feels like it). That’s an aweful lot of ship to put through a narrow channel, and failure would be extreamly embarrassing, not to mention expensive!
Reminds me of a well known radio conversation that starts : “Left hand down a bit . . .”
A similar system is already in use in many airports all over the world for guidance in docking aircraft to passenger terminals. The system is highly accurate to within a very few centimetres on a straight line. The big advantage is that it is a visual system and can tell the captain instantaneously whether he is deviating from the correct line. I think similar systems are also used on aircraft carriers for landing aircraft.
Why use anything virtual? As these ‘leading lights’ are physically there, there is no margin of error, no electronic gremlins, no transponder or receiver issues and they work and have worked as systems all over the world for around half a century. The AIS AtoN units Mark L refers to do require maintaining, calibration and certification, albeit less than leading lights. I can guarantee they didn’t cost an awful lot, Levi was (I hope) poking fun out of BAe, but if you read the article, BAe didn’t actually build them, it was Sealite.
For the same reason, you still carry a compass, paper charts, dividers…and plot your position.