Type 26 Frigate (City Class) (RN) [News Only]

[seaspear]

Would other customers of the T26 though have the option to upgrade this and what in speculation do you view as the best combination money not a problem

[Ron5]

Another way of looking at it is that the FREMM has the same propulsion system of the Type 23 first introduced in 1989. Back then, a technical choice made because of the lack of a more powerful GT.

The more recent FREMM decision was, of course, taken for political reasons. The American GT chosen is assembled in Italy. Pretending that somehow the choice was driven by capability issues is rather silly given the previous comment that the Italian navy wants more powerful diesels to make up for the (comparatively) weedy GT.

By the way, the Type 26 will be able to exceed 15 knots on diesel electric. Not sure why Gabby thinks otherwise.

[Ron5]

In other words, lot of extra cost & complexity that gains nothing which could so easily been avoided by the choice of a more powerful GT.

There is no doubt is is more costly and complex, but it would increase the total electrical capacity of the ship considerably, so thats your trade off.

As it stands the T26 is trying to be as low risk and low cost as it can be, which I totally agree with, which is obviously why it has been given the simpler propulsion method.

That's a major assumption on your part. All that has been claimed is that under GT propulsion, the FREMM's can be used to generate power. Assuming that is correct, how much power? and do the ships systems allow for that power to be used in addition to that generated by the diesels. My guess based on how other hybrid warships work, is that the the GT propelling the ship & at the same time generating electricity, merely allows the diesels to be shut down in order to save fuel.

Postulating that extra electrical capacity could be generated by the ship switching to GT propulsion would be rather weird: "Engage turbines Scotty, so we can fire our rail guns & lasers. Aye Captain but that will double our speed and makes us unable to perform ASW".

[Gabriele]

Another way of looking at it is that the FREMM has the same propulsion system of the Type 23 first introduced in 1989. Back then, a technical choice made because of the lack of a more powerful GT.

The more recent FREMM decision was, of course, taken for political reasons. The American GT chosen is assembled in Italy. Pretending that somehow the choice was driven by capability issues is rather silly given the previous comment that the Italian navy wants more powerful diesels to make up for the (comparatively) weedy GT.

By the way, the Type 26 will be able to exceed 15 knots on diesel electric. Not sure why Gabby thinks otherwise.

CODLAG is a superior, more flexible propulsion arrangement, well worth the greater complexity of the gearbox.

The want of greater speed is tipycal of the italian navy, which has it almost for tradition. We build quick ships, and the Isotta Franschini diesels have not quite delivered what was expected of them, and the Navy wants to make at least 18 knots on the diesels only. The GT has nothing to do with that.

The claim about more powerful GTs making the CODLAG advantages not desirable is not even worth commenting. CODLOG is a poor man's choice. For saving pennies on the gearbox, the Type 26 will not be able to draw the full benefit that its powerful diesels and GT could deliver working in combination.

[Ron5]

Another way of looking at it is that the FREMM has the same propulsion system of the Type 23 first introduced in 1989. Back then, a technical choice made because of the lack of a more powerful GT.

The more recent FREMM decision was, of course, taken for political reasons. The American GT chosen is assembled in Italy. Pretending that somehow the choice was driven by capability issues is rather silly given the previous comment that the Italian navy wants more powerful diesels to make up for the (comparatively) weedy GT.

By the way, the Type 26 will be able to exceed 15 knots on diesel electric. Not sure why Gabby thinks otherwise.

CODLAG is a superior, more flexible propulsion arrangement, well worth the greater complexity of the gearbox.

The want of greater speed is tipycal of the italian navy, which has it almost for tradition. We build quick ships, and the Isotta Franschini diesels have not quite delivered what was expected of them, and the Navy wants to make at least 18 knots on the diesels only. The GT has nothing to do with that.

The claim about more powerful GTs making the CODLAG advantages not desirable is not even worth commenting. CODLOG is a poor man's choice. For saving pennies on the gearbox, the Type 26 will not be able to draw the full benefit that its powerful diesels and GT could deliver working in combination.

The one and only reason for CODLAG is to use diesel-electric power to increase the propulsion power over pure gas turbine. The Type 23's pioneered this approach 30 years ago.

If that increase in power is not required because the GT is powerful enough on it's own, then CODLOG is the superior engineering solution on the grounds of less space, lower weight, lower thru-life costs, simpler, less man-intensive maintainability & increased reliability.

Waving your arms around making jingoistic, wild generalities, doesn't change those facts.

And yes, the Italian navy does have a reputation for preferring fast ships. <insert joke here>

[Tiny Toy]

If that increase in power is not required because the GT is powerful enough on it's own, then CODLOG is the superior engineering solution on the grounds of less space, lower weight, lower thru-life costs, simpler, less man-intensive maintainability & increased reliability.

It is a superior engineering solution on those grounds. IEP is another superior engineering solution on the grounds of flexibility, fuel efficiency, noise reduction, and transmission repairability.

[Gabriele]

If that increase in power is not required because

you can't / won't afford it, then...

Fixed that for you.

Arsehole.

[RetroSicotte]

All right, both of you chill it. Immediately. Take it to PMs if you must, but that debate ends right now. Discussion yes, both it's clear that you're both getting too heated to let it continue in this manner.

[Ron5]

Let me please make one more post. I've suffered quite a bit of personal abuse from young gabby in this and other posts, so I think you should indulge me.

At its top speed (say 30 knots), the Type 26 will only be using its 36+ MW gas turbine so if it comes under attack, 100% of its diesel electric system is available to run & fight the ship. 4 MTU gensets each capable of 2.9M. In total: 11.6 MW.

At its top speed (say 30 knots) the Italian FREMM will be using its 32 MW gas turbine plus it's two EM's each requiring 2.5 MW. I believe the latest Italian FREMMs have 4 2.8MW gensets, in total 11.2 MW. Assuming no losses in the drain train (actually losses are quite significant), only 11.2MW minus 5 MW = 6.2 MW to run & fight the ship.

In other words, thanks to its more powerful gas turbine that does not require to be supplemented to provide max speed, at top speed the Type 26 will have almost double the amount of electrical power available. Enough for a couple of lasers perhaps?

Obviously as both ships speed decreases, the power gap lessens until the Italian ship is only running on its gas turbine.

Another way of looking at it is: as the Italian ship accelerates to top speed, the captain will have to chose which ships systems to turn off in order to divert electricity to propulsion.

P.S. I should mention that the French chose CODLOG for their FREMMs, not CODLAG, hence my calling out Italian FREMMs.

[Ron5]

If that increase in power is not required because the GT is powerful enough on it's own, then CODLOG is the superior engineering solution on the grounds of less space, lower weight, lower thru-life costs, simpler, less man-intensive maintainability & increased reliability.

It is a superior engineering solution on those grounds. IEP is another superior engineering solution on the grounds of flexibility, fuel efficiency, noise reduction, and transmission repairability.

I most certainly agree for large ships like the QE's & Zumwalts. In particular the freedom to locate the generators wherever you like, as shown most strikingly in the QE design, is most valuable. For smaller ships, IEP is kinda expensive and the freedom of location can't really be exploited.

[CR4ZYHOR5E]

Good discussion. For me, Ron's point about the extent to which the chosen solution meets the design brief/requirement is the compelling one; i.e. scrutiny of the decision to go with CODLOG comes down to whether the GT [alone] meets the targeted power requirements? If yes, then you look like a hero that's removed cost/complexity from the equation. If no, then you look like a chump, for sure.

[Tiny Toy]

For smaller ships, IEP is kinda expensive and the freedom of location can't really be exploited.

Regarding expense, remember that up front costs are offset by the full lifecycle fuel reduction savings (and possibly emissions savings if emissions eventually get round to being taxed in a coherent manner).

I don't see freedom of location as being as important as the flexibility to replace with new prime movers as the technology becomes available - marine fuel cell propulsion particularly is developing at an astounding rate and certainly may become more desirable than diesel/gas during the operating lifetime of any ships we design today.

[ArmChairCivvy]

Good discussion. For me, Ron's point about the extent to which the chosen solution meets the design brief/requirement is the compelling one; i.e. scrutiny of the decision to go with CODLOG comes down to whether the GT [alone] meets the targeted power requirements? If yes, then you look like a hero that's removed cost/complexity from the equation. If no, then you look like a chump, for sure.

Whatabout single point of failure (resilience, recoverability... staying in the fight)?

5 or 10 pages back I made the comment about potentially going down 2/3s in weight and by a half in size, by having the single turbine (MT30 leading the pack as for now) backed up by a
""[Reports on the performance of the] 5-megawatt HTS motor under both full power and realistic operating conditions continue to be impressive," [said Rear Admiral Jay Cohen, Chief of Naval Research.] "The successful application of HTS technology to naval ship propulsion would provide the Navy with unique design options for our All-Electric Ship Programs."

[90inFIRST]

This has been a really good discussion and I now have a better understanding of the RN's choice of CODOG and the change from power/propulsion from the T23, though gabby will disagree I think this is the correct choice for the RN

[ArmChairCivvy]

When the Chair of the Defence Select Committee wrote a letter for the Minister to answer, that was quite unusual (for one particular programme).

Further, Future Proofing was one of the sub-headings.

None of the stuff we have been discussing was touched upon.

[The Armchair Soldier]

All right, both of you chill it. Immediately. Take it to PMs if you must, but that debate ends right now. Discussion yes, both it's clear that you're both getting too heated to let it continue in this manner.

Just to add to this. Ron and Gabriele, you might want to look into using the Friends and Foes system which we have here. Add each other as Foes and you will no longer be able to view each other's posts. Just a suggestion. Now, back to the Type 26.

[Ron5]

For smaller ships, IEP is kinda expensive and the freedom of location can't really be exploited.

Regarding expense, remember that up front costs are offset by the full lifecycle fuel reduction savings (and possibly emissions savings if emissions eventually get round to being taxed in a coherent manner).

I don't see freedom of location as being as important as the flexibility to replace with new prime movers as the technology becomes available - marine fuel cell propulsion particularly is developing at an astounding rate and certainly may become more desirable than diesel/gas during the operating lifetime of any ships we design today.

Excellent points.

[Ron5]

All right, both of you chill it. Immediately. Take it to PMs if you must, but that debate ends right now. Discussion yes, both it's clear that you're both getting too heated to let it continue in this manner.

Just to add to this. Ron and Gabriele, you might want to look into using the Friends and Foes system which we have here. Add each other as Foes and you will no longer be able to view each other's posts. Just a suggestion. Now, back to the Type 26.

My problem is that I'm a huge fan of his blog

[Ron5]

Good discussion. For me, Ron's point about the extent to which the chosen solution meets the design brief/requirement is the compelling one; i.e. scrutiny of the decision to go with CODLOG comes down to whether the GT [alone] meets the targeted power requirements? If yes, then you look like a hero that's removed cost/complexity from the equation. If no, then you look like a chump, for sure.

Whatabout single point of failure (resilience, recoverability... staying in the fight)?

5 or 10 pages back I made the comment about potentially going down 2/3s in weight and by a half in size, by having the single turbine (MT30 leading the pack as for now) backed up by a
""[Reports on the performance of the] 5-megawatt HTS motor under both full power and realistic operating conditions continue to be impressive," [said Rear Admiral Jay Cohen, Chief of Naval Research.] "The successful application of HTS technology to naval ship propulsion would provide the Navy with unique design options for our All-Electric Ship Programs."

That (what about redundancy/survivability?) is an excellent question. Unfortunately that's a topic that navies keep very close to their vest. I do not know if CODLOG or CODLAG is best for this. In both systems, the diesel gensets will be kept in well separated machine rooms with at least some of them also separated from electric motors & gas turbines. It's obviously very important but which is superior. IDK.

To me, the T45 design looks outstanding in this regard. Two mechanically independent drive trains, each driving one shaft, with all key components in well separated machine rooms. One more plus for Tiny's IEP.

By the way, the Zumwalts originally were designed for advanced electric motors but the technology wasn't even close to being mature enough. I believe they fell back to the T45 motors.

[ArmChairCivvy]

That (what about redundancy/survivability?) is an excellent question. Unfortunately that's a topic that navies keep very close to their vest. I do not know if CODLOG or CODLAG is best for this. In both systems, the diesel gensets will be kept in well separated machine rooms with at least some of them also separated from electric motors & gas turbines. It's obviously very important but which is superior. IDK.

To me, the T45 design looks outstanding in this regard. Two mechanically independent drive trains, each driving one shaft, with all key components in well separated machine rooms.

Ehh? We are the best friends after all? Let's keep it that way.

The T45 design was leading edge, and I still don't understand where the power mgt problems are in the big picture (were there none, it would have been replicated down to te T26... same size of ship after all... a cruiser, or both of them actually).
- I know that the turbine choice was flawed, it is a dead end and there are no spares (single point of failure? A turbine goes out, and a £bn of tax payers money will sit by the quayside)
- I am not putting any blame on RR... they have learned, improved and continue to deliver the best-in-class

[desertswo]

In other words, lot of extra cost & complexity that gains nothing which could so easily been avoided by the choice of a more powerful GT.

Not so much. One of those "factoids" that is little known outside USN main propulsion engineering circles is that the endpoint of available power output of the LM2500 has never been achieved, and frankly, at this point in the evolution of that particular piece of technology which is no longer "state of the art," it never will. In point of fact, the basic turbine design is better than 50 years old. That fact, as much as anything, is driving new USN warship designs to the MT-30, as it IS state of the art, and IEP.

So anyway, why was the endpoint of GT power output never reached? It never reached the endpoint of power turbine power output because the torque developed by the Power Turbine section of the GT at maximum plant designed RPM (not the GT's maximum RPM) stress cracks developed in the spline shaft, 1st Reduction Pinion Gears, 1st Reduction Gear, and 2nd Reduction Pinion Gears. Only the 2nd Reduction Gear, colloquially known as the "Bull Gear" due to its enormous size, was spared that insult. It started with the DD-963/DDG-993/FFG-7 and CG-47 hulls, and to my direct knowledge; I say again, to my direct knowledge, was not solved before the first DDG-51 came off the builder's ways. No matter how many wiz kid, brainiac, booger eating, pocket protector wearing, pencil necked geek REAL engineers (as opposed to we mere Archaeologists ) from GE, Westinghouse, DeLaval, or (insert name of über-magnificent firm HERE) tried to wrap their expensive gray matter around the problem, they didn't "git 'er dun!"

As I said, perhaps the problem was solved for Arleigh Burke; I sure hope so, but who knows? Now, that didn't mean that these ships couldn't complete their missions as designed. It's just that they had/have "war reserve modes" that they could go to that might lead to a new crack or three, but otherwise operated with some limits, well known in the GT community, that were transparent to everyone, including the bad guys.

Anyway, let us hope that no matter how employed, no such limits exist for the MT-30.

[~UNiOnJaCk~]

Occasional bouts of hostility aside i have enjoyed following the more academic parts of the recent discussion. Plenty of good points well argued which has left a lot to mull over and consider.

[Ron5]

I'm a tad surprised that there seems to be so little love for Rolls & its MT30 in the UK.

Both the latest two US flagship programs, LCS & Zumwalt have specified the turbine over home grown completion and it's won a number of competitions in countries not generally known for buying British kit like Korea. Amazing if you think about it. Truly world beating product.

I don't know if folks here remember, but a few years back, RR proposed an MT50. Quietly dropped later, it presumably was just too powerful.

But can you imagine a Type 26 with one of those beasts? Another 25 or so MW. Water skiing behind a 7k ton frigate.

[desertswo]

I don't know if folks here remember, but a few years back, RR proposed an MT50. Quietly dropped later, it presumably was just too powerful.

But can you imagine a Type 26 with one of those beasts? Another 25 or so MW. Water skiing behind a 7k ton frigate.

It wouldn't/couldn't be able to tow you thusly, as I believe I've tried to explain here or some other thread on this site, as sheer power available alone is not what gets the job done. The Freedom class LCS goes fast not due to the presence of the MT-30 alone. She goes really fast because of a hull form that is: a) optimized in terms of length, breadth, and displacement, for going fast; b) has a near total lack of underwater projections, and; c) uses propulsion jets in lieu of both screws and rudders, thus no associated drag. LM2500s would have served equally as well in that regard.

[Dave]

I don't know if folks here remember, but a few years back, RR proposed an MT50. Quietly dropped later, it presumably was just too powerful.

But can you imagine a Type 26 with one of those beasts? Another 25 or so MW.

Not to mention you suddenly have plenty of excess power for all the new goodies like lasers.

I wonder how feasible a midlife upgrade to the GT would be when they decide they need the extra power.