Grumman hydrofoil warship (HYD-2)

TomS

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Interesting indeed. First set are IIRC a Grumman destroyer escort concept. The second one looks German.

But neither are SCS.
 

TomS

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Interesting indeed. First set are IIRC a Grumman destroyer escort concept. The second one looks German.

But neither are SCS.
All are Grumman......
And not related to SCS...

Ok, so the first on is HYD-2 or a close relative. It probably deserves its own thread.
 

allysonca

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Airplanes I know, boats not so much........ thought you guys would like to see these models is all.....
 

TomS

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Sorry, shouldn't have snapped. I recommended that a mod move the first one to its own thread. The other one I can't place, but it should probably also gave it's own thread.
 

TomS

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Ok, this one is familiar. The Grumman M161 hydrofoil was built as Shimrit (built by Grumman in the US) and Shlomit (built in Israel). They were developed versions of the USN's experimental Flagstaff. They were seen as a.potential successor to the Saar missile boats but proved too expensive to operate and had only a short lifespan.
 

edwest

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Richard N

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Are these very interesting and unique models part of a collection or just passing through the shop?
 

Hood

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Ok, this one is familiar. The Grumman M161 hydrofoil was built as Shimrit (built by Grumman in the US) and Shlomit (built in Israel). They were developed versions of the USN's experimental Flagstaff. They were seen as a.potential successor to the Saar missile boats but proved too expensive to operate and had only a short lifespan.
Of the 12 planned, only 3 were built.
Around 1988-89 there were rumours of a new joint US/Israeli hydrofoil, perhaps further developed from the 'Flagstaff 2' but I've never seen any details. I assume if the reports were true that it would too be a Grumman design,
 

dan_inbox

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AFAIK, Grumman had decided to quit the hydrofoil business at the time of the Shimrit and Shlomit, and left (sold?) it to the Haifa shipyards.
 

TomS

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Ok, this one is familiar. The Grumman M161 hydrofoil was built as Shimrit (built by Grumman in the US) and Shlomit (built in Israel). They were developed versions of the USN's experimental Flagstaff. They were seen as a.potential successor to the Saar missile boats but proved too expensive to operate and had only a short lifespan.
Of the 12 planned, only 3 were built.
Around 1988-89 there were rumours of a new joint US/Israeli hydrofoil, perhaps further developed from the 'Flagstaff 2' but I've never seen any details. I assume if the reports were true that it would too be a Grumman design,
Combat Fleets 1993 says 15 were initially planned, reduced to three, but actually lists only two ships (Shimrit and Livnit, vice Shlomit) and states that a reported third unit (Snaprit) never actually existed. It also notes that the first two were built in parallel in the US and Israel, with many delays. Although the US unit was launched about two years earlier (1981), both entered service sometime in 1983. Grumman subcontracted the shipbuilding to Lantana Shipbuilding, Florida, while the Israeli unit was built at Israel Shipyard in Haifa. Performance never lived up to the advertised 52 knots; 47 was the maximum in trials and 42-45 was more typical in operation. Interestingly, the big pineapple dome is apparently not for radar, but for some sort of intercept (ESM/ELINT) array.
 
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Hood

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Jane's says 15 were initially planned, reduced to three. Combat Fleets 1993 actually lists only two ships (Shimrit and Livnit, vice Shlomit) and states that a reported third unit (Snaprit) never actually existed. It also notes that the first two were built in parallel in the US and Israel, with many delays. Although the US unit was launched about two years earlier (1981), both entered service sometime in 1983. Grumman subcontracted the shipbuilding to Lantana Shipbuilding, Florida, while the Israeli unit was built at Israel Shipyard in Haifa. Performance never lived up to the advertised 52 knots; 47 was the maximum in trials and 42-45 was more typical in operation. Interestingly, the big pineapple dome is apparently not for radar, but for some sort of intercept (ESM/ELINT) array.
My 1989-90 Janes says 12, so it looks like the programme had been trimmed before the programme got into the construction phase. Yes, I'm not sure what the ESM array was, certainly looks big.
 

TomS

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Interesting indeed. First set are IIRC a Grumman destroyer escort concept. The second one looks German.

But neither are SCS.
All are Grumman......
And not related to SCS...

Ok, so the first on is HYD-2 or a close relative. It probably deserves its own thread.
Somewhere I have a Jane's Surface Skimmers with a complete writeup, but in the interim, I found a good description in this article:

https://www.foils.org/wp-content/uploads/2017/10/0193-Hydrofoil-Development-and-Applications-Meyer-Wilkins-Jun-92-1.pdf

HYD-2 was a late 1970s design from Grumman. As designed, it was to be 2400 tons, 365 ft length overall, 116 ft beam over the aft foils. The foils described here are just two "inverted pi" foils (two struts connected to a single foil), with props in pods at the base of each strut. That's different from the arrangement in the model above, which has a third (fixed?) foil midships.

Propulsion consisted of two P&W FT-9 turbines for foilborn propulsion, one GE LM500 turbine for hullborne propulsion, and three Lycoming TF-35s for electrical generation. Speed was supposed to be 53.1 knots on foils in calm water, down to 51 knots in Sea State 6. Hullborne speed on one FT-9 was 26 knots, on the LM500 it was 15 knots.

Armament seems to have varied for mission, but it would have included some mix of "advanced" vertical-launched SAMs, Harpoon, lightweight torpedoes, Mk 48 heavyweight torpedoes. The Mk 48s are a bit late for the era; the 1960s Knox class design had provision for heavyweight torpedos, though they were never fitted. You can see what I think are Mk 48 tubes just below the bridge. Sesnors included unspecified radar and towed array for ASW (good luck towing an array at speed, though, or streaming and reeling it fast enough for sprint tactics. A fast-reeling variable-depth sonar would make more sense for a ship like this.) The helo was supposed to be LAMPS III.

I notice that the details of the model don't quite match the HYD-2 artist's conception. Aside from the foils, the sketch seems to show an actual hangar, while the model only shows a pad. The little partial model with a Grumman VTOL is closer to the drawing and might show a hangar door.

Edit: Replaced the previous version of this picture with a much improved copy.
 

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TomS

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Jane's says 15 were initially planned, reduced to three. Combat Fleets 1993 actually lists only two ships (Shimrit and Livnit, vice Shlomit) and states that a reported third unit (Snaprit) never actually existed. It also notes that the first two were built in parallel in the US and Israel, with many delays. Although the US unit was launched about two years earlier (1981), both entered service sometime in 1983. Grumman subcontracted the shipbuilding to Lantana Shipbuilding, Florida, while the Israeli unit was built at Israel Shipyard in Haifa. Performance never lived up to the advertised 52 knots; 47 was the maximum in trials and 42-45 was more typical in operation. Interestingly, the big pineapple dome is apparently not for radar, but for some sort of intercept (ESM/ELINT) array.
My 1989-90 Janes says 12, so it looks like the programme had been trimmed before the programme got into the construction phase. Yes, I'm not sure what the ESM array was, certainly looks big.
My mistake. It was actually CF that said 15. The program was almost certainly in constant flux.
 

TomS

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Still not finding much more detail. It appears the Grumman project number for this was M163 (the Flagstaff Mk IIs for Israel were M161). That matches the hull number on the drawing I posted, but not on the model.

There are a bunch of technical reports referenced online but they mostly haven't been uploaded anywhere. This one looks especially helpful and is available on the AIAA website, but $25 is a bit steep. (Anyone have an institutional login?):
  • "Grumman Design M163-A 2400 Metric Ton Air Capable Hydrofoil APR 78 Ship", by C.G. Pieroth, Grumman Aerospace Corp., AIAA/SNAME Advanced Marine Vehicles Conf., San Diego, Calif., April 17-19, 1978.
The first page of that AIAA paper does have a few more tidbits: aluminum hull, HY130 steel for the foils and struts, projected crew of 140 with growth to 155 with all accommodations midships near the point of lowest motion. All four props were to be controllable-pitch feathering designs to reduce drag when not in use. The FT-9 and LM500 could drive any/all of the hull or foil props.

Side note: It looks like the HYD-# was a Navy numbering scheme. A Boeing hydrofoil study from the same Advanced Naval Vehicles Concept Evaluation program was designated HYD-7.
 
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TomS

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Took a minute to spot this. It's a Grumman G-674 Nutcracker. The rig seems to be incomplete; there should be an articulated crane arm that holds that landing platform and rotates the aircraft into the hangar.

Here's the thread on this aircraft, complete with a bunch of photos showing the handing rig on an FF-1052 frigate.

 

Grey Havoc

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Saw the Nutcracker as well but didn't think to comment on it. D'oh!
 

Pioneer

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When I first looked at this beautiful model, one of the first things that tool my eye was the two smaller turret systems on roof (mid-ship?)
Looked like 30-35mm AAA type, so did some net surfing in an attempt to confirm/ascertain type..........

I came to the conclusion that they're most likely Oerlikon GDM-C 35mm/90's???

Also found this snippet of interesting info in relation to the Oerlikon GDM-C 35mm/90 mount:

"....A US Navy Foreign Ordnance Review Team concluded about 1971 that this version was better suited to US requirements, but none were purchased"

(Source: http://www.navweaps.com/Weapons/WNIT_35mm-90_KDC.php)


Regards
Pioneer
 

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TomS

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When I first looked at this beautiful model, one of the first things that tool my eye was the two smaller turret systems on roof (mid-ship?)
Looked like 30-35mm AAA type, so did some net surfing in an attempt to confirm/ascertain type..........

I came to the conclusion that they're most likely Oerlikon GDM-C 35mm/90's???

Also found this snippet of interesting info in relation to the Oerlikon GDM-C 35mm/90 mount:

"....A US Navy Foreign Ordnance Review Team concluded about 1971 that this version was better suited to US requirements, but none were purchased"

(Source: http://www.navweaps.com/Weapons/WNIT_35mm-90_KDC.php)


Regards
Pioneer
It's certainly possible. That was the original gun on the PF-109 design before the FFG-7 switched to the OTO Melara 76mm.

But it could also be the Emerlec EX-74 twin 30mm gun, which was developed around the same time and shows up in some other designs like the CPIC. They look really similar at the level of detail in the model. I'd lean toward the Emerlec because it's significantly smaller than the main gun, which seems to be a 76mm.

 

TomS

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The International Hydrofoil Society came through again! This is a report on Grumman's M165, a 70-knot hydrofoil using supercavitating foils and propellers.


It's clearly related to the M163 HYD-2 (also referred to as the Hydrofoil Ocean Combatant), but is smaller (~1300 tons) and has significantly more installed power -- three FT-9s instead of two. So a 50% increase in power to drive roughly half the displacement to 20% higher speed. And it sounds like there were doubts about the viability of supercavitating foils in "random" sea states. The report says the foils will inevitably "ventilate to atmosphere," which I interpret to mean that the supercavitating bubble will collapse and the foils will slam into liquid water at high speed, creating a very rough ride.

The drawings provide a sense of the arrangements (including armament). It also confirms what I suspected -- the twin small-caliber mounts aft are 30mm (and thus Emerlec EX-74s). The remaining armament is one 76mm OTO Melara gun forward, two banks of 11 vertical launch tubes for Standard MR along the sides of the deckhouse, and two forward-firing heavyweight torpedo tubes. The torpedoes are stowed in a novel configuration, stacked one on top of each other along the sides of the deckhouse above the torpedo rooms. The plan drawing says 5 each port and starboard, but the cross-section drawing shows the outlines of 7 weapons (possibly plus one in the torpedo tube), so the total capacity is anywhere between 10 and 16 heavyweight torpedoes.

Above-water sensors include a large 2-D air search radar (either SPS-49 or -59) and a couple of smaller radars in domes over the bridge. There would also be an SPS-55 surface search set (not shown in the drawings), and a fire control system derived from AWG-9 using two small antennas (one for volume search and one for illumination and fire control). Electronic warfare systems include the APR-59 ESM (from the E-2C) and ALQ-99 ECM (from the EA-6B). It's interesting that Grumman was leaning heavily on its aircraft electronics experience. A company with more shipbuilding expertise might have opted for different systems here.

The primary below-water sensor is the APRAPS (Active-Passive Reliable Acoustic Path Sonar) -- basically a large helicopter-type dipping sonar deployed below the ship on a cable. There is also room for a notional variable-depth sonar or towed array.

Edit: I've been comparing the model with this design and with the illustration of HYD-2, and I suspect that the model is closer in size to the M165 (~1300 tons) than the M163/HYD-2 (2400 tons).
 

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