Type 4X destroyer?

What's actually wrong with the powerplant?

It seems straight forward enough, turbines drive generators, powers motors drive ship.

Why is it so problematic?
 
Isn't the answer to this particular question...T31? The Danish ships the selected design is based on are their AAW platforms after all.
 
What's actually wrong with the powerplant?

It seems straight forward enough, turbines drive generators, powers motors drive ship.

Why is it so problematic?
T45 or T26? T26 propulsion is not quite as you describe.

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Interesting article on potential plans for a future AD destroyer to replace the Type 45s. Apparently to be based on the Type 26 frigate design, which, to me, is a bit strange, as the T26s are that bit smaller than the T45s.

Of course, it may just be Bae flying a kite and angling to keep their Scottish facilities going but it's an interesting discussion as the T45s will need replacing and now is a reasonable time to start thinking about it.

I can assure you that when the captains of a T26 and T45 drunkenly start comparing ship sizes in the mess they really would be down to getting their cocks out to compare size! (assuming they were male!) - the size difference in length is negligible and T26 will probably look a bit bulkier on the upperworks.
 
The T26 will probably be heavier - at least by end of life if the growth predictions come true. The really significant difference between T26 and T45 is hull depth (which is not the same as draught by the way). Generally speaking, for structural strength you want a length / depth ratio of between 10 and 13. Above 13 and you're into territory that might be described as "floppy". Which tends to lead to cracking problems (see T42BIII and T23 for details).

L/D ratio for T45 is a healthy 11.3. That for T26 is 13+
 
The T26 will probably be heavier - at least by end of life if the growth predictions come true. The really significant difference between T26 and T45 is hull depth (which is not the same as draught by the way). Generally speaking, for structural strength you want a length / depth ratio of between 10 and 13. Above 13 and you're into territory that might be described as "floppy". Which tends to lead to cracking problems (see T42BIII and T23 for details).

L/D ratio for T45 is a healthy 11.3. That for T26 is 13+
If 13+ is known to be bad ju-ju, what is the justification for saying "bollox to it, let's go with 13+" for T26?
 
It's close enough to 13 to scrape through. If only the midships area didn't have some huge openings in the upper-works.....
 
If 13+ is known to be bad ju-ju, what is the justification for saying "bollox to it, let's go with 13+" for T26?

Amongst other things, Bright ideas club demanded a flight deck long enough to land a Chinook on. No, not squeeze on, fully land on and drop the ramp big enough.
 
Possibly because money has been a little tight over the last ten years or so?



Except that it's not the Great White Turbine that is the principal issue - and while RR understandably don't offer the module any longer, the basic gas generator should remain supportable. Napier should ensure that the remaining issues are fixed or mitigated.



Sadly not. Two things. Firstly see comment on no money above. Secondly Govan will struggle to glue any more ships together in addition to it's current T26 workload. As noted elsewhere, there's limited capacity to build anywhere else in UK, even if there was any money.



If only the colonials didn't have the UK recruitment agencies trying to get the UK pool of design staff to go and work for them, thereby reducing the number of bodies available in UK.

Design skills and build are arguably work aroundable.

But I’d argue the T45 suffers from too many great white hopes In one package that never came to pass and with not much hindsight were not really wise.

Radar? Excellent, but 14 became 12, became 8, became 6, and no one else, not even us bought more. Bit orphan now.

Engines? Supposed to be the future, the Yanks would buy it, we’d buy it, the world would beat a path to our door and buy it. And? For political reasons, we bought it, not the LM2500 we wanted, the yanks ran away, the world ignored it. It’s now it’s the engine of which RR does not speak. And just to rub salt, the LM2500R delivers better fuel efficiency than the WR-21 was supposed to.

Weapons? Well, yet again, we ended up with what we didn’t want - for political reasons.
The world has snubbed SYLVER, we’ve got the orphan Sylver 50, and we wanted Mk41 - and SM-2 as it was backed by big money and had an upgrade path, and packed a very impressive anti surface punch. And here we are, Aster is a bit nice, but not getting much development, the Americans caught up and passed it by. SM-6 is pretty nifty, SM-3 can shoot down Darth Vader’s space ships. ESSM is looking very tasty too these days. Unless someone digs deep and rips out Sylver and fits Mk41, we’re now stuck in a very small missile backwater.

And the tale of woe that is the missing CEC, an opportunity missed.

I’d argue that T45 is rather like Bristol, promised too much, had too many new unproven systems, but endless delays allowed the world and other peoples technology to catch up, and it never quite got there.
 
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Design skills and build are arguably work aroundable.
With unicorns?

There are plenty of places where T45 has issues or could have done better. However, the issues are gradually being addressed and the alternate options are now just "if-only?" interweb debating points.

Without design skills and build facilities all the wonderful HMS Armageddon ideas are just ideas - or next years filing cabinet chucking out lists.
 
Circling back on this, I thought I remembered that the S1850M surveillance radar (in the T45 ships and the carriers, French and Italian frigates, a Korean LHD) is a variant of the SMART-L (found on the Huitfeldts and Dutch and German AAW ships) and yes, it is.
 
With unicorns?

There are plenty of places where T45 has issues or could have done better. However, the issues are gradually being addressed and the alternate options are now just "if-only?" interweb debating points.

Without design skills and build facilities all the wonderful HMS Armageddon ideas are just ideas - or next years filing cabinet chucking out lists.

The trouble remains, by the time we work through all the could have been done better design issues, they will be on the disposal list!

I can see them being pensioned off @ 20 years and something new bought.
 
The "could have been done better design issues" are a direct result of the atrophy of design skills and experience in the 90s, which ought to have identified some of the more obvious problems. Repeating that failure and hoping for a different result is probably not a good idea.

I can see them being pensioned off @ 20 years and something new bought.
For context, that would have Daring leaving service in 2030. That's 11 years away. She has yet to have her P&P upkeep period, which would knock a year or so off that.

That would require someone to find a lot of money and a lot of build capacity by 2027 at the latest. Without disrupting the T26, T31e or FSS programmes. Given that only one or at best two of our T26 (leaving six more to go) will have been delivered by then, I'd call it a bit of a stretch in build terms and magic money tree plus, plus, plus in terms of bunce.
 
Whatever the next AAW ship ends up being, one would hope that it is not based on T26.

Half the nausea in designing that ship resulted from the atrophying of ship design skills in the interval between T23 and T45, then to T26.

The "hullform" is just a shape. Developing that shape tends to cost <£5M, depending on the number of CFD analyses and model tests you end up doing. T26 hullform is optimised around one driving parameter, which is unlikely to be as relevant for an AAW ship.

You still have to produce the structural design, which will change depending on the weight distribution throughout the ship, which depends on the compartmentation and systems layouts. That's where you spend a lot of money, because the plate and section dimensions are necessarily different, as are the bulkhead positions, main machinery plant and other primary systems. All of which need detailed Class approval and then production drawings.

If you don't go through that exercise regularly, the people who know how to do it tend to retire / leave. It's not the sort of thing that you can just write in a book or a work instruction.
Really. most of the engineers I've worked with use a lot of books because they don't want to reinvent the wheel. I wonder why this is different.
 
Because the books tend to tell you the formulae - the "how it works". They don't tend to tell you the "why it works" and more importantly, they don't give you the experiential feel for whether a design and/or design calculation looks/feels right.
 
Which leaves the T45...
Whose propulsion system is currently being 'reworked' under Project Napier:


The T26 propulsion system is a combination of diesel electric or gas turbine (CODLOG) which is different to T45.

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