(Conjectural Design) USN FFG 65 Class - DDG 51 Variant
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Author:  usna2k [ September 27th, 2012, 5:03 pm ]
Post subject:  (Conjectural Design) USN FFG 65 Class - DDG 51 Variant

First, again thanks to you for your feedback on my first stumble into your world... Something I always wondered would be what a DDG 51 destroyer would look like as a frigate. The drawing below is what I came up with, making use of the beautiful drawing of the Flight IIA produced by "Mihoshik." The first thing you notice immediately is that it looks very much like a DDG 51, but significantly shorter. This would conceivably be a replacement for the FFG 7 class frigates in USN service. In keeping with the frigate concept, I made the following modifications to Mihoshik's DDG:

- Eliminated one stack and cut a large portion of the center of the ship out completely (reflecting a reduction from 4x LM2500 engines to only 2, as in the FFG 7 class.
- One shaft vice two, and appropriate modifications to hull to accommodate it.
- Reduced freeboard and draft, as would occur with the significant reduction in displacement.
- One helo hangar vice two (new hangar is only on the centerline). No third gas turbine generator, so stack was eliminated.
- Deleted aft VLS (no space in frigate design)
- Weapons fit as follows:
- 1x 48 Cell Mk 48 VLS forward (replaces 32 cell Mk 41 VLS) - Ship capable of firing SM-2; ESSM; VLA. Tomahawk capability deleted.
- 1x Mk 75 76mm OTO Melara mount (replaces Mk 45 5"/62)
- Added 25mm mount amidships (in position they actually are installed in DDGs today) - 1 each port/stbd
- Added CIWS 1B mount on aft deck on either side of hangar (2 total)
- Replaced SPS-67 with SPQ-9B radar
- Modified antennae at top of mainmast to reflect current DDG 51 outfit
- Replaced SLQ-32 (V)3 ESM antenna with (V)2 unit.
- Reduction in SPG-62 illuminators to two; added deckhouse aft of stack to accomodate second antenna.
- Mk 32 SVTT moved from aft to amidships
- No weapon installed on forward deckhouse (space could be used for SeaRAM, RAM, etc, if necessary)

I omitted fin stabilizers, as I am not sure they would be required for a vessel as beamy as this, despite its shorter length, but they could be accomodated if necessary. I probably need to add a SLAD and RHIB forward of the CIWS mount as well, but chose not to do so at this time.

Comments are welcome and appreciated.

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Author:  eswube [ September 27th, 2012, 5:05 pm ]
Post subject:  Re: (Conjectural Design) USN FFG 65 Class - DDG 51 Variant

I'd say it will be a top heavy ship and the Phalanx is rather oddly placed.

Author:  Karle94 [ September 27th, 2012, 5:07 pm ]
Post subject:  Re: (Conjectural Design) USN FFG 65 Class - DDG 51 Variant

I`d say it`s too small. You need to lengthen it, possibly 20-30 meters longer.

Author:  Thiel [ September 27th, 2012, 5:10 pm ]
Post subject:  Re: (Conjectural Design) USN FFG 65 Class - DDG 51 Variant

Given how helo centric most post-Burke designs have been, I'd be very surprised if the USN would settle for a single hangar. Heck, the twin hangars are the only thing that's keeping the Perry's in the game.

Author:  acelanceloet [ September 27th, 2012, 5:48 pm ]
Post subject:  Re: (Conjectural Design) USN FFG 65 Class - DDG 51 Variant

interesting. while indeed top heavy quite a bit, something could be done about that.
weapon and drawing wise there is something to do though.
- first of all: it makes me think of the DDV-1 and later concepts for an burke hull with frigate abilities. ... ts&f=false
- vossiej recently updated the DDG-51 drawing. while the newer batches of this class are not yet updated to that standard, it would look much better to use this drawing for parts for your ship.
- as your helicopter hangar is relatively low on your drawing, I would say you could keep the SPY-1 lower then it is on the flight 2A ships, maybe even back to the DDG-51 position. this will keep top weight down
- lengthening the ship 20 meters wouldn't hurt. best would be to do so between the engine room and the helicopter hangar. will explain that in later points
- I wonder why your ship has the oto melara 76. if the 5 in fits, why would you not fit it?
- same for the Mk 48. note that the Mk 48 cannot fire ASROC nor SM-2MR.
- there is a lot of weight in the forward half of the ship now. this will make your ship heel forward.... unless you add a lot of ballast, which is less then ideal.
- single propellor means an reliability drop for lower cost. because of that, and because the design work for the DDG-51 class is of course already done, I would keep the double prop. if you keep the sinlge one, you are going to need an backup propulsion system somewhere, like the perry had.
- you will need bilge keels, even for an ship with an beam this large. active stabilising rudders would be an idea too ;)
- I agree with thiel about the heli hangar. 2 helicopters is what made perry attractive and what makes the burke an ASW platform.
- you'll want the Mk 32 torpedo tubes as near to the helicopter hangar as possible, so you can share the magazines.
- look in the USN parts thread and the belowdeck parts thread for any parts not mentioned above.

so, what I would do:
- lengthen the ship with 20 meters. in that space, I'd add an small uptake (for diesel generators) which both make your turbine space spacier and at the same time act as counterbalance to get the CoG more aft.
- go to double hangar. put one phalanx on top of the hangar, move the other one forward (why would you opt for an less then ideal setup when space is free for the ideal one!)
- lower the SPY-1. maybe even consider an smaller SPY-1 radar version, or the switch to the NTU radars
- use as much as possible from the burke hull, especially sonar and propulsion.
- put 2 blocks Mk 56 or 1 block Mk 41 self defence length between the hangars, purely for ESSM. 24 or 32 missiles respectively are able to do the ships self defence, leaving the forward Mk 41 to SM-2MR, ASROC and Tomahawk.
and other then that I would keep DDG-51 systems as much as possible, maybe only downgrading some high cost stuff like the 'crows nest' IFF or, as you have done, the SLQ-32 to V2.

Author:  KHT [ September 27th, 2012, 5:59 pm ]
Post subject:  Re: (Conjectural Design) USN FFG 65 Class - DDG 51 Variant

I kind of like the current appearance, makes it look like a 21st century CDS.
Note that above is not advice, and should not be treated as such. Merely a comment on the current aesthetics. :D

Author:  klagldsf [ September 28th, 2012, 3:59 am ]
Post subject:  Re: (Conjectural Design) USN FFG 65 Class - DDG 51 Variant


It's very awkward to try and shoehorn a (very) large destroyer hull into a frigate solution. I'm betting that even if you reduce the beam you'll still end up with some ridiculous hull speed figures. But on the other hand you'll end up with a very stable platform!

EDIT: Especially given your potential options, that's also some very lousy CIWS placement.

Author:  bezobrazov [ September 28th, 2012, 12:40 pm ]
Post subject:  Re: (Conjectural Design) USN FFG 65 Class - DDG 51 Variant

In this configuration, I'd try to cut down the forward superstructure one deck to enhance its stability. The SPY-dish should still fit if you do this carefully!

Author:  gordo8000 [ September 28th, 2012, 12:55 pm ]
Post subject:  Re: (Conjectural Design) USN FFG 65 Class - DDG 51 Variant

First of all, I like the look. Very 21st century. Now on to the critique, if you moved the CIWS to the top of the hanger you could place a RHIB in its place. I think that you should also keep the Tomahawk capability and add a few .50cals.

Author:  usna2k [ September 28th, 2012, 3:26 pm ]
Post subject:  Re: (Conjectural Design) USN FFG 65 Class - DDG 51 Variant

Ok folks, I went back to the drawing board and make some significant changes to the ship design. It is now a dual hangar frigate; the CIWS have been located fore and aft; there is a small stack aft of the main one to accomodate diesel generator exhausts; the entire ship is about a deck shorter in height. Added APUs and Fins from acelanceloet's FFG model; made other various changes as shown. Length is unchanged. Should have stated Mk 41 48-cell launcher yesterday, not Mk 48. Tomahawk will not be added. Only VLA, SM-2 and ESSM. SPY radars relocated to compact deckhouse atop the shortened bridge superstructure. Mast shortened as well. Rationale for 76mm is that bow is shortened vs. DDG 51 and less space available for 5", especially with 8 additional VLS cells.

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