I thought IEP is of benefit for ships with many power hungry systems like lasers, railgun, EMALS, big ass AESA panels and so on, hence why Zumwalt is IEP since originally it was to have two railguns. What's the benefit of IEP for AWS ships?
CV-18 Fujian/003 CATOBAR carrier thread
- Thread starter Jeff Head
- Start date
Intrepid
Major
With IEP (Propulsion) you add one more power hungry electrical systems. So it is the second step.
That’s when compared to conventional steam propulsion carriers. I don’t expect any advantage in this regard when compared against a gas turbine driven ship like QE.
why do Most recent cruise ship have IEPS?
Intrepid
Major
The extreme agility of being able to do without tug assistance in every port. In other words: save costs, be less dependent on scheduling.
lcloo
Captain
Huge amount of electricity is need to be used in floating hotel operation - the lights, elevators, electronics, galleys, water treatment plant, cold rooms and freezers for raw food required to feed thousands of passengers and crew, laundry, air conditioning and heating etc, as well as propulsion. The electricity requirement of a cruise ship is large enough to power up a small town.
No, those are not the only significant benefits.
A major benefit is the ability to decouple prime movers from propellers. Thereby, you can eliminate the heavy gearboxes and clutches. You can run the prime movers at their most efficient speed. You can fully decouple the prime movers from the hull, significantly reducing the acoustic profile of the ship (also important for the comfort factor on cruise ships). You have very large freedom in where to place the prime movers: Queen Mary 2 has them just under the funnels, way above deck, thereby saving huge amounts of volume that would otherwise be consumed by ventilation stacks. You can have podded electric motor propulsors (or azipods), thereby eliminating long shaft lines and rudders. Azipods can be designed to be a more efficient propulsor than a conventional shaft and propeller (I've seen numbers of up to 18% more).
The other key point I see here is
If you have to replenish aviation fuel, you might as well replenish propulsion fuel at the same time.
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If a similar $8100 Million difference in lifecycle cost applies between Chinese nuclear versus conventional carriers, then it is clear that conventional carriers are vastly superior. Particularly since China doesn't already have a mature nuclear carrier design and replenishment ships are cheap.
The Royal Navy Tiger-class replenishment ships are only $180 Million to buy, and my guesstimate is that they have a lifecycle cost of about $540M.
So adding an additional replenishment ship is a far cheaper and more effective option, than in going for a nuclear-powered carrier.
And that logic is even stronger when operating within the 2nd Island Chain, which means Chinese CSGs don't have far to travel and are close to resupply ports.
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If you use the aviation fuel figures in the report, you end up with
JFK: 5days of aviation operations. Based on 1.8M gallons of aviation fuel @ 10000 litres per aircraft x 160 sorties per day
Nimitz: 10days of aviation operations. Based on 3.5M gallons of aviation fuel @ 10000 litres per aircraft x 160 sorties per day
So refueling every 3days is not an issue.
Nuclear carriers capable to cover bigger distances in shorter period of time.
It could be important during wartime operation, when they have to move fast to outrun the submarines/ ships.
Double the speed of a ship increase the fuel consumption eight fold.
It could be important during wartime operation, when they have to move fast to outrun the submarines/ ships.
Double the speed of a ship increase the fuel consumption eight fold.
There would be some benefits yes.
But nuclear carriers are limited by the speed and endurance of their accompanying escorts.
I don't see how it would be worth the additional cost for the Chinese Navy.
The top carrier speed is still limited by the amount of power transmitted through the propellers.
You size the propellors with the powerplant in any case, where nuclear or conventional.
True, but diesel fuel is cheap at 70cents per litre
The JFK carried 2.4M gallons of ship fuel. That would cost $8 Million, which is equivalent to just 3 LRASMs.
If it's wartime, the cost of that ship fuel is negligible when compared to the cost of ships, aircraft and missiles.
What matters is that a replenishment ship is always available to provide supplies.
That applies to a nuclear carrier as well.
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