Offshore Patrol Cutter Update, June 2012

Several documents have emerged recently that provide more information on the proposed Offshore Patrol Cutter (OPC), also known as the Maritime Security (Cutter), Medium (WMSM). This builds on information previously published (here, herehere, here and here).

The Request for Proposal included a projected build schedule for the first 11 ships.

  • FY 2016 Detail Design
  • FY 2017 OPC#1 Construction begins
  • FY 2018 OPC#2
  • FY 2019 OPC#3
  • FY 2020 OPC#4 and #5
  • FY 2021 OPC #6 and #7
  • FY 2022 OPC #8 and #9
  • FY 2023 OPC #10 and #11

There is a notation that the average cost of units 4-9 shall be $276M in FY2016 dollars. (Looks like there might be potential for a multi-year contract here.)

One of the big surprises to me (found in the Fleet Mix Study) was that the OPCs are expected to essentially take over all Alaska Patrols.

The draft Request for Proposal (RFP) also includes a requirement to equip all of them “to operate in areas of broken plate, pancake, and sea ice ranging from 10 to 30 inches thick.” Along with this, came a requirement to be able to operate an ice capable small boat as well. OPCs are also to have automated topside de-icers.

These characteristics combined with the Commandant’s affirmation that the ships should be capable of boat and helicopter operations in state five seas mean these ships will be very much more capable than the WMECs they are nominally replacing, and at least to some degree, that they are taking over duties previously assigned to 378s.

Towing ability to 10,000 tons is required, same as the 378s.

The ships are expected to be able to do Fueling at Sea (FAS), Replenishment at Sea (RAS), Vertical (Helicopter) Replenishment or VERTREP, and to refuel smaller vessels (apparently reflecting an expectation of sustained operations with WPCs or WPBs at locations remote from their bases).

Minimum ranges was specified as 7,500 nautical miles. (This is a reduction from 8,500 miles). Typical operations as outlined in the Concept of Operations (CONOPS) were 14 days between refueling, 21 days between replenishment, and 45-60 day patrols. It also stated there would typically be a four to six week inport “Charlie” (stand-down/maintenance) period after each patrol; a six to seven week dockside availability every two to three years; and a seven to eight week drydocking every four to five years. “In addition, the cutter will undergo 3-4 weeks of training and evaluation every 10-24 months.”

An expectation that the ships might operate with Expeditionary Strike Groups (ESG) was apparently a recent addition. This helps establish a floor for the ships’ maximum speed, since all the units typically operating in an Expeditionary Strike Group (LHAs, LHDs, LPD, LSDs) have speeds of 20 to 24 knots. When the current generation of LSDs is replaced in the not too distant future, all will do 22+ knots. Of the three ships that typically make up an ESG, the largest (LHAs or LHDs) all do at least 24 knots and frequently act as small aircraft carriers. If the OPCs are to be fast enough to stay with these ships and hopefully maneuver around them, then 25 knots appears to be a minimum rather than a nice to have.

The crew is not to exceed 100, but additional birthing must also be available for a 5 person AvDet and a 5-11 person “Signals Intelligence Support Element,” “and possibly others.”

There was reference to ballistic protection, that I had not seen before.

“The WMSM will provide increased protection for (sic.) small caliber weapons and shrapnel fragmentation around the bridge, CIC, and magazine spaces.”

The ships are to be built the American Bureau of Shipping Naval Ship Rules, but will not have explosive or underwater shock hardening.

Again we do not have access to the draft specifications, but we can deduce some details of the proposed equipment from the Allowance Equipage List included in the Draft RFP. All the systems below are referenced. (In a few cases there may be duplicate listing if different nomenclature is used for the same system.) The outfit, in most respects, repeats or even improves on that of the National Security Cutter:


  • Military SAT com
  • Tactical Data Link System
  • IFF
  • SBU (presumably “Sensitive but Unclassified”) Network
  • SIPRNET (Classified Network)
  • NIPRNET (Unclassified Network)
  • Entertainment System


  • TSR-3D RARAD System, a multimode surface and air surveillance and target acquisition radar
  • Electro-Optic/Infrared Sensor system


  • Mk 48 mod 1 Gun Weapon System (pdf), which includes the Mk 110 57mm gun, AN/SPQ-9B  Surface search and Fire Control Radar, Electro-Optical sensor system Mk 20 mod 0, the Mk 160 GCS Mod 12, and Mk 12 Gun Computer System
  • Mk 15 mod 21-25 CIWS (Phalanx)
  • Mk 38 mod 2 25 mm
  • Gun Weapon System (.50 cal.) SSAM
  • Four crew served .50 mounts including Mk 16 and Mk 93 mod 0 or mod 4 mounts
  • Mk 46 optical sight

Electronic Warfare:

  • Mk 53 Decoy launcher
  • AN/SLQ-32 (v)2


  • Encrypted GPS
  • Electronic Chart Display and Information System


  • Ships Signals Exploitation Space (A change from SCIF (Sensitive Compartmented Information Facility))
  • Special Purpose Intel System


  • Hangar for helicopter up to and including Navy and Coast Guard H-60s
  • Facilities for the support of unmanned Aerial Systems (UAS)
  • Visual Landing Aids

24 thoughts on “Offshore Patrol Cutter Update, June 2012

  1. Cheapest de-icing will always be an E-2/3 with a louisville Slugger, you can get the former from Cape May and the latter from FEDLOG for $50. Topside auto de-icing sounds like an EM’s nightmare.

    SCIF = SSES as far as I can tell

    LM2500 is the most space efficient way to get those speeds. I like the idea of a diesel electric plant that gives you 10-14 kts and a sprint/fleet speed via the turbine. It offers enough redundancy to allow you to get home either way, allows you to tool about for patrolling, and if your can get 26kts with a LM2500 on a WMSL, you’d think you can get much more speed in the OPC.

    sounds like no Nulka, just SRBOC.

    I can’t understand why the WMSM would need MK38, MK 15, and ROSAM’s. That seems redundant, its more than the WMSL has by alot. With that said, I never understood building a WMSL with a positive pressure core but requiring manned gun crews, are we building for the threat or not? Gonna need more ET’s on the WMSM than on the WMSL at this rate.

    • Please, no LM2500! The RFP is already asking for the same weapons and radar as WMSL. If you add the same propulsion, how are these ships ever going to cost less than $300 million? (In FY16 dollars, no less)

  2. Good summary. I was thinking the same thing: OPC is morphing into a 378 replacement. Or a poor man’s NSC!

    Mind you, that’s not necessarily a bad thing… as long as the final design doesn’t blow past that $276 million cap. Color me slightly skeptical, I guess.

    I struggle with some of the “gold plating”, which is only necessary for that chokepoint escort role, which really should be left to the NSCs:
    – 57mm gun (why not refurb the 76mms?)
    – 3D C-band radar (2D X-band good enough)
    – SPQ-9B fire control (EOSS good enough)

    CIWS doesn’t appear in the GFE list in Schedules B/C, so maybe it’s only a provision for future installation. Smart move.

    Speed requirement is still a bit vague. Few MSC ships go above 20kts. OPC shouldn’t be doing close escort of an ESG – it’ll be screening surface contacts at some distance. So overall, 22kts still good enough?

    • My understanding is that specs require diesel propulsion, so turbines are out. There are lots of diesel ships with speeds above 25 knots out there. Going from 22 knots to 26 knots would probably require doubling the horsepower. Going to a hybrid (Geared diesel for high speed electric for cruise) or integrated diesel electric and ships service system like the Lewis and Clark class dry cargo ships offers an economical way to have both the high speed and the economical cruise.

      Earlier information showed no Phalanx, a Mk38 mod2 on the roof of the hangar, and remote controlled .50s on either side.

      The weapons and fire control systems should be paid for by the Navy.

      • I know a 25-26kt diesel is possible. I just worry that it’s expensive… double the horsepower seems about right.

        Anything that requires a big electric motor is expensive… so CODLAD or (worse) integrated diesel-electric are a bad idea IMHO. A small Power Take-in motor powered by the usual generators should be cheaper (like on the Hollands).

        Glad the Navy has deep pockets… except it doesn’t. As a taxpayer, I’m not OK with adding something like $20 million per hull (times 25!) for marginal missile hard kill capabilities for ships that will spend 95% of their lives puttering around Alaska and the Caribbean. Future provision for CIWS is smart; refurb the 76mm guns and leave it at that. There’s always time for an upgraded Flight II or an MLU if the global situation requires us to turn OPC into a (very shaky) patrol frigate.

    • “- 57mm gun (why not refurb the 76mms?)”

      I suggested this in one of my first posts

      Unfortunately it looks like the Navy does not want to support the support the weapon, which raise the question of what will happen to the 270s which may be around another 20 years.

      Abandoning the 76mm is unfortunate, because a wider selection of rounds is available for it than for the 57mm and the manufacturer is still developing more:

      There are also upgrades to 120 rounds per minute and “stealth” gun houses as well.

      Another alternative is the 5″ Mk45 which is compatible with the fire control system planned for the ships and the Navy is still supporting. There should be enough excess systems are out there, but I doubt the Coast Guard wants to consider the possibility.

    • SLQ-32 ? Oh come on…. please, don’t saddle the WMSM’s with that dinosaur for the next 3 decades ! Besides taking up a lot of space physically inside the ship, it has 2 large antennas topside. Both of which require liquid cooling. What a nightmere to maintain. After you overspend $$$ to buy, install, checkout… then you have the problem of connecting to ____? (whatever combat management system that is selected. Will it be Lockheed Martin again like on the NSC’s ? standby to spend and spend and spend…). And for what ? do the WHEC/WMEC classes even use the SLQ information ? If the CG Washington DC people were smart, they would buy a modern ESM not the band-aided SLQ antiquity, which will cost and cost for countless updates now and forever. Why not just decide (a.) we don’t really need/afford SLQ given the threat, or (b.) get a small, modern one that is one-sixth the size of SLQ, cost’s one-tenth, and provides far more information. Any modern system is more reliable maintenance wise as well as more reliable information wise. Just google ESM systems. Look at what the U.S. Navy might be putting on their modern new warships ? Research DDG-1000 or LCS-1 or LCS-2 or some modern foreign frigates from Germany or Japan. Do something that has foresight. Don’t use hindsight to saddle USCG with ancient SLQ for the next 4o years. If you did some brain usage, you might even be able to buy existing, for-sale, foreign or US manufactured ESM systems that might also perform some (or many ?) of the functions that USCG is putting into SESS/SCIF ?? Perhaps a summer intern at USCG HQ could be assigned to GOOGLE for a week and arrive at 2 or 3 far superior and cheaper systems than SLQ-32. Let the intern use his/her insight, since the WMSM spec’s are certainly devoid of any foresight. Don’t lead us back into the quagmire of endless band-aids applied forever to the obsolete slq-32….

  3. DRC noted, “I can’t understand why the WMSM would need MK38, MK 15, and ROSAM’s. That seems redundant, its more than the WMSL has by alot.”

    I think H_K is on to something, “CIWS doesn’t appear in the GFE list in Schedules B/C, so maybe it’s only a provision for future installation. Smart move.”

    It all makes sense if the ships are to be “fitted for but not with” Phalanx, with the Mk 38 mod2 taking its place until such time as it is fitted. The CONOPS seems to support this. It says “The WMSM will have the ability to install additional equipment to augment its capabilities if it is required to conduct operations in higher threat environments in support of national security objectives.” Additionally the defense readiness scenario, talks about the ship going in for 6 weeks of training and upgrades for point defense and soft kill ASCM (anti-ship cruise missile) protection before being assigned to a surface action group. That is not long enough to make major changes, but certainly long enough to slap on a Phalanx and get some basic training in its use and maintenance, particularly if the wiring and utilities are already in place.

  4. H_K said, “Anything that requires a big electric motor is expensive… so CODLAD or (worse) integrated diesel-electric are a bad idea IMHO. A small Power Take-in motor powered by the usual generators should be cheaper (like on the Hollands).”

    I don’t think this is necessarily true. My evidence is the Lewis and Clark Class. With a length of 689 feet, a beam of 105.6 feet, and a design draft of 29.9 feet), these ships displace 41,000 tons, but their average cost was $442M. They have fully integrated propulsion and ship’s service power plant that uses four Man B&W diesel generators to provide installed power of 35.7MW, more than three times the horsepower of the Holland Class OPVs.

    A well designed integrated system would require fewer crew members for maintenance and watch standing. Since these ships are to be ice strengthened it make sense to avoid design features that may be problematic in the ice, like large twin variable pitch propellers. Electric drive permits fixed pitched propellers. If a strong drop down trainable bow thruster is provided, it might be reasonable to go to a single shaft or azipod which would be less subject to ingesting ice. (Triple screws might be a possibility for a hybrid plant.)

    There is also the case of the Norwegian Coast Guard icebreaking cutter Svalbard. It is powered by four 3390 kW diesel generators and 2 x 5 MW Azipod electric motors, close to the 11 MW of the Holland. Reportedly the 340 foot, 6375 ton ship cost only $80M. My point is that an integrated system does not make the ship prohibitively expensive, and might more than pay for itself in the long run.

    There are some other reason we might want to consider an integrated or hybrid system. Running on electric drive can be much quieter, making the ship both more livable and a better ASW platform. Future weapons and sensors are likely to be energy hogs. Having the ability to generate excess ship’s service power now may be very useful in the future.

    • I seem to recall the last time the Coast Guard went for an innovative – for its time – propulsion system, on the Polar Class icebreaker. Remember how many times they went into the yards for seal failures before they got it right?

      The Lewis and Clark class vessel isn’t designed to operate the way that an OPC will be asked to operate. I’d be careful in drawing conclusions based on that example. Now once someone else fields a frigate-class vessel with an integrated or hybrid electric drive and works out all the kinks, maybe then we should consider it.

      As H_K correctly notes, the days of gold plating a government asset are over.

      • The Lewis and Clarke class may not operate the way the OPCs will be asked to operate, but electric drive ships generally don’t have the critical speed and minimum speed problems other systems are prone to.

        There are already several class of frigates and destroyers with electric drive, and a class of aircraft carriers and a class of big deck amphibs.

        The British built 16 very successful Type 23 “Duke” class frigates from 1990 through 2002. The rationale was both for quiet ASW operations and extended cruising range.

        Their power plant was CODLAG with four 1510 kW (2,025 shp) Paxman Valenta 12CM diesel generators powering two GEC electric motors delivering 2980kW (4000 shp) and two Rolls-Royce Spey SM1A replaced by updated SM1C delivering 23,190 kW (31,100 shp) to two shafts.

        The six ships of the British Type 45 class (8,000 ton destroyers, five ships now complete), use fully integrated electric propulsion (IEP)

        2× Rolls-Royce WR-21 gas turbine generators, 21.5 MW (28,800 shp) each
        2× Wärtsilä 12V200 diesel generators, 2 MW (2,700 shp) each
        2× Converteam electric motors, 20 MW (27,000 shp) each

        The four ships of the German Type 125 class, (7,200 ton “frigates”), building now, are also CODLAG powered with
        1 × 20 MW gas turbine
        2 × 4.7 MW electric motors
        4 × 2.9 MW diesel generators
        3 × gearboxes: one for each shaft and one to cross-connect the gas turbine to them
        2 × shafts, driving controllable pitch propellers
        1 × 1 MW bow thruster

        The new British aircraft carriers are also using an integrated power system. Power is supplied by two Rolls-Royce Marine Trent MT30 36 MW (48,000 hp) gas turbine generator units and four Wärtsilä diesel generator sets (two 9 MW (12,000 hp) and two 11 MW (15,000 hp) sets). The Trents and diesels are the largest ever supplied to the Royal Navy, and together they feed the low-voltage electrical systems as well as the the two tandem electric propulsion motors that drive the twin fixed-pitch propellers.

        The Zumwalt Class (DDG1000) are also being built with an all-electric drive with an integrated power system, (IPS)

        USS America, LHA-6 has a hybrid system using two marine gas turbines, two shafts, 70,000 total brake horsepower and two 5,000 horsepower auxiliary propulsion motors. USS Makin Island, LHD-8, is similar.

        Hybrid should be easy.

        Going back further, during WWII the US built hundreds of electric powered destroyer escorts (frigates) with the power generated by either steam or diesel. Buckley Class (steam turbo-electric), Rudderow (steam turbo-electric), Evert (diesel electric), Cannon Class (diesel electric). Plus the Coast Guard 255s were steam turbo electric.

        Its really not all that unusual. Cutters were built with electric drive in the 20s and 30s. All the WLB 180s were diesel electric. All icebreakers except the Polar class were/are diesel-electric. The 213s, the 205s, the Storis.

        All non-nuclear submarines are diesel electric.

      • If you are talking about diesels generating power that drives an electric motor driving a conventional shaft and screw, you are correct – that isn’t revolutionary, and it is a proven concept. I’m just not sure the azipod drive is something that ought to be selected for the OPC, especially if the OPC is going to be operating in ice.

      • You realize the Icebreaker Mackinaw has Azipods as do lots of recent ice-capable ships.

  5. Chuck, Norway’s Svalbard is interesting. Good find.

    Svalbard’s 10MW electric propulsion cost $17m (NOK 150 million), according to ABB’s website. I doubt this includes the diesels. Subtract the cost of 2 sets of reduction gears, shafts, propellers and thrusters, and add 15 years of inflation. What does that give us as the marginal cost of electric propulsion? $10-15m maybe? And 10MW’s only good enough for 21-22kts… so more like $20-30m extra if you need 25kts.

    Tough call… not sure it’s worth it.

  6. Diesel electric for habor and transit burns very little fuel, you only sprint 10-15 times per year over the life of the ship. a single LM2500 weighs much less than two big diesels, get more horsepower, and requires less maintenance. Any purchase cost increase would be made up in fuel costs.

    Holland class does this now but uses diesels as the sprint to get 22kts. Swap the MDE’s for a turbine and you get the same thing, just faster.

    • A wild guestimate perhaps, but I believe it would require roughly 30,000HP to reach 26 knots (approximately the current output of one LM2500). 15,000 for 22 knots, 7,500 for 18 knots, 3,750 for 14 knots, and less than 2,000 for 10 knots.

      To get to 25 knots from two diesels would probably require that they be larger than those on the NSC (roughly 10,000 HP each), but they would be more than adequate for 22 knots.

      Hamilton class is pretty close, they are 36,000 HP for 29 knots, 18,000 HP to make 22 knots trailing a shaft, and 7,000 for 18 or 19 knots. So the OPC might take a little less to get to 26 knots, but otherwise I think it is close.

      • Chuck, the HP is going to be based on the hull speed and weight. I’m no engineer but my understanding is that the WHEC pushes beyond the hull speed when sprinting. Therefore the extra power beyond ~20kts isn’t very efficient.

        Before we decide on a power plant, let’s lock down that top speed because its going to define the hull size. The ice hardened hull is really going to add weight and pushing through ice is going to require more low end torque, strengthening the argument for the diesel electric tooling/harbor option.

      • Displacement hulls asymptotically approach a limit as the speed over the square of the length in feet approaches 2. As the ship approaches that limit power requirements go up geometrically. That limit is 20 knots for 100 foot waterline length, 30 knots for 225 foot, and 40 knots for 400 foot waterlines. It is why aircraft carriers don’t seem to require that much horsepower to move an awful lot of ship and they can walk away from their escorts. The limit for a 900 foot hull would be 60 knots. It is counter intuitive for those who equate small and fast.

        This does only apply to displacement hulls.

        I’ve found that saying for every four knots the horsepower requirement doubles is a reasonable rough approximation of this effect.

        Of course things like fineness ratios (length to beam) matter. It only works if you compare essentially the same hull shape and size.

  7. Some additional specs I did not mention:
    (1) The OPC hull structure shall be steel (OPC Sys. Spec. Sect. 100.1.2)
    (2) Maximum beam shall be less than or equal to 54 ft. (OPC Sys. Spec. Sect. Table 070-1)
    (3) The projected draft of the cutter shall not exceed 23′-6″ in any loading condition. (OPC Sys. Spec. Sect. Table 070-1)
    (4) Ship shall have fore-and-aft, Port and Starboard, access on weather decks allowing personnel to traverse the length of the ship without use of vertical ladders (inclined ladders are acceptable). (OPC Sys. Spec. Sect.

    The maximum beam is the same as that of the National Security Cutter and the draft is greater, so I would not expect those specs to have much impact on the design.

    The fore and aft, port and starboard weather deck access requirement, could make it impossible to provide a full width helicopter hangar (like the hangar on the FFG-7 class). That might be unnecessarily restrictive.

  8. Chuck, this is a great analysis of the OPC requirements. After being able to tour all the foreign naval ships present at OPSAIL 2012 Norfolk, I envision this ship being something more in line with the development and revitalization seen in the Germanic (German and Danish) and Nordic (Norwegian, Swedish, and Finish) navies. The HDMS Esbern Snare, the FGS Hessen and the HNoMS Thor Heyerdahl were great experiences as they highlighted excellent shipbuilding and technical innovation. If the USCG is smart it will take a similar approach to the OPC as it did with the Webber Class and seek a proven hull type and modify it to its purpose. I would suggest something like the Sigma class corvettes if anyone was asking.

  9. Pingback: An End to ABS Naval Ship Rules | Chuck Hill's CG Blog

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