Parvusimperator Designs A Frigate

I’ve talked about frigates before, and while I settled on the F100, it’s not ideal. Plus, designing things is fun. So I’m going to work up a frigate design sketch, and get exactly what I want. Unlike some of my other design sketches, this one will have requirements and some open questions. Consider it more of an RFP solicitation, because I don’t have the naval architecture skills to place components and be sure the ship is stable.

As with any good design, we’ll start with the mission first. We want a Frigate. Alas, that has become a rather nebulous concept these days, so permit me to resurrect an older, more appropriate term: destroyer escort. We want a relatively small1 ship geared toward the antisubmarine and antiaircraft2 missions. A token antiship armament will suffice.

For the antisubmarine mission, we want the following:

  1. Hangar space for two (2) LAMPS III[^helo] helicopters. These are critical. Helicopters allow for more coverage of the sea and rapid prosecution of contacts. I’m extremely disappointed with how few frigates accommodate two helicopters.

  2. A modern, variable-depth towed sonar array. This gives the best performance, and a modern towed array is a very useful and effective tool for hunting subs.

  3. A modern bow sonar. We’re looking for a good, effective bow sonar, that can accommodate future upgrades. Something reasonably sized and reasonably priced. This is less important than the towed array, so we’re open to savings here.

  4. A ‘beartrap’ hauldown device on the helicopter pad, to enable flight operations in a wider range of weather conditions.

For the Antiaircraft mission, we want the following:

  1. The Aegis Combat System, with NTDS datalinks and Cooperative Engagement Capability. This is the thing that’s going to hurt our budget, but we need it. This is the best integrated battlespace engagement system afloat. And it’s scaleable. We won’t want ballistic missile defense capability on these.

  2. Four multifunction PESA radar arrays, either SPY-1D(V) or SPY-1F(V). Here’s something that I’d need more information to choose from. I don’t know the weight, cost, and capability differences here, and frigates have gone either way on these3. I’m inclined to think the -1F is the way to go, but I won’t sell the bigger -D model short without data.

  3. A 3D Air Search radar to complement the SPY-1 array. Again, lacking the relevant comparison data on effectiveness and price, I can’t specify one. Offhand the SMART-L might fit the bill, but we might also have something smaller available that would be a reasonable cost compromise.

  4. Forty Eight (48) VLS tubes. No less. We want the American Mk. 41 or Mk. 57 tubes, since they can carry a wider variety of missile types. We’ll need to carry VL-ASROC or similar in addition to SM-2, SM-6, and ESSM SAMs. We’re not too particular as to layout though, and it may work better to use the peripheral mounting capability of the Mk. 57 tubes to place some on either side of the helicopter hangar, in addition to the usual forward mounting position on the bow.

  5. Two (2) Mk. 49 Rolling Airframe Missile Launchers. CIWS is important. Ask the USS Stark. Two launchers provide excellent coverage. And we’re going with missiles instead of Phalanx or Goalkeeper because the missiles are the more effective system.

  6. Three (3) Mk. 99 Fire Control System radars for terminal illumination. ESSM and SM-2 both feature terminal semi-active radar homing guidance, at least at present. These provide the radar.

That covers the key points. Let’s talk a few others.

As mentioned before, a token antiship missile armament will suffice. We’ll take eight Naval Strike Missiles4 in two quad launchers mounted amidships. Good enough for dealing with trouble if it shows up unexpectedly.

To save space and weight (and cost), we’re only requiring a 76 mm gun. Probably the Oto-Melara 76mm/62 Super Rapido. We’re also not too particular as to where it goes. We’d expect it to be in the ‘A’ turret (forwardmost) position, but it might work better in the ‘Q’ turret (amidships) position, as on the Oliver Hazard Perry-class. Make it work, that’s all we ask.

Lightweight torpedoes have long been standard equipment for prosecuting close submarine contacts. We won’t argue. A pair of triple-tube launchers for 324 mm torpedoes will do nicely.

We’ll also want some smaller guns to take out small attack craft or suicide bombers. We’ll go with a pair of M242 25mm autocannons in remote weapon stations, mounted amidships. Also a few 12.7mm M2 machine guns amidships, and a few more Ma Deuces on the fantail.

I’m not going to comment on ECM and decoys beyond specifying modern suites of both. Open source data on ECM system effectiveness is basically nonexistent, so I won’t comment further.

Now, let’s talk propulsion. We would expect some kind of combined diesel/gas turbine system5 with two screws. We would also like a maximum speed of at least 28 knots, and a range of 4,500 nautical miles at a cruising speed of 20 knots. A 20 knot cruising speed will enable her to keep up with just about any task force you please, and 4,500 nautical miles will do a good job of getting you from friendly base to friendly base, and refueling at sea is something we know how to do.

We would guesstimate a crew compliment, including officers and men for the ship as well as flight personnel, to be about 250. By modern standards, this is probably a little heavy, but that’s ok. We want to be sure there are enough men for proper damage control drills.

As for the hull and superstructure, we’d like good internal subdivision in the hull, and we won’t sweat an overabundance of low observability features beyond a bit of angling and avoiding corner reflectors. We’ll keep everything pretty conventional in terms of hull shape in order to keep the costs down. Also to keep stability up.


  1. Guesstimating based on other designs, 5,700 tons or so. Nothing set in stone, of course. 
  2. Okay, anti-antiship missile. 
  3. SPY-1D is used on destroyers like the Arleigh Burke and derivatives, as well as the F100. SPY-1F is used on the Fridtjof Nansens. If the F100 can accommodate the -1D, so can we, but the -1F might be a better buy. More data is required. 
  4. We would also accept, and very much like, eight HF-3s, but NSMs are smaller and cheaper, so they’re what’s required. 
  5. i.e. CODOG or CODAG depending on the economics of the engines and gearboxes in question. Again, I don’t have those numbers, so I’m not going to sweat picking one. I would also not say no to COGAG. 

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