Type 31 Frigate (Inspiration Class) [News Only]

[abc123]

I'm generally against classical mythology names for the RN ships.

[Tempest414]

I have to say I would like a F-class with

Faithful - Fearless - Firedrake - foresight - Fortitude

Batch 2

Foxhound - Fury - Favourite

[Repulse]

How about something more Global. Tribal and Colony class, maybe a Territory class:

Jersey, Guernsey, Gibraltar, Bermuda, Montserrat, Falklands, Ascension and Pitcairn.

[Caribbean]

What? No HMS Cayman?

[Repulse]

What? No HMS Cayman?

Perhaps swap out Jersey and Guernsey; depends on what we need to define as “Global” now to be a Global Navy

[Clive F]

I reckon it will be about the same time as the defence review that they name them. Bit of Navy PR.

[Ron5]

What? No HMS Cayman?

Perhaps swap out Jersey and Guernsey; depends on what we need to define as “Global” now to be a Global Navy

I thought you had them in to piss off the French.

[Caribbean]

The French also seem to have their knickers in a twist over the Cayman Islands as well

[RichardIC]

NickC wrote:
The recent Babcock announcement of contract awards signals that they are diverging from the Iver Huitfeldt propulsion spec, IH class features 4 x MTU 20V Series 8000 M70 (M71) @ 8,200 kW each (100% MCR), 32,800 kW, and four Caterpillar DG's, two 3512B gensets rated to 1,360 eKw 60 Hz @ 1,800 rpm and two 3508B gensets rated to 910 eKw 60 Hz @ 1,800 rpm, whereas T31 MTU order for is for both MTU MDE's and DG's.

No mention made in Babcock PR of MTU engine series chosen, the premium 8000 series, V20 @ 49.6t each, as used in the IH class, or the cheaper 1163 series V20 @ 25t each as used by the USCG Legend class NSC fitted with two 7,400 kW 20V 1163 and a history of numerous cracked cylinder heads even with the re-designed head and problems in operating in high water temperatures forcing ship to reduce speed, shades of T45, whether problems ever sorted don't know.


Why are we looking for conspiracies As Babcock have already said, and is only logical, they have reviewed the Iver Huitfelt equipment and updated them to the latest spec. i.e The MTU 20V 8000 M71 is the current updated model.

I would be highly surprised if they went with the MTU 1163 as it is a completely different engine and would require revised mounts and changes to props/gearboxes as it runs at higher revs. It would be a costly redesign. It would also be 40% down on power compared to MTU 8000 installation.

Regarding the change from CAT to MTU DGs these are a lot more interchangeable and it probably makes more sense from a support perspective to use the same Manufacturer for Main and Aux power and also have commonality with T23/26/45 etc.

I can't claim to know anything about diesel engines. But this says:

The installed power plant will have the capacity to produce a maximum power of over 32,000 kW.

https://www.marinelog.com/technology/u- ... r-systems/

[Ron5]

Thanks Richard for posting the article. The last paragraph was particularly interesting:

"The propulsion system will ensure a low underwater-radiated noise (URN) signature and will comply with IMO Tier III regulations. It will also enable each vessel to attain a maximum speed of more than 25 knots."

[Jensy]

Thanks Richard for posting the article. The last paragraph was particularly interesting:

"The propulsion system will ensure a low underwater-radiated noise (URN) signature and will comply with IMO Tier III regulations. It will also enable each vessel to attain a maximum speed of more than 25 knots."

Quite so. Are the heavier and therefore 'draftier'? Iver Huitfelts not capable of more than 30kts with all four diesels engaged?

[Tempest414]

Thanks Richard for posting the article. The last paragraph was particularly interesting:

"The propulsion system will ensure a low underwater-radiated noise (URN) signature and will comply with IMO Tier III regulations. It will also enable each vessel to attain a maximum speed of more than 25 knots."

Quite so. Are the heavier and therefore 'draftier'? Iver Huitfelts not capable of more than 30kts with all four diesels engaged?

Both the Iver Huifeldt and Absalon classes can make 24 knots on two engines the IH class can make 30+ knots in 120 seconds from low speed with all four engine engaged

[Ron5]

All very quietly if the magazine is to be believed.

[NickC]

MAN Alpha Naval CP/FP Propellers brochure pdf, includes a pics of the three Iver Huitfeldt class ships and one undergoing underwater shock trials as an example ships using their propellers, would expect T31 to fit the later Mk5 generation introduced in 2010.

Propellers are the main source of noise but are also very important for vessel efficiency.

MAN Kappel claim with their advanced and unique Kappel propeller tip geometry able to reduce the difference in pressure between the pressure and suction sides of the propeller as the water moves from the high pressure area to the low pressure area with smaller flow over the tip creating lower tip vortices and so reduce the drag and lower the pressure pulses to reduce inception of cavitation/noise. The silent Kappel propellers are also applied for submarines with lowest acoustic signatures and surface ships employing stealth technology.

https://marine.man-es.com/docs/librarie ... b92b71a2_4

https://www.corporate.man.eu/en/press-a ... 58052.html

[MikeKiloPapa]

also to be remembered that T31 will be approx 1,000t lighter ship than IH.

Actually, the difference is in all likelihood much smaller. The RN is notorious for using its own/ different displacement definitions than everyone else. As such the 5700t quoted for T31 is almost certainly not a Full Load displacement figure , as is the commonly used metric for other nations warships , but rather Standard Displacement ie what the vessel actually weighs at a decided upon standard fit-out and trim.

That would square well with the IH parent design, which is 5462 t lightship, ca 6000t Standard , and 6645t FL displacement, giving a more plausible difference in standard disp. of around 300 metric tonnes.

[MikeKiloPapa]

The chilled water plant subcontract is going to Novenco AS, a Scandinavian firm [Oslo - Norway], to provide critical system capability for the HVAC (heating, ventilation and air-conditioning) system.

Though Novenco does have a norwegian branch, it is actually a danish company.

MAN Alpha Naval CP/FP Propellers brochure

In fact also designed and produced in Denmark, by what was formerly known as Alpha Diesel, now of course a part of the MAN ES conglomerate.
As i have alluded to before, the high amount of danish content in the T31 is likely a result of heavy lobbying from Naval Team Denmark and part of the deal , when handing over the IHs design to Babcock. Using the same suppliers and equipment as the parent design also saves time and money on redesign.

[ArmChairCivvy]

lobbying from Naval Team Denmark

I take it that the design bureau is just one member, and the rest are the potential suppliers?

[MikeKiloPapa]

Thanks Richard for posting the article. The last paragraph was particularly interesting:

"The propulsion system will ensure a low underwater-radiated noise (URN) signature and will comply with IMO Tier III regulations. It will also enable each vessel to attain a maximum speed of more than 25 knots."

Quite so. Are the heavier and therefore 'draftier'? Iver Huitfelts not capable of more than 30kts with all four diesels engaged?

Yes they are. Assuming that "more than 25 knots" isnt just an understated way of saying 30 kts, and that the T31 would end up being a little slower than the IHs, a possible technical explanation could be the use of MAN Alphas 5-bladed kappel CP propellers. Those are not quite as efficient as the 4 bladed versions used on the IHs, but are quieter and less prone to cavitate.

Speaking against that possibility is the added expense and complications incurred by choosing a different prop design, maybe even necessitating changes to hull design, rudders etc .
T31 being a somewhat lighter ship and with the same installed power, i would expect it to have similar if not slightly better performance than the parent design.

[NickC]

also to be remembered that T31 will be approx 1,000t lighter ship than IH.

Actually, the difference is in all likelihood much smaller. The RN is notorious for using its own/ different displacement definitions than everyone else. As such the 5700t quoted for T31 is almost certainly not a Full Load displacement figure , as is the commonly used metric for other nations warships , but rather Standard Displacement ie what the vessel actually weighs at a decided upon standard fit-out and trim.

That would square well with the IH parent design, which is 5462 t lightship, ca 6000t Standard , and 6645t FL displacement, giving a more plausible difference in standard disp. of around 300 metric tonnes.

As with the T26 quoted at 6,900t, whereas Australians quote 8,800t for the Hunter

MAN Alpha Naval CP/FP Propellers brochure

In fact also designed and produced in Denmark, by what was formerly known as Alpha Diesel, now of course a part of the MAN ES conglomerate.
As i have alluded to before, the high amount of danish content in the T31 is likely a result of heavy lobbying from Naval Team Denmark and part of the deal , when handing over the IHs design to Babcock. Using the same suppliers and equipment as the parent design also saves time and money on redesign.

Not surprised that the Danish Navy favoured Danish industry, but to be remembered Iver Huitfeldt class built for a very, very competitive price and Denmark has the industry and knowhow to produce some of the kit, the propellers being a prime example as know of no eqivalent UK company that produces ship propellers suitable and has been commentated above nearly all the kit installed on the T31 is foreign and would not be surprised if the steel is foreign as well, the majority of T26 steel is Swedish.

[MikeKiloPapa]

Thanks Richard for posting the article. The last paragraph was particularly interesting:

"The propulsion system will ensure a low underwater-radiated noise (URN) signature and will comply with IMO Tier III regulations. It will also enable each vessel to attain a maximum speed of more than 25 knots."

Quite so. Are the heavier and therefore 'draftier'? Iver Huitfelts not capable of more than 30kts with all four diesels engaged?

Both the Iver Huifeldt and Absalon classes can make 24 knots on two engines the IH class can make 30+ knots in 120 seconds from low speed with all four engine engaged

Yep....18 knots on 1 engine, 25 on 2 and 30+ knots on all 4....at 90% MCR. In terms of acceleration a more usable metric would be the requirement stipulated in the build specifications, to go from 5 to 25 knots in 60 seconds. Not too sluggish but not really fast either.....our old frigates (Peder Skram class) with their CODOG propulsion did 0-30 kts in less than 40 seconds and took just 36 seconds and 290 meters to do a full crash stop from 30 to 0 knots

[MikeKiloPapa]

lobbying from Naval Team Denmark

I take it that the design bureau is just one member, and the rest are the potential suppliers?

Yes as far as i can tell that is the case. I do sense a form of hierarchy within the export club though, with OMT definitely being a leading member.
From NTDs website : http://navalteam.dk/index.php?id=120

[MikeKiloPapa]

As with the T26 quoted at 6,900t, whereas Australians quote 8,800t for the Hunter

I wonder if the 6900t figure is lightship or standard displacement ? .....as for the Hunters 8800t , that is supposedly its mythical End Of Life displacement , which IMO is a bit of a bollocks term anyway ( Full load is full load....ie the maximum displacement of the design....it doesn't change unless you lengthen the hull) , but in the case of the Ozzies/RAN ,they are known for cramming their ships full of new heavy equipment when upgrading and modernizing and thereby sacrificing seakeeping and stability,. Which means the Hunter class will probably end up weighing 10kt but only be able to sail in sea state 2

Not surprised that the Danish Navy favoured Danish industry, but to be remembered Iver Huitfeldt class built for a very, very competitive price and Denmark has the industry and knowhow to produce some of the kit, the propellers being a prime example as know of no eqivalent UK company that produces ship propellers suitable and has been commentated above nearly all the kit installed on the T31 is foreign and would not be surprised if the steel is foreign as well, the majority of T26 steel is Swedish.

Without the heavy involvement of danish industry and thereby danish jobs, the RDN would NEVER have gotten vessel of the size and caliber of the Absalons/ Huitfeldts. Had we been forced to source the vessels outside DK i doubt if parliament would have approved anything larger than a poorly armed corvette half the size.
To return to the subject of thread....while there has been a lot of , more or less justified , gripe about the large amount of foreign content in the T31, im willing to bet that most of the less high profile but still valuable subsystems and equipment onboard will be British,....stuff like the PMS/IPMS , electrical systems, switchboards, furniture, panels, trimmings , pipes and plumbing , boats, davits etc...Soft kill protection systems/ decoy system is also likely to be indigenous ( Chemring Centurion perhaps ? )

[MikeKiloPapa]

Also , and i admit this is pure speculation but interesting nonetheless, there is the possibility that the tie-up between OMT and Babcock and the connection with danish industry might pay off in other ways in the future. See in the next 5-10 years the RDN have to replace at least 8 ships, the 4 Thetis class OPVs and 4 aging and obsolete environmental protection vessels.

There is a consensus that their replacements will both have to be larger and multi-role but also a lot more "fighty" . For the Thetis class replacement in particular what is being envisioned is either a large ice reinforced corvette/ light frigate (> 4000t) OR an ICE classed evolution of the Absalon /IH design.

The problem with both are that they are meant to be "real" warships......and the fact of the matter is that we(DK) have not designed and built a warship in a decade, and more importantly we now have nowhere to build them ! .....We have only yard left building new vessels, and all their hull fabrication takes place in Poland!....more to the point they have never built a ship of the size , complexity and to the naval standards that our new "Combat OPVs "requires. . But Babcock has .....or at least will have by the time we need hulls in the water ie around 2027.....

[ArmChairCivvy]

The gist was to sell them on
... now we don't even need to (before selling) do the final military fitting out as the Danish navy has kept that work internal; just a matter of sailing them over. Ohh, the price? A new formula: CostMinus

[shark bait]

I have to say I would like a F-class with

Faithful - Fearless - Firedrake - foresight - Fortitude

Batch 2

Foxhound - Fury - Favourite

So may good 'F' names, almost a little wasteful to give them to the T31.