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Current & Future Escorts - General Discussion

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Pongoglo
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Re: Current & Future Escorts - General Discussion

Postby Pongoglo » 06 Mar 2019, 10:47

Lord Jim wrote:Just out of interest, is there a reason we haven't tried to fit a Phalanx on top of the Hanger on the T-23 now that Sea Wolf has been replaced?


£££££££ !

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Re: Current & Future Escorts - General Discussion

Postby Aethulwulf » 06 Mar 2019, 10:55

Pongoglo wrote:
Lord Jim wrote:Just out of interest, is there a reason we haven't tried to fit a Phalanx on top of the Hanger on the T-23 now that Sea Wolf has been replaced?


£££££££ !
Finding space for fitting Phalanx operators consoles in the Ops room might be also be quite a challenge. Its already a bit snug...

https://www.facebook.com/ForcesTV/videos/165337294417043/

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Re: Current & Future Escorts - General Discussion

Postby ArmChairCivvy » 06 Mar 2019, 11:37

Waterjets coupled with gas turbine(s) are, for sure, used for sprint speeds.

There's also a new strand of thought arising - certainly not implemented on MEKO A200 as of today - which I referenced on Dec 27 last year:
ArmChairCivvy wrote:However RR has had access to this all electric demonstrator https://www.globalsecurity.org/military ... -081-s.jpg to try out a new type of water jet (all electric, minimising the internal noise and the waterjet itself designed to clearly beat propeller cavitation noise levels) where also flow noises, around the hull have been minimised: https://www.globalsecurity.org/military ... 6w-052.jpg


The big BUT is of course that the t-31 RFI specifically glosses over ASW rqrmnts, so difficult to see that any provision would be made in the design for including silent running/ drifting propulsion (e.g. for the space that would be taken up by it), to be taken up/ populated in later batches.

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Re: Current & Future Escorts - General Discussion

Postby shark bait » 06 Mar 2019, 12:09

Aethulwulf wrote:https://www.facebook.com/ForcesTV/videos/165337294417043/


Good little video. I had no idea they still kept the old analog consoles, it's all suppose to be integrated these days, any ideas why they keep them?
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Re: Current & Future Escorts - General Discussion

Postby donald_of_tokyo » 06 Mar 2019, 13:35

Aethulwulf wrote:Finding space for fitting Phalanx operators consoles in the Ops room might be also be quite a challenge. Its already a bit snug...
https://www.facebook.com/ForcesTV/videos/165337294417043/
Nice video. By the way, I do not find big difficulty on locating one CIWS console there. They will find it, if they are needed.

The reason why T23mod do not carry CIWS, for me, looks like related to the very low position of CAMM data-link antenna. It shall better be located on higher place, at least as high as the SeaWolf Fire Control Radar, so that future addition of data-links, sensors, as well as CIWS can be possible.

But, it was kept as low as possible. I guess it is because of center of gravity issue. Adding 1 CIWS will be easy now, but the last T23ASW will be active for another 15 years, so there must be some marines, as well.

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Re: Current & Future Escorts - General Discussion

Postby NickC » 06 Mar 2019, 13:58

shark bait wrote:
NickC wrote:have abandoned water jet propulsion of their LCS class ships and changed to propellers.

Non of the littoral combat ships apply CODAG WARP propulsion. They only use water jet's which are inefficient at anything other than full speed.

Meko's CODAG WARP on the other hand has both jets and props to give good efficiency at high and low speeds respective.


My understanding of CODAG WARP is that waterjets give higher efficiency at high speeds, crossover point between waterjets and propellers probably in the region of 30-35knot range. Propeller efficiency declines very rapidly at these high speeds and the waterjet might deliver 10-15% more effective power. In CODAG WARP, the propellers will also be lighter loaded, so more efficient. 

That's why waterjets were used on USN LCS class ships which were 40 knot+ ships requiring massive power of two GTs, either LM2500 or MT30, with a max range of ~1,000nm at that speed.

Question becomes does ship require the added complication and cost of a waterjet for these high speeds with marginal gain in efficiency over CPP for the very limited time in use, USN Burkes spend only 2% of time at full power.

General impression from press reports is the South African Meko class has a history of breakdowns ?

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Re: Current & Future Escorts - General Discussion

Postby Ron5 » 06 Mar 2019, 17:47

shark bait wrote:
Lord Jim wrote:The idea of creating centres of excellence for different types of naval vessel, like Barrow for submarines, is looking like the only way ahead

You mean like the process that lead to BAE's TOBA?


He means like the process that every other major country in the world employs.

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Re: Current & Future Escorts - General Discussion

Postby Ron5 » 06 Mar 2019, 17:49

shark bait wrote:
Poiuytrewq wrote:The CODAG WARP setup does look interesting but not especially quiet?

It's likely to perform better than a direct drive diesel, gas turbines need to be perfectly balanced and tend to emit higher frequencies which don't transfer so well through water.

Wont be as good as a diesel electric hybrid where the noisy bits can be totally isolated from the hull.


Surface waterjets like this one are incredibly noisy and can be detected hundreds of miles away.

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Re: Current & Future Escorts - General Discussion

Postby Ron5 » 06 Mar 2019, 17:54

Aethulwulf wrote:I would be very surprised if the Meko A200 variant offered for the T31 retains any form of waterjet propulsion. In fact, even retaining a Gas Turbine would be an eye opener.

Given the T31's need to keep things simple, I would expect that the RN would be happy to accept a limit of 23 kt top speed using two diesel engines.


The price of the gas turbine installation would kill this idea pretty quick.

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Re: Current & Future Escorts - General Discussion

Postby Lord Jim » 06 Mar 2019, 17:56

Ron5 wrote:He means like the process that every other major country in the world employs.


Oh, well in that case yes, surely that should be a no brainer first step into getting our naval ship building back on track, increasing productivity and cost effectiveness and therefore benefitting the UK in the process.

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Re: Current & Future Escorts - General Discussion

Postby Ron5 » 06 Mar 2019, 17:56

ArmChairCivvy wrote:
Aethulwulf wrote:I would be very surprised if the Meko A200 variant offered for the T31 retains any form of waterjet propulsion


I take it that you take an affordability rather than benefits approach (in saying that)? Whole-of-life cost calculation might be surprising - and the benefits for upgrade-ability to an ASW role less so:

"MEKO A-200 features the revolutionary CODAG-WARP (Water jet and Refined Propellers) propulsion system: two CPP (Controllable Pitch Propeller) propeller shafts driven by cross-connectable diesel engines plus a centre-line gas turbine-driven water jet, combining the power of each drive in the water without the need of a combining gearbox. This arrangement allows for extremely quiet acoustic signatures, a high degree of propulsion redundancy and damage survivability. The propulsion arrangement also provides, in the diesel only mode, an extremely economic solution, whereby a single engine can drive both shafts for a ship speed of 18 knots/20.7 mph/33.3 km/h, meaning that the ship will spend most of its life on a single engine"


Ship is only quiet when the waterjet is turned off. Even then, being direct diesel drive, it will not be "extremely quiet" like the brochure says.

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Re: Current & Future Escorts - General Discussion

Postby Lord Jim » 06 Mar 2019, 17:59

Makes you wonder how effective the LCS based Frigate designs for the USN competition are going to be with their propulsion systems, unless they have changed them with the larger design.

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Re: Current & Future Escorts - General Discussion

Postby Ron5 » 06 Mar 2019, 18:04

ArmChairCivvy wrote:Waterjets coupled with gas turbine(s) are, for sure, used for sprint speeds.

There's also a new strand of thought arising - certainly not implemented on MEKO A200 as of today - which I referenced on Dec 27 last year:
ArmChairCivvy wrote:However RR has had access to this all electric demonstrator https://www.globalsecurity.org/military ... -081-s.jpg to try out a new type of water jet (all electric, minimising the internal noise and the waterjet itself designed to clearly beat propeller cavitation noise levels) where also flow noises, around the hull have been minimised: https://www.globalsecurity.org/military ... 6w-052.jpg


The big BUT is of course that the t-31 RFI specifically glosses over ASW rqrmnts, so difficult to see that any provision would be made in the design for including silent running/ drifting propulsion (e.g. for the space that would be taken up by it), to be taken up/ populated in later batches.


The cost of developing submerged waterjets into a production system would need more than the entire Type 31 development budget.

I thought the Type 31 RFI was pretty clear on ASW i.e. do what you can within the budget to allow for an ASW upgrade.

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Re: Current & Future Escorts - General Discussion

Postby ArmChairCivvy » 06 Mar 2019, 19:19

Ron5 wrote:The cost of developing submerged waterjets into a production system would need more than the entire Type 31 development budget.

I thought the Type 31 RFI was pretty clear on ASW i.e. do what you can within the budget to allow for an ASW upgrade.

I think you are right, so it is a rather big 'but'
- Rolls is at it... may be for the next class :) of ships. Or the next

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Re: Current & Future Escorts - General Discussion

Postby Ron5 » 06 Mar 2019, 23:27

ArmChairCivvy wrote:
Ron5 wrote:The cost of developing submerged waterjets into a production system would need more than the entire Type 31 development budget.

I thought the Type 31 RFI was pretty clear on ASW i.e. do what you can within the budget to allow for an ASW upgrade.

I think you are right, so it is a rather big 'but'
- Rolls is at it... may be for the next class :) of ships. Or the next


Not sure Bird Johnson or RR is still working on it. Been very quiet the past couple years. I've read a couple of papers on the topic and it was all past tense in terms of testing & results. Nothing about what was to come next. I fear this idea might be dead. It was a bit of a longshot to start with. Shame.

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Re: Current & Future Escorts - General Discussion

Postby shark bait » 07 Mar 2019, 07:56

Ron5 wrote:Surface waterjets like this one are incredibly noisy and can be detected hundreds of miles away.

Depending on the speed they may still out perform a traditional prop because they feature lots of ducting to condition the flow.

To put it simply a waterjet is likely to out perform a prop on efficiency and noise when operating at high speeds, but across the operational range that is used 90% of the time propellers are preferable.
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Re: Current & Future Escorts - General Discussion

Postby Tempest414 » 07 Mar 2019, 08:05

Cammell Laird chairman got it right when he said Type 31 has to work out of the box which means good solid ship building and well proven kit that is known to work fitted

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Re: Current & Future Escorts - General Discussion

Postby shark bait » 07 Mar 2019, 08:41

correct, and to be clear I'm not advocating the above for the T31, merely discussing the details because that's what nerdy engineers like me do!

The T31 needs to use a commercial diesel electric system, its modern, capable and affordable.
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Re: Current & Future Escorts - General Discussion

Postby NickC » 07 Mar 2019, 10:12

Lord Jim wrote:Makes you wonder how effective the LCS based Frigate designs for the USN competition are going to be with their propulsion systems, unless they have changed them with the larger design.


As mentioned previously they have dropped waterjets and using propellers and either going all diesel or diesel with GT. The LM Freedom design for frigate bears only a passing relationship as now 6,000+t ship whereas LCS had a naval achitectual displacement limit of 3,550t

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Re: Current & Future Escorts - General Discussion

Postby Lord Jim » 07 Mar 2019, 10:57

I knew they were much bigger but wanted confirmation on the propulsion change. Does make you think when the sales Reps for both companies state that there submission are an evolution of their respective LCS designs how much that is aimed at those who want to save money and also pushing the interpretation of being based on an existing hull design.

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Re: Current & Future Escorts - General Discussion

Postby ArmChairCivvy » 07 Mar 2019, 11:21

NickC wrote:now 6,000+t ship whereas LCS had a naval achitectual displacement limit of 3,550t


This is a good (fun) story as in the original Streetfighter Conceptual USN study the Swedish Visby was considered as one of the best alternatives for a forward-based littoral ship. Though the thinking then switched to the rqrmnt for not only ocean-crossing capable, but for a fast-intercept anywhere in the ocean in most weathers. Before that change stepped in, I believe Visby+ was in the frame (and Visby++ was the one that lost out to the Formidables in Singapore)

"The Visby Plus has been programmed to reduce production costs, even as it will have full stealth technology. Its design takes a modular approach to simplify customization, including weight and volume reserved for future modifications.

The initial Visby Plus carbon-fibre cored composite model is 88 meters LOA, with 1 500 tonnes displacement. Its prime functions will be anti-submarine warfare, surface attack, air defence, training, and patrol. According to preliminary calculations, when compared to a conventional propeller-driven steel vessel, with an aluminium superstructure, funnel exhausts, and non-stealth weapons and sensors, the new design will have the following considerable gains:

A lower profile for a reduced visual signature
A lighter, more shock-resistant structure
A lower displacement and draft, requiring less engine power
Reduced fuel consumption, hull maintenance, and operating costs
Lower hydro-acoustic, magnetic, infrared, and radar signatures.

The new corvette will have berths for 71 crew, a helipad and hangar, two universal cranes and two ship’s boats. The propulsion will be four diesel engines of about 7 400 kW driving four waterjets. The engine room will be set aft, to leave appreciable volume amidships for operations."

Going back to the quote, every step seems to double the displacement. Our "to be forward based" ship is also quite big
- is it for future roles (flexibility of config/ refit)?
- endurance as an OPV+
- or, close to the above point, is it that it has to be "globally deployable" as well as being - some of them at any given time - forward based... and is that actually a bad compromise?

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Re: Current & Future Escorts - General Discussion

Postby Tempest414 » 07 Mar 2019, 12:14

Lord Jim wrote:I knew they were much bigger but wanted confirmation on the propulsion change. Does make you think when the sales Reps for both companies state that there submission are an evolution of their respective LCS designs how much that is aimed at those who want to save money and also pushing the interpretation of being based on an existing hull design.


We have seen this before in the US Navy in the form of the F-18 Hornet to Super Hornet they look same enough but in fact are complete different

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Re: Current & Future Escorts - General Discussion

Postby ArmChairCivvy » 07 Mar 2019, 12:37

Tempest414 wrote: seen this before in the US Navy in the form of the F-18 Hornet to Super Hornet


Yep, from bomb truck to do-it-all-in one
- because of budgetary pressure: to preserve the number of platforms, to be able to ramp up later
- therefore, do accept "lower, but flexible spec"
rather than insist going on with bleeding edge designs, which
- because of (inevitable cost overruns)
- will end up so few in number
- that there won't be enough, for them to show up where they will be needed
- not to mention that "ramping down" the manpower - thanks to these "super"platforms having to be paid for - there will be no chance of ramping up again, within any relevant time frame (relevant to an emerging/ changed threat picture)

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Re: Current & Future Escorts - General Discussion

Postby NickC » 07 Mar 2019, 14:53

Lord Jim wrote:I knew they were much bigger but wanted confirmation on the propulsion change. Does make you think when the sales Reps for both companies state that there submission are an evolution of their respective LCS designs how much that is aimed at those who want to save money and also pushing the interpretation of being based on an existing hull design.


The LM Freedom frigate as said moving from waterjets to twin propeller design with port and starboard engine rooms to be in staggered configuration length wise, running into a single shaft into a screw on either side to be fully independent. Required to meet USN survivability specs so if the ship takes damage in one area, the other engine room should be able to stay online to drive the ship.

LM is looking at combined diesel and gas systems, or combined diesel and diesels for FFG(X), speed reduced from 40+knots for LCS to 26 knots threshold/28 knots objective for frigate. LM said USN receptive but mixed on the idea of a straight diesel propulsion system, the trade-off for gas turbines is less fuel efficiency, which impacts range.

The LCS Freedom has a semi-planning hull for high speeds, but understand at ~ 14 to 26 knots incurs very high resistance compared to a standard displacement hull, would guess frigate will be standard displacement hull of 6,000+t as quoted, if so the any resemblance to LCS will be in name only.

The Austal Independence frigate design appears to be with only with minor modifications from LCS hull, lengthened from 418' to 456', 38'/ ten frames, so as to fit 32 VLS cells now spec'd, previously 16. The propulsion system is totally new as no waterjets or GTs, CPPs with CODAD. Austal will be conducting tank tests of the new hull form to validate its characteristics and performance, mentioned they may further tweak the design and might be able to shorten the hull length back.

It looks like the Austal will be by far the lowest displacement contender for the USN frigate contract, the LCS Independence Naval architectural displacement limit is 3,188t, the frigate is not that much larger, the FREMM displacement quoted as 6,900t and with USN specs will be 7,000t ship, BIW/Navantia F100/Hobart 7,000t and Ingalls have released no info on their frigate design based on the USCG NSC 4,600t.

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Re: Current & Future Escorts - General Discussion

Postby ArmChairCivvy » 07 Mar 2019, 16:48

In the USN case it
NickC wrote: looks like the Austal will be by far the lowest displacement contender for the USN frigate contract, the LCS Independence Naval architectural displacement limit is 3,188t, the frigate is not that much larger, the FREMM displacement quoted as 6,900t and with USN specs will be 7,000t ship, BIW/Navantia F100/Hobart 7,000t and Ingalls have released no info on their frigate design based on the USCG NSC 4,600t.

which is 'go big, or go home'.

I posed the question whether that is, or should be our case, too?


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