What Might a Wartime OPC Weapons Fit Look Like?


Four years ago I wrote a post suggesting that the Offshore Patrol Cutter might be designed from the start for a wartime weapons fit, but then fit them out with only those systems required for their peacetime missions, which might have included only its helicopter, UAS, and 25 mm Mk38 Mod2 gun(s).

I started with the assumption that the OPC should be able to mount a weight of weapons at least equal to those mounted on the 255 foot Owasco class cutters as built during World War II (140-150 tons). This figure did not include ammunition other than depth charges, consequently, nearly all the weight was above the main deck. This now appears very conservative in that the Eastern OPC design is about twice the size of the Owasco Class. (For another data point, when built, the USS Fletcher, first of a class of 175 destroyers with a design displacement of 2,700 tons, had 161.8 tons of armaments and 190.8 tons of ammunition.)

In the earlier post, a possible wartime outfit that I believed might be used for designing the ship (and the weights I used) included:

Total 124.4 tons

Since we now have a notional design for the cutter and my own views have changed somewhat, I thought it might be worthwhile to revisit how this class might be armed in wartime. The design may have ruled out some of the systems above, but the surprisingly large size suggest it should be fairly adaptable.

In fact it looks like the OPC could be turned into a credible warship adding only deck mounted systems that require only minimal deck penetration for cabling and the like.

What’s already there?:

Based on earlier information, as built, the design will includes provision for

For a total of 28.55 tons

Anti-Ship Cruise Missile:

LRASM topside launcher concept. The size and weight are comparable to launchers for Harpoon. Photo: Lockheed Martin.
Currently there are three potential anti-ship cruise missiles that might be used, Harpoon, LRASM, and Naval Strike Missile. Harpoon weighs 1,523 lb (691 kg) with a 488 pounds (221 kg) a warhead. Naval Strike missile is smaller, longer ranged, and more intelligence with a weight of 900 lbs (410 kg) with a 276 (125 kg) warhead. LRASM is the newest and supposedly the most “intelligent.”
As I posted earlier, I think the Coast Guard could use a couple of LRASM on each of their NSCs and OPCs even in peacetime as a means of addressing the threat of a terrorist attack using a medium or large ship. It is the missile’s range (about twice the others) and purported ability to target specific parts of a specific target rather than its larger warhead, that made the LRASM the system of choice for this role.
Reportedly the LRASM deck mount is comparable in size and weight to the Mk141, which is the standard quad deck launcher for Harpoon. The only source I could find, indicated that the weight of a quad Mk141 with missiles is 27,126 lbs or 13.6 tons, or 27.2 tons for an eight missile battery. Still I can’t believe the LRSM will not weigh a bit more than Harpoon, seeing its warhead is twice as large. I will assume a quad deck mount weighs about 15 tons, or 30 tons for an eight missile outfit. In any case, if other types of missiles were used, they would weigh less.
These might be positioned either on the fantail or on the platforms aft of the 57mm and below the bridge, one deck above the foc’sle where it appears they plan to mount .50 caliber machineguns possibly in Mk49 ROSAM.

RGM-84 Harpoon SSM was fired from a Mk-141 missile launcher aboard USS Shiloh (CG 67). The Shiloh’s beam is only one foot more than that of the Offshore Patrol Cutter. Looking at the photo, you can see that the launchers take up well under half the width of the fantail.


Photo: Click to enlarge

 Evolved Sea Sparrow Missile:
It appears it may be possible to equip the OPCs with ESSM (Evolved Sea Sparrow Missile). A new version of the missile, the ESSM block II, will obviate the need for illuminators that have been required for earlier versions. These would allow the cutter to provide limited local area AAW protection for ships that the cutter might be escorting out up to 25 miles. Additionally they can be used against surface targets.
Using the Mk56 VLS a loaded 12 missile module weighs 11.5 tons. Physically it is not very large. 3.66 m (12 ft) x 2.71 m (9 ft) x 4.65 m (15’3″) high. We could locate one or perhaps two of these on top of the superstructure where they apparently intend to store the third boat.  This may seem relative high in the ship, but it is the same position where the Oliver Hazard Perry (FFG-7) Class frigates mounted their 76mm gun and the OPC is considerably beamier (54 vis 45 foot).


Photo: Click to enlarge. The relatively small foot print of the Mk56 VLS system (pdf) can be seen here on a Danish Absalon-class command and support ship (beam 64 feet, by comparison the Offshore Patrol Cutters’ beam is 54 feet–same as that of the Bertholf class National Security Cutters).  Two sets are visible in the foreground, one set of twelve with missile canisters with red tops in place to the right, on the ship’s centerline, and a second set of twelve without canisters to the left. The Absalon class has three twelve missile sets, with the third set off camera to the right. 

Photo: 12 earlier Mk48 mod3 VLS for ESSM seen here mounted on the stern of a 450 ton 177 foot Danish StanFlex300 Flyvefisken class patrol boat.  The Mk56 launchers replace the Mk48s with an approximate 20% weight savings. 
This could really be any of three systems, Phalanx, SeaRAM (a modified Phalanx with eleven rolling airframe missiles instead of the 20 mm gun) or the 21 round Mk 49 RAM launcher. Loaded, all three are about 8.5 tons or less.
An operations research study done for Australia “Limitations of Guns as a Defence against Manoeuvring Air Weapons,” (pdf) by Christian Wachsberger, Michael Lucas and Alexander Krstic, Weapons Systems Division, Systems Sciences Laboratory, DSTO-TN-0565 has convinced me that gun systems are unlikely to effective in the future, so for the OPC I would choose two SeaRAM. This has also been chosen for the frigate follow on to the Navy’s LCS.
Two LCS systems could provide automated 360 degree protection against the sudden attack of a coordinated anti-ship missile attack. One system could replace the Mk38 mod2 system currently planned for placement on top of the hangar. A second system could be sited on the superstructure forward and below the bridge, behind and above the 57mm. This might require a small extension of the superstructure to provide a platform sufficiently large enough to both support the system and allow access for maintenance.
AN/SQR-20 Multi-Function Array (Thales CAPTAS 4):
Photo: NavyRecognitionReeling system for the CAPTAS-4 Variable Depth Sonar tether aboard a French Navy FREMM Frigate (Aquitaine class).
If there is a submarine threat, we will need a sonar. Additionally passive towed arrays may be used as a targetting system for anti-ship cruise missiles. In peacetime, a towed array might also be to locate semi-submersibles.
The Thales CAPTAS-4 is one of the systems being considered for the LCS and its frigate derivative. The current version weighs 20.6 tons. The US version will probably be lighter since the Navy is looking for a lighter version for the LCS. Additionally there are lighter options made by Thales and others, so what ever might be chosen is going to be this weight or less. It would of course be mounted on the fantail.

Mk38 mod2/3 and Mk49 ROSAM: 

I will assume that the two Mk49 RO

SAM will be retained and the Mk38 mod2 (or mod3) will be relocated and a second Mk38 (1.15 tons) will be added.


The resulting additions would be:

  • Multi-Function Array (CAPTAS-4) (20.6 tons)
  • MH-60 (11.75 tons)
  • 8 x LRASM (30 tons)
  • 24 x ESSM (23 tons)
  • 2 x SeaRAM (22 missiles) (17 tons)
  • 57mm Mk110 gun w/1000 rounds (15.4 tons)
  • 2 x Mk38 mod2/3 (2.3 tons)
  • 2 x .50 cal. in Mk49 ROSAM (0.25 tons)

This totals 120.3 tons or 91.75 tons more than the planned outfit as built.

We don’t really know if the ship can take this much weight. Assuming it displaces 4,000 tons, which seems likely, this is about a 2.3% increase in displacement and much of the weight is relatively high.

Is it feasible?

There are things that can be done to counterbalance the effects of this additional weight. Some fuel tanks might have to be left permanently full or be converted to ballast tanks. Given the extreme range of the cutter, even half of the design range would be more range than most Navy combatants.

We know the ship is supposed to have some weight moment reservation for additional weapons but we don’t know how much. There is also the requirement that the ship be able to take on, feed and shelter 500 migrants on the foc’sle or flight deck. Those 500 people alone would amount to almost 40 tons of additional top weight.

There are alternatives that could provide a simlar outfit while moving the weight lower. A more extreme change would be to replace both the Mk56 VLS (23 tons) and the 57mm Mk110 (15.4 tons) with Mk41 VLS (33.6 tons) in place of the 57mm. We would loose the gun, but this would provide the additional capability of launching Anti-Submarine Rockets (ASROC) as well. That might be a good trade, but it would require more radical reconstruction.

In short, adding less weight in weapons than carried by the 255 foot Owasco Class cutters of WWII, the Offshore Patrol Cutter could be turned into an effect surface combatant comparable to many frigates. The same sort of alterations could also be appied to the National Security Cutters.

New Dual Fuel Finnish Icebreaker


MarineLog reports the delivery of the world’s first Icebreaker capable of running on LNG. It does appear that its capabilities using LNG alone may be limited. “The diesel-electric propulsion system includes two Wartsila 6,000 kW engines and one 1,280 kW dual fuel engine.” If, as it appears, only the 1,280 kW engine can use LNG.

I found the size of the Finnish icebreaker fleet interesting.

“Following delivery, the Finnish Transport Agency handed the vessel over to Arctia Icebreaking Oy, A Finnish state-owned company that operates a fleet of vessels that provide icebreaking services. Besides the Polaris, Arctia Icebreaking Oy operates three multipurpose icebreakers, one oil spill recovery icebreaker, three 113-ton bollard pull icebreakers, and one harbor icebreaker and towing vessel. The newest oceangoing icebreakers in the fleet, the Fennica and Nordica—two 230-ton bollard pull icebreakers—were both delivered in 1993.”

Note, the range and endurance required of these icebreakers is closer to what we think of as domestic icebreakers rather than polar icebreakers, but still an impressive fleet.

Late addition: gCaptain has a more complete description of the ship: http://gcaptain.com/arctech-helsinki-delivers-worlds-first-lng-powered-icebreaker-finnish-government/

Man Overboard Alarm

Photo: ALERT2 Man-Overboard Alarm System from Emerald Marine Products 

Loosing a man overboard is one of those nightmares you never want happening on your watch. I was CG liaison officer at Fleet Training Group San Diego when a 210 that had recently lost two men over board came through for REFTRA. Four crewmen, being good sailors, took it upon themselves to go on deck during a storm to secure some loose equipment. All four were washed overboard. The sea then deposited two of them back on board. The other two were never found, so it does happen.

MarineLink has a story about a device that alarms the watch when its wearer goes in the water.

“Upon receiving an MOB activation signal, the AR100 Receiver sets off a loud, 95 dB alarm and bright red alert light on the display. It can be wired to shut down engines—essential for solo mariners and fishermen. Connected to a compatible GPS chartplotter, it automatically sets an overboard waypoint. External speakers and strobes can be utilized with the AR100. It can also be configured to alert via a remote cellular dial-up, radio transmission burst or Internet-connected device. The AR100 Receiver runs on 12V, or on 110V using the optional power supply. It comes with a flexible whip antenna, coaxial cable and full mounting hardware.

“The optional ALERT2 Portable Directional Finder aids crew in locating the MOB when visual contact is lost due to darkness or sea conditions. Unlike AIS, which is typically installed in the wheelhouse, the directional finder can be used on deck. Rescuers sweep the horizon to quickly home-in on the transmitter’s signal for a fast recovery.

“Emerald Marine Products’ ALERT2 AT101 Transmitter lists for $269, the AT200 IS model for $369, the AR100 Receiver for $749 and the Portable Directional Finder for $899. Discounted pricing is available for packages.”

Note, I don’t really know if this a good company or its products are the best of the type, so I’m not endorsing the particular product, but simply pointing out that such things exist. Maybe the Coast Guard is already using them. I know I would feel better, if I knew my BMOW was wearing a device with the capability claimed for these.

Indonesian Bomb Plot?


Photo: Floor-by-floor breakdown of the injuries/deaths in the Alfred P. Murrah Federal Building from the April 1995 Oklahoma City bombing. Red triangles indicates a fatality, a yellow one indicates a victim was admitted. Author: Sue Mallonee at Oklahoma State Department of Health Injury Prevention Service

gCaptain is reporting that Indonesian authorities on the resort island of Bali have detained a ship from Malaysia carrying around 30 tonnes of ammonium nitrate which police believe may have been intended for making bombs.

Ammonium nitrate was, you may recall, a primary igrediant in the truck bomb used in the attack on the Murrah Federal Building in Oklahoma City in 1995.

“…the bombing destroyed one-third of the building, killed 168 people, and injured more than 680 others. The blast destroyed or damaged 324 other buildings within a 16-block radius, shattered glass in 258 nearby buildings, and destroyed or burned 86 cars, causing an estimated $652 million worth of damage.”

Total weight of the explosives in that case was perhaps 7.000 pounds or less.

There is no indication that the ship itself was intended to be used as a bomb delivery system.

Bell V-247 Vigilant tiltrotor–The Eagle Eye Look-a-Like


Photo: V-247 Vigilant, Bell Helicopter artist rendering

Earlier we talked about the possibility of a new tilt-rotor UAS with a configuration similar to the Eagle Eye concept that was part of the original DeepWater program. Now we have a Bell Helicopter news release which provides more information on this program and its capabilities, plus a designation, V-247, and a name, Vigilant.” A Breaking Defense post puts the program in context relative to the V-22, the Marines intended use, and the Air Force’s long endurance MQ-9 Reaper UAS.

As noted earlier, this is a much larger aircraft than the Eagle Eye would have been. Bell states that its wing and rotor folded foot print is equivilent to that of a UH-1Y (latest version of the Huey) which is much larger than an MH-65 and only slightly smaller than an H-60. It uses a single 6,000 HP engine. If deployed on a cutter it would replace a manned helicopter.

Below is the Bell news release quoted in full:

FORT WORTH, Texas (Sept. 22, 2016) – Speaking before an audience of aviation and military experts assembled at the National Press Club in Washington, D.C., Bell Helicopter, a Textron Inc. (NYSE: TXT) company, today unveiled the Bell V-247 Vigilant tiltrotor.

To download renderings of the Bell V-247 Vigilant tiltrotor, please follow this link.

The Bell V-247 tiltrotor is an unmanned aerial system (UAS) that will combine the vertical lift capability of a helicopter with the speed and range of a conventional fixed-wing aircraft.  The revolutionary UAS is designed to provide unmatched long-endurance persistent expeditionary and surveillance capability and lethal reach, as well as runway independence to operate successfully in maritime environments and locations without secure runway availability.

The Bell V-247 Vigilant satisfies the comprehensive spectrum of capabilities outlined in the 2016 Marine Corps Aviation Plan, and could be available for production as early as 2023. The Bell V-247 Vigilant is a solution designed to address the evolving demands of the military and transportation sectors for unmanned aircraft for a shipborne UAS platform, including:

  • The ability to operate successfully without a runway, such as in maritime environments
  • Seamless performance in locations without secure runway availability, such as at shrinking land bases in contested areas
  • Significant reduction of the logistical footprint while retaining the superior operational performance by combining the vertical lift capability of a helicopter with the speed and range of a conventional fixed-wing aircraft
  • The capacity to control the battle space effectively with 24-hour intelligence provided by unmatched long-endurance persistent expeditionary and surveillance capability

A Group 5 UAS, the Bell V-247 Vigilant is designed to combine unparalleled capability with unprecedented flexibility to execute a wide array of mission sets, including electronic warfare, ISR (Intelligence, Surveillance and Reconnaissance), escort, C4 (Command, Control, Communications, and Computers), persistent fire missions and tactical distribution. The UAS is expected to accomplish all of this with the benefits of extended endurance through plug-and-play mission packages.

“The Bell V-247 Vigilant is the next leap in innovation making the future of aviation a reality today – it’s a testament to the power and versatility of tiltrotor flight,” said Mitch Snyder, president and CEO at Bell Helicopter. “At Bell Helicopter, we are constantly challenging the traditional notion of what it means to fly by staying on the leading edge of aviation and technological development. The unmanned tiltrotor is the latest example of how we are changing the way the world flies, taking our customers into the dynamic world of next-generation aircraft.”

The Bell V-247 Vigilant’s design boasts a number of unrivaled capabilities and transformational features, including:

  • A sea-based platform, which can be sized for compatibility with DDG guided missile destroyers shipboard applications
  • Single engine tiltrotor unmanned aerial system
  • 24-hour persistent ISR with a two aircraft system
  • Speed: 250 knots cruise speed; 180 knots endurance speed; >300 knots at maximum continuous power
  • Combat range: 450 nautical miles mission radius
  • Time on station: 11 hours
  • Size: 16,000 pounds empty weight / 29,500 pounds max gross weight; 65-feet wing span; 30-feet rotor diameter
  • As it sits on the deck, the V-247 Vigilant can hold a combination of fuel, armament, and sensors, up to 13,000 pounds
  • Blade Fold Wing Stow makes V-247 Vigilant DDG hangar compatible
  • Expeditionary capability with small logistical footprint
  • Open architecture and interfaces
  • Air-to-air refueling
  • Modular payload system to provide maximum flexibility
  • Power distribution system to provide maximum mission capability
  • Redundant flight control system
  • Electro Optical System and Targeting System

The Bell V-247 Vigilant offers a dynamic profile that is uniquely suited to complete highly versatile operations and support missions. It is designed to provide extended range flying from land or ship, matchless expeditionary capabilities and to remain on-station with heightened loiter times for extended periods. With its signature blade fold wing stow design, it will fit inside a DDG hangar space, and two can be loaded on a C-17 aircraft. The open architecture of the modular payload system enhances flexibility for aircraft customization by mission type. The bays on the Bell V-247 Vigilant are designed to carry high definition sensors, fuel, sonar buoys, light detection and ranging (LiDAR) modules, 360-degree surface radar modules, an MK-50 torpedo or Hellfire or JAGM missiles optimally. Regardless of the need, the Bell V-247 Vigilant easily integrates into priority mission sets to complete multiple airborne requirements.

“Leveraging lessons learned from our extensive history and experience with tiltrotors, we have found the best available solution to fulfill the Marine Corps need for a Group 5 UAS,” said Vince Tobin, vice president, advanced tiltrotor systems at Bell Helicopter. “The Bell V-247 Vigilant will give military customers the capabilities needed to reduce the complexity of deployment, increase speed of employment, reduce mission times and increase response time – all critical elements to completing missions to save lives and protect our freedom.”

Bell Helicopter utilized its decades of applied tiltrotor experience to develop this next generation UAS. The Bell V-247 Vigilant design and capabilities bring to bear experience from the V-22 tiltrotor program and UH-1Y/AH-1Z programs, capturing the V-280 Valor’s unmatched design and performance standards in order to provide unparalleled competency to support ship-board compatibility.

Press Contact:
+1 817-280-3100

What Does It Take to Sink a Ship–the ex-USS Rentz Sink-Ex

Earlier I explored “What Does It take to Sink a Ship?” as a measure of what it takes to be absolutely sure you can stop one. Then the Japanese Tsunami gave us fishing vessel Ryou-Un Maru, a small vessel USCGC Anacapa attempted to sink with their 25mm gun. Anacapa ultimately resorted to coming along side and using a fire hose to fill the vessel with water, but it took over five hours.

Now the Navy provides us with information about another Sink-Ex. The former USS Rentz (FFG-46), a 4,200 ton, 453 foot long frigate, was the target. In spite of being hit by 22 missiles, she took five hours to sink. The last hit or hits were by Hellfire, and may not have been necessary, but not all the missiles were that small. The caption below appears to indicate at least two Harpoons were used.


Photo: US Navy. Guided-missile destroyer USS Benfold (DDG 65), foreground, and USS John S. McCain (DDG 56) fire Harpoons missiles as part of a sink exercise (SINKEX) during Valiant Shield 2016.

Reports also indicate that at least one JSOW C-1, an over 1000 pound guided gliding munition with both Infra-Red and Link-16 guidance, was used.

The caption on the photo below seems to indicate multiple AGM-65F were used. These are infra-red homing, Air to Surface Missiles, weighing over 600 pounds with a 300 pound warhead.

U.S. Navy sailors with Patrol Squadron 46 load a P-3 Orion aircraft with AGM-65F MAVERICKS Air to Surface Missiles prior to a sinking exercise (SINKEX) Sept. 13, 2016, at Andersen Air Force Base, Guam, during Valiant Shield 2016. SINKEX provided service members the opportunity to gain proficiency in tactics, targeting, and live firing against a surface target at sea. Valiant Shield is a biennial, U.S. -only field-training exercise with a focus on integration of joint training among U.S. forces. (U.S. Marine Corps photo by Sgt. Justin Fisher)

U.S. Navy sailors with Patrol Squadron 46 load a P-3 Orion aircraft with AGM-65F MAVERICKs, prior to a sinking exercise (SINKEX) Sept. 13, 2016, at Andersen Air Force Base, Guam, during Valiant Shield 2016.

When the video at the head of this post begins, it appears that the ship has already taken at least three major hits. I suspect these were two Harpoons and possibly the JSOW C-1. I suspect the four hits seen in the video were Mavericks launched from the P-8 that made the video.

The video below shows a Hellfire hitting what appears to be an already sinking hulk. It appears to me, the effects are clearly less than those seen in the video at the top of the post.

I would love to have a clearer idea of the sequence and effects of the individual hits, but one thing is clear. It took a lot of ordnance to put even this relatively small ship down. The Coast Guard’s 25 mm and 57 mm guns, with their five ounce and six pound projectiles, will not cut it.

OPC–Eastern Wins the Contract


The second photo is a more recent concept rendering

The Coast Guard’s Acquisitions Directorate (CG-9) is reporting Eastern Shipbuilding Group has been awarded the contract for detail design and construction of the first of 25 Offshore Patrol Cutters (OPC) expected to replace the Coast Guard’s overage Medium Endurance Cutter Fleet.

“The Coast Guard today selected Eastern Shipbuilding Group Inc. of Panama City, Florida, to continue to the detail design and construction phase (Phase II) of the offshore patrol cutter acquisition program. The award is worth $110.29 million.

“The full Phase II award covers detail design and production of up to nine OPCs and has a potential value of $2.38 billion if all options are exercised.

Eastern Shipbuilding Group’s notional design is 360 feet long, with a beam of 54 feet and a draft of 17 feet. The OPCs will have a sustained speed of 22.5 knots, a range of 10,200 nautical miles (at 14 knots), and an endurance of 60-days. It is expected to “conduct missions including law enforcement, drug and migrant interdiction search and rescue, and other homeland security and defense operations. Each OPC will feature a flight deck and advanced command, control, communications, computers, intelligence, surveillance and reconnaissance equipment.” It’s hangar will accommodate one MH-60 or an MH-65 and a Unmanned Air System (UAS).

There are nice side and plan views of the design and a summary of its characteristics here (pdf).

WJHG.com reports, “At a cost of around $484 million per ship, it’s the largest contract the Coast Guard has ever awarded in its 226-year history.”

I’m not sure how that works out because “production of up to nine OPCs and has a potential value of $2.38 billion if all options are exercised” equals $264.4M/ship. If that is the actual shipyard building costs and the remaining $220M is Government Furnished Equipment (GFE) and other costs the ships may be a real bargain.

Hopefully additional details of the design will surface in the near future.

Thanks to Luke for bring this to my attention.