Shipbucket

I really hate that with the entire internet at our disposal the only good interal look at a DDGs engineering spaces is a commemorative wood engraving

Once again, thank you all for the information- I've learnt more about how modern warships work in the last few days than in the preceding few years! And that is a lovely top-down photo, Colombamike...just what I've been searching for.

Right! With all this input, I've put together some further drawings of the design, henceforth named the Burqbaş Class:





The design now uses the slightly longer Flight IIA hull (510') and so can no longer be described as a "small" destroyer; I've also corrected some artistic errors on my earlier drawings.

The second drawing gives a rough idea of the internal layout, although a lot of the equipment shown is representative (I haven't determined what diesel gensets would be appropriate, or what generators would work with the main GTs). I do have two questions, though:

1. Do we really need 3 GTGs in addition to the main turbines and diesels, given that the design is using an integrated power grid?

2. Those power levels aren't far off those I've seen quoted for a standard Burke: 72-80 MW compared to 88MW (excluding the 3 GTGs). Surely that can't be right?

Yasutomi
Enjoy If your read jap ?
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Why do you even need the desiels if you are going to maintain the GTGs? I'd say go with one of the other if only for logistics reasons.

The Fridtjof Nansen class have an combined Diesel and Turbine power, with an clever gear system, giving here the ability to choose what ever she want to drive on, in fact she can have port engine drive starboard propellers... that's fun... disadvantage is a bit more weight in the gears systems.

I am sure those gears are nothing compared to the two MRGs the current Burkes have. The ship definetly needs turbines, in the trawing above it looks like he has the LM2500s converted to gensets so he has three types of full sized ship service generators on there right now.

I know the GEAR PM models of the tico and perry have quite some flaws in the machinery setup representation, so don't use it as the best reference out there!

_________________
Drawings are credited with J.Scholtens
I ask of you to prove me wrong. Not say I am wrong, but prove it, because then I will have learned something new.
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yes but on Fridtjof Nansen class you can chose to use the LM2500 as an generator to power the electric engine, or you can have it geared directly in to the shaft... and the same can you do to the diesel generators on the Fridtjof Nansen class. she is of course smaller than the Burk, so small engine room, but she is one of the few with that complex engine layout.

during trials the frigate had the LM2500 powering the generator and the starboard propeller, while the electric motor (got power from the LM2500) powered the port propeller, at of course reduced power. or you can have all generators powering one of the propellers directly while the LM2500 take the other propellers. and that before they are using the electric engine, that can also be powered by the other small generator that are placed aft on the ship. or if you want to do it easy, just using the electric engine. reason for this on the Norwegian ship, is that we can't risk that the ship stop up because the electric engine fails, specially in the rugged North sea.

A little...not sure it's up to that! Still...the drawings alone are worth looking at.
The short answer as to why I am using three different types of generator is that it's a symptom of some woolly thinking! My initial idea was to simply halve the Burke's powerplant (as with DDV 1), but then I toyed with a CODAG arrangement; however, I'm now of the opinion that this won't fit my design.

From what I've learned in this thread, the GTs in the forward engine room drive the starboard shaft and those in the aft engine room drive the port shaft; now unless there is already some sort of cross-shaft clutch linkeage, I really don't see how you can keep the forward turbines and either remove or replace the aft ones without a substantial redesign- otherwise one of your shafts will either be underpowered or not powered at all!

Heuhen's solution, involving coupling each turbine to a generator as well as its own dedicated shaft, would make sense if you are simply deleting one turbine set from each engine room, but that isn't the plan...which is why I've fallen back on the IEP concept as that doesn't require mechanical connections.

So...under my slightly revised scheme (which I shall attempt to draw tomorrow), the two forward GTs will be replaced with uprated LM2500+G4s connected to generators. These will be linked tied into the ship's powergrid, along with the forward and aft service GTGs, to provide a total installed capacity of 74-76 MW (given that this is supposed to be an austere design an the Zumwalt manages with 78...I think that ought to be sufficient).

The aft GTs will be replaced by a pair of 34.6 MW Converteam Advanced Induction Motors (as fitted on the Zumwalt) which will drive the shafts; presumably this will remove the need for the mechanic gearboxes, which can be eliminated.

The only thing I'm not clear about at this stage is whether there where still be room for the middle GTG, given that the starboard engine will need to fit somewhere in this general area...unless it can be squeezed into the space occupied by the starboard gearbox on the standard Burke. But if that is the case, then the port AIM could be fitted into the port gearbox, which would leave free the space occupied by the real turbines...

I think it might be time to draw this project to a closes, so I've prepared three designs incorporated incorporating everything I've learned in this thread. I'd be really interested to hear which of the three (if any) you guys think is the best arrangement.

Option 1



In this design the forward turbines are replaced by uprated models with their gearbox replaced by generators; the aft turbines and midships GTG are replaced by the electric motors driving the shafts.

My main concern with this layout is the unevenness of the weight distribution: the bulk of the power train is concentrated beneath the already heavy forward superstructure with only the motors occupying the after engineering spaces. In addition, both of the turbines are situated on the starboard side. That said, it arguably requires the fewest changes to the standard Burke layout.

Option 2



In this design, the forward turbines are replaced by an electric motor driving the starboard shaft. The aft turbines are replaced by uprated model driving generators, the midships GTG is deleted and a second electric motor is squeezed into the aft engineering spaces to drive the port shaft.

This arrangement appears to offer a better distribution of weight, at least longitudinally (although the weight of the forward superstructure is no longer balanced by the weight of the engineering spaces directly below it). However, the design retains the long prop shafts that really shouldn't be a feature of an IEP layout and its is questionable whether the port motor would fit into an already crammed space without some modification of the interal structure.

Option 3



This final designs accepts that some modification of the interior is necessary. The forward turbine room is essentially deleted and the aft turbine room moved slightly forward, allowing the motors to installed in a dedicated compartment immediately aft. With the deletion of the midships GTG, the two turbines could potentially by installed symmetrically around the mid-axis of the ship, with the superstructure immediately overhead removed to allow the re-siting of the service shafts.

This is arguably the most efficient arrangement; however it does require a significant redesign of the hull between the two engineering spaces (althought it might be possible to "shift" certain compartments forward without too much fiddling).