Since the WARP (central waterjet) is not a good option for an Arctic vessel, I would add two electric motors (about 2.0 to 2.5 MW each) for electric propulsion up to 15-16 knots. Obviously, the diesel generators should be dimensioned (rated) accordingly.
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A100 is CODAD MW PDE. So no need for the WARP if one were to go that particular engineering route.
But there is also something to be said for having a simple ship, that isn't overly complicated.
Oldgateboatdriver
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That! 100%
Especially if you want to build something where production can be ramped up quickly in times of need.
Fully agree, I don't consider electric propulsion as complex. Both the MCDVs and AOPS have It.
The only issue is how to reach 25 knots.
a) with two or four diesel engines (added)
b) with one gas turbine (could be the LM2500+)
c) a combined (but more complex) solution like two diesels (for Cruise at about 20 knots), combined diesel-electric and diesel, plus the gas turbine.
Regarding WARP, I was rather thinking of the new Meko
en.wikipedia.org
The only issue is how to reach 25 knots.
a) with two or four diesel engines (added)
b) with one gas turbine (could be the LM2500+)
c) a combined (but more complex) solution like two diesels (for Cruise at about 20 knots), combined diesel-electric and diesel, plus the gas turbine.
Regarding WARP, I was rather thinking of the new Meko
MEKO A-200 DEU-class frigate - Wikipedia
Oldgateboatdriver
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Electric propulsion is only complex in the number of things that you have to watch for compared to straight diesels with shafts and Variable pitch propellers, but from a design point of view, I agree that it is not complex.
This said, the Absalon class and the Brits type 31 are four diesel to two shafts with VP. Simple, straightforward, redundant and giving you 25 + knots.
This said, the Absalon class and the Brits type 31 are four diesel to two shafts with VP. Simple, straightforward, redundant and giving you 25 + knots.
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This is a tour of the Iver Huitfeldt class engine room, in the engine room, by the Danish Captain responsible for the design.
His comments about cost containment were interesting.
Civilian yards with civilian standards and methods where possible and military where necessary.
Weapons and sensors reclaimed from other vessels using the STANFLEX principles.
The more interesting point was that the Danish Government (Logistics Organization or the Navy itself) took on the Prime role as Integrator.
On the plus side money was saved.
On the minus side those three ships have been de-rated from their Air Defence roles to Long Range Patrol Vessels. This is in large part due to software integration issues apparently.
But back on the plus side, for 325 MUSD (2010 dollars) each, the Danish Navy has three heavily armed Patrol Vessels in its fleet joining their two older siblings, the Absalons. The Absalons have gone the other way. They have gone from armed ferries to ASW platforms.
....
Couple of interesting observations.
Absalon had a high mission bay under the flight deck that raised the height of the flight deck, hangar and missile deck.
The Huitfeldts scavenged that mission bay for space which they used to make the engine rooms more friendly. They still managed to lower the superstructure height.
Power
Runs on 1, 2 or 4 diesels.
1 diesel gets you 18 knots and 9600 NM.
2 diesels get you 25 knots
4 diesels get you 29 knots
PS - The Absalons with the same hull form and displacement only have 2 diesels. One ran on one diesel on local ops in the Baltic for a while because it damaged its gearing which had to be removed, repaired on shore and reinstalled some months later.
Most cruising is at 12 to 14 knots.
4 diesels on line in 1 to 2 minutes.
Power packs (cylinders) can be pulled and replaced at sea with the engines running using overhead cranes and monorails.
The engine room is airconditioned.
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These two pages on discussion on design of the Huitfeldt and the Absalon might also be informative.
KevinB
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Why?
Oldgateboatdriver
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Because if you suck ice chunks or ice slush in the jet intake, it breaks the impellers or gums up the work and you stall. For a good example: Ask anyone who has had to clear slushy snow, almost water saturated snow, from their driveway with a snow blower.
Because ice may block the inlet of the duct and also the propeller inside the duct.
Additionally electric propulsion is preferred in ice because electric protections would trip if the propeller gets blocked. A diesel engine may get damaged in that case.
Both of them are way above 5,000 tonnes. French FDI also features four diesels and still above 4500.
Mogamis use a gas turbine, and within Mekos some use four diesels and some two diesels plus a GT.
IMHO electric drives are a no-brainer for a PC6/7. The dilemma, I would say, is mainly decide between four diesel engines or one GT to reach 25/26 kts.
DEs are more simple, less maintenance, much cheaper through their life-time. On the other hand GT requires less space and adds much less weight to the ship.
