Now consider these new Type 45 destroyers are supposed to be the central force for our modern Royal Navy, but they rely on twin propeller shafts, a system used by the RMS Titanic, over a 100 years ago!
The say a Camel is a Horse put together by committee, and clearly the original design and specification was repeated messed around by the then Government to ensure Rolls Royce could keep its 1,000 work force in employment and produced a power train that was under developed at the time and is seemingly is too weak for the robust job required. Engage the back up systems and nothing happens. There isn't sufficient redundancy built in.
It was also supposed to deliver operational speeds of 30 knots! Now we know senior politicians and ministers read this blog, so for what it is worth, this might be a way of not only saving face but swiftly ensuring the long term future of these Type 45 Destroyers.
Simply the reliance on just two electric engines to drive the two shaft driven propellers, is very old hat. We need lots of engines!
The original call was for American LM 2500 Gas turbines to be used - as used by many countries - but we opted for the mega expensive but politically canny Rolls Royce option, which was not really fully designed and proven for this type of hostile operation.
So our suggestion is that instead of just being reliant on the existing shaft driven twin propellers, the addition of 3 externally mounted fully self contained ABB azipods, would not only provide propulsion, but also as each azipod contains it own electric motor to drive the individual steerable propellers, there is immediately built in redundancy and best of all ABB azipods are externally bolted on swap out units. Simply all that is required is an electric power supply, the motor and propeller are integral to each individual azipod.
I've been on board the 'Independence of the Seas' when three days into the cruise, one of the azipods developed a fault, and had to be taken out of service. The ship carried on using the remaining azipods and completed the cruise, slightly slower, distance made up at night so no one really noticed.
A post-cruise three day dry dock was all that was needed to swap out the faulty unit and bolt on the replacement ABB azipod.
Rather than re-invent the wheel, here is the original press release - complete with flowery PR type language - relating to a later vessel the Oasis of the Seas:
ABB Azipod units propel the world’s largest cruise ship across the Atlantic.
Royal Caribbean’s newest vessel crossed the Atlantic last week and was delivered to its owners in Miami, in time for its first commercial Caribbean cruise in December. Weighing in at around 100,000 tons and costing an estimated $1.2 billion, the enormous ship posed a new set of challenges for its designers.
Operating a ship of this size in busy ports and out at sea, where weather conditions are not always favourable, requires a special solution. ABB delivered a tailor-made electrical propulsion system, comprising three 20-megawatt (MW) Azipod propulsion units, to provide the additional reliability and manoeuvrability required. But ABB delivered more than just the propulsion units.
“We provided the generators, main switchboards, frequency converters, transformers and remote control units for the ship,” said Jarmo Orava, ABB’s Marine project manager for Oasis of the Seas. “Our ‘scope of supply’ document for the vessel ran to more than 70 pages.”
Installing the propulsion units was perhaps the greatest technical challenge for ABB – because of the additional Azipod unit, an entirely new software system had to be put in place – but the most time-consuming job was installing the electric cabling. There are 5,000 km of electric cables and about 100,000 electric points on the vessel.
Originally developed in Finland by ABB in collaboration with Kvaerner Masas-Yards dockyards, Azipods have now been installed in 81 vessels, from cruise liners to icebreakers and drilling rigs. They have accumulated almost 5 million hours of operation. ABB is the world’s leading supplier of power and propulsion systems for the marine industry.
JULIAN BRAY +44(0)1733 345581, Aviation Expert, Journalist, Broadcaster, Aviation Security & Airline Operations Expert, Travel / Maritime & Cruise Industry, NUJ, EQUITY, LIVE ISDN LINK, Broadcast ISDN COOBE ++44 (0)1733 345020 (ALL CODECS) e&oe Old faithful NOKIA: 07944 217476 iPhone 0743 530 3145 www.aviationcomment.com Contrib. Account #104764 53 FEED: http://feeds.feedburner.com/BraysDuckhouseBlog