Patrol Frigates

[sailor82]

Ingalls Shipbuilding recently presented two patrol frigate designs (Patrol Frigate 4501 and Patrol Frigate 4921) based off the Legend class National Security Cutters at the Pacific 2012 International Maritime and Naval Exposition. They also tried to sell the designs to the USN as either a supplement to or a replacement for the two competing LCS designs. The vessels will be targeted at an international market -- a market they expect will purchase 215 frigates over the next two decades. The 4501 is equipped for a broad range of peacetime tasks, while the 4921 is better equipped for anti-submarine warfare, anti-air warfare and anti-surface warfare.

[heuhen]

I think i saw a similar design proposal from one of the Americans naval ship yard for the Norwegian navy frigate program back in the day's

[TimothyC]

Darn, I was working on the earlier versions that became these, but you've done a good job with them.

They look good, but based on the text I've read on them after a quick google search, they have a 12 round GMLS forward for the ESSMs. To me that would imply the Mk 56 Mod 0 GMLS that can be found here. Any info on what the missile directors are planned to be? The old document that I have (Labeled 4920) shows a STIR over the bridge. I'm sure you can contact HII to get more info - in fact, I'm tempted to myself.

I'd also land the H-60 to fit with Shipbucket standards.

Edit: I've already sent a request.

[LEUT_East]

The design certainly gives the LCS a run for thier money - a worthy successor to the OHPs.

[Hood]

They look quite attractive for modern ships. Very interesting stuff.

[sailor82]

Updated drawings ...

I prefer these designs over the LCS as they have a 12,000 nautical mile range with a 60 day endurance as opposed to the LCS which has way shorter sea legs. As for the SPG-60 I have no idea where or how it would be placed. My impression is that it can be used with SPQ-9B as it is supposed to have the flexibility to be adapted for use by a variety of systems. The articles that I have read state that the PF would have a SSM capability, but it does not specifically identify the Harpoon. ESSM does have a SSM capability and possibly it could be armed with what ever system the USN decides to employ on the LCS. An older article (I believe it was a GAO publication) proposed that the USN versions would have SeaRAM and ESSM only. They are supposed to be also armed with six .50 cal HMG's with at least two (?) being a RWS.

[Thiel]

I doubt it'll have the full 12000nm range. It'll need more crew and carry a heavier load which will cut in to weight and space that used to store fuel. I wouldn't be surprised if it ends up closer to 9000nm. That's still significantly longer than the LCS though.

[TimothyC]

On PDF I have for the earlier drawing, the Harpoons are shown all on the stern, all of the way aft on what was the well ramp.

[sailor82]

Updated PF 4921 ... Also added a proposed alternative to the LCS.



@TimothyC - If you still have it, can you send me a copy of the *.pdf?

@Thiel - All Coast Guard cutters have long sea legs. I wouldn't think that this would be any different as they typically operate without any support.

[Thiel]

@Thiel - All Coast Guard cutters have long sea legs. I wouldn't think that this would be any different as they typically operate without any support.

But it's not a coast guard cutter any more. It uses the same hull as one, but it's filled with a very different set of equipment.
The Bertholf class has a set amount of weight and volume available. The 4921 uses the same the same hull, but unlike the Bertholf it uses naval manning standards and carries a significant amount of weapons. It's not unreasonable that it incorporates additional damage control measures since its intended to go places where you'd never dream of sending a Coast Guard vessel. All these things take up weight and volume and there's only really two ways to find it.
One is to allow it to be heavier and more cramped. This will make the ship ride deeper in the water and thus increase fuel consumption which will reduce its range. The cramped conditions will result in higher crew attrition and less storage space for spares, ammo and victuals thus reduce endurance.
The other option is to remove the equivalent volume and weight from the ship. Given the design there's really only two places you can cut in to and that's the hangar and the fuel tanks. And since reducing the hangar would reduce the designs potential significantly, the fuel tanks, and thus range, is the only place we can cut.
And that's why it won't have the same range as the Bertholf class cutters.

This is of course based on the assumption that no major redesigns will take place since that would defeat the point of the design.
(The point being that it's low risk and that most of the development has been paid already)