Just ran across a manufacturer’s web page that I thought might be interesting as an example of what can be accomplished in terms of arming smaller vessels. It is not the missiles so much as the launchers I found interesting.
These are two systems from Rafael. Rafael is the designer of the Typhoon gun mount we know as the Mk38 Mod2/3 being installed on the Webber Class WPCs and planned as the secondary weapon for the Offshore Patrol Cutter.
The first of these is the Typhoon MLS-ER (Missile Launch System–Extended Range) seen in the illustration above. The system includes the 8 km range Spike ER missile and reportedly can be installed on vessels as small as RHIBs. It is similar to Hellfire in capability, except that it has the potential advantage of providing for a man in the loop who can retarget or abort after launch.
You can see what appears to be a four round launcher mounted aft on the aft superstructure. The boat seen in the photograph is, I believe, a Super Dvora III. These boats are slightly longer than the Coast Guard 87 foot Marine Protector class WPBs, but are lighter displacement.The description of this boat says that they are armed with the Typhoon gun mount, Spike ER, and Hellfire. This makes me wonder if the missile launcher can launch Hellfire as well as Spike ER.
You can see the Spike ER, as well as the 25 mm gun in the Mk38, in operation in the video below.
Below is the Wikipedia description of the Spike-ER
Extended range or extra-long range version of the weapon. It was formerly also known as the NT-Dandy or NT-D. It has a minimum range of 400 m and a maximum range of 8,000 m (5.0 mi). It has a larger diameter and is heavier than the other (older Spike missile–Chuck) systems, and is usually vehicle mounted. It is used by infantry, Light Combat Vehicle (LCVs), and helicopters. The Finnish Navy’s Coastal Jaegers also operate the version in the anti-ship role. The weight of the missile is 34 kg (74 lb 15 oz), the launchers are 30 kg (66 lb 2 oz) and 55 kg (121 lb 4 oz) respectively for the vehicle and air-launched versions. Penetration is around 1,000 mm (39 in) of RHA (Rolled Homogenous Armor–Chuck).
TYPHOON MLS NLOS has an eight cell Spike NLOS missile launcher and integrated Toplite stabilized observation and target acquisition system (same as on the Mk38 mod2). Photo: RAFAEL via defense-update.com
The Toplite is the same Electro-optic system mounted on our Mk38 mod2 gun mounts. The missile itself is about 50% larger than a Hellfire. The Wikipedia description is quoted below.
“Non Line Of Sight” is an ultra long-range version of the weapon, with a claimed maximum range of 25 km (16 mi). It is a significantly larger missile than other Spike variants, with an overall weight of around 70 kg (154 lb 5 oz). It can be launched from the ground or from helicopters. It was developed following lessons learned in the Yom Kippur War, which showed a need for a high-precision guided tactical ground-to-ground battlefield missile. Codenamed Tamuz (תמוז), the first variants entered service with the IDF in tandem with the Pereh missile carrier in 1981, though the existence of both was not revealed to the public until 2011. The Spike NLOS uses a fiber optic link similar to other Spike versions, but only out to 8 km, after which it employs a radio data link for command guidance.
In 2011 it also became known that in a highly unusual move, the British Army was hastily equipped with the missile, drawn directly from IDF inventory after being exposed to increasing insurgent attacks in Iraq and Afghanistan beginning in 2007. The UK initially acquired 600 missiles, which it designated EXACTOR-1 in British service, later procuring a more advanced variant designated EXACTOR-2. In a deal concluded on 6 September 2011, the South Korean government had agreed to purchase an unknown number of Spike NLOS missiles.
Rafael is working on expanding the missile’s versatility by enhancing the existing EO-IR/CCD seeker with semi-active laser (SAL) capability and different anti-armor, blast-penetration, and high-explosive fragmentation warheads to meet specific applications.
While I started this post to talk about the missile systems, it seemed the Super Dvora III also has features worth discussing.
This boat is very similar in size to the Marine Protector Class WPBs. Dimensions are 90×18.6×3.6 feet for the Israeli and 87×19.4×5.6 feet for the WPB. The all aluminum construction of the Israeli boat has yielded much lighter displacement, ranging from 58 to 72 tons full load for the Israeli boat compared to 91 tons for the WPB. The lighter displacement would presumably result in both higher speed and lower fuel consumption. I am hoping the next WPB will be composite construction on the assumption that that would combine these advantages with corrosion resistance and lower maintenance.
The Israeli boat initially used an articulated surface drive but switched to a water jet. Both allowed these boats to operate in very shallow water. The Israeli boat is also much faster than the WPB (45 knots compared to 25 knots) for a relatively modest increase in power. (4,175 v 2,950 HP).
The Super Dvora Mk III’s weapons can be slaved to a mast-mounted, day/night, long range electro-optic systems. We will probably want such a system on our next WPB. It could aid in SAR, Law Enforcement, and navigation as well as weapons control.
The Israeli boat does not have a stern boat ramp and may not be as sea worthy as the WPB, but WPBs really are our “fast response cutters” so dash speed is a significant characteristic. I would expect the next WPB to be larger, faster, and better armed. If it could also operate in shallower water than our current WPBs that would also be desirable.
Fire damage, USCGC Brant (WPB-87348), Gulfport, MS, 18 Oct., 2017. Looking at the aft port corner of the superstructure.
The 87 foot WPB USCGC Brant (WPC-87348) has suffered a fire while berthed in Gulfport MS. Two were aboard, but there were no injuries.
This is the CCGD8 news release:
NEW ORLEANS – Members from Gulfport Fire Department and a Coast Guard member extinguished a fire aboard Coast Guard Cutter Brant, which was moored in Gulfport, Mississippi, Wednesday.
At approximately 5 a.m., two Coast Guard members who were aboard the cutter became aware of the fire, located on the port-aft area of the vessel, and took initial actions to put out the fire using an on board fire extinguisher.
Members from Gulfport Fire Department arrived on scene at 5:05 a.m. and extinguished the fire.
The two Coast Guard members on board the vessel were evaluated by emergency medical services and have been released.
“We are thankful no one was hurt in the fire,” said Cmdr. Zachary Ford, the head of the response department at Coast Guard Sector New Orleans. “Without the quick response and actions taken by the Gulfport Fire Department, this incident could have been much worse.”
The cause of the incident is under investigation.
Below is a photo of a sister ship, USCGC Crocodile. I understand this started as an electrical fire in the engineroom.
USCGC Crocodile. the area of damage is clearly visible to the left of the ladder leading to the bridge. Damage seems to have been in a trunk leading down to the engine room. There may have been additional damage below deck.
The Navy has been talking a lot about distributed lethality lately, and “if it floats, it fights.” There is even talk of mounting cruise missiles on Military Sealift Command (MSC) ships, even though it might compromise their primary mission. But so far there has been little or no discussion of extending this initiative to include the Coast Guard. The Navy should consider investing high-end warfighting capability in the Coast Guard to augment existing force structure and provide a force multiplier in times of conflict. A more capable Coast Guard will also be better able to defend the nation from asymmetrical threats.
Why Include the Coast Guard?
A future conflict may not be limited to a single adversary. We may be fighting another world war, against a coalition, perhaps both China and Russia, with possible side shows in Africa, the Near East, South Asia, and/or Latin America. If so, we are going to need numbers. The Navy has quality, but it does not have numbers. Count all the Navy CGs, DDGs, LCSs, PCs and PBs and other patrol boats and it totals a little over a hundred. The Coast Guard currently has over 40 patrol ships over 1,000 tons and over 110 patrol craft. The current modernization program of record will provide at least 33 large cutters, and 58 patrol craft of 353 tons, in addition to 73 patrol boats of 91 tons currently in the fleet, a total of 164 units. Very few of our allies have a fleet of similar size.
Coast Guard vessels routinely operate with U.S. Navy vessels. The ships have common equipment and their crews share common training. The U.S. Navy has no closer ally. Because of their extremely long range, cutters can operate for extended periods in remote theaters where there are few or even no underway replenishment assets. The Coast Guard also operates in places the USN does not. For example, how often do Navy surface ships go into the Arctic? The Coast Guard operates there routinely. Virtually all the U.S. vessels operating with the Fourth Fleet are Coast Guard. There are also no U.S. Navy surface warships home based north of the Chesapeake Bay in the Atlantic, none between San Diego and Puget Sound in the Pacific, and none in the Gulf of Mexico with the exception of mine warfare ships.
In the initial phase of a conflict, there will be need to round-up all the adversaries’ merchant ships and keep them from doing mischief. Otherwise they might lay mines, scout for or resupply submarines, put agents ashore, or even launch cruise missiles from containers. This is not the kind of work we want DDGs doing. It is exactly the type of work appropriate for Coast Guard cutters. Coast Guard ships enjoy a relatively low profile. Unlike a Carrier Strike Group or Navy SAG, they are less likely to be tracked by an adversary.
If we fight China in ten to twenty years, the conflict will likely open with China enjoying local superiority in the Western Pacific and perhaps in the Pacific in general. If we fight both China and Russia it may be too close to call.
The National Security Cutter (NSC)
This class of at least nine and possibly ten, 418 foot long, CODAG powered, 28 knot ships, at 4,500 tons full load, are slightly larger than Perry-class frigates. Additionally they have a 12,000 nautical mile cruising range. As built they are already equipped with:
Navy certified helicopter facilities and hangar space to support two H-60 helicopters,
A 57 mm Mk110 gun,
SPQ-9B Fire Control Radar
Phalanx 20mm Close in Weapon System (CIWS)
2 SRBOC/ 2 x NULKA countermeasures chaff/rapid decoy launcher,
A Sensitive Compartmented Intelligence Facility (SCIF)
In short, they are already equipped with virtually everything needed for a missile armed combatant except the specific missile related equipment. They are in many respects superior to the Littoral Combat Ships. Adding Cooperative Engagement Capability might even allow a Mk41 equipped cutter to effectively launch Standard missiles targeted by a third party.
The ships were designed to accept 12 Mk56 VLS which launch only the Evolved Sea Sparrow missiles (ESSM). Additionally, the builder, Huntington Ingalls, has shown versions of the class equipped with eight Mk41 VLS (located between the gun and superstructure) plus eight Harpoon, and Mk32 torpedo tubes (located on the stern). Adding missiles to the existing hulls should not be too difficult.
The Mk41 VLS are more flexible in that they can accommodate cruise missiles, rocket boosted antisubmarine torpedoes (ASROC), Standard missiles, or Evolved Sea Sparrow missiles (ESSM). Using the Mk41 VLS would allow a mix of cruise missiles and ESSM with four ESSMs replacing each cruise missile, for example eight cells could contain four cruise missiles and 16 ESSM, since ESSM can be “quad packed” by placing four missiles in each cell. Development of an active homing ESSM is expected to obviate the need for illuminating radars that are required for the semi-active homing missiles. Still, simpler deck mounted launchers might actually offer some advantages, in addition to their lower installation cost, at least in peacetime.
Cutters often visit ports where the population is sensitive to a history of U.S. interference in their internal affairs. In some cases, Coast Guard cutters are welcome, while U.S. Navy ships are not. For this reason, we might want to make it easy for even a casual observer to know that the cutter is not armed with powerful offensive weapons. Deck mounted launchers can provide this assurance, in that it is immediately obvious if missile canisters are, or are not, mounted. The pictures below show potential VLS to be considered.
The Offshore Patrol Cutter (OPC)
The OPC program of record for provides 25 of these ships. A contract has been awarded to Eastern Shipbuilding Group for detail design and construction of the first ship, with options for eight more. The 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’s hangar will accommodate one MH-60 or an MH-65 and an Unmanned Air System (UAS).
Notional design characteristics and performance of the OPC. (USCG Image)
It will have a space for a SCIF but it is not expected to be initially installed. As built, it will have a Mk38 stabilized 25 mm gun in lieu of the Phalanx carried by the NSC. Otherwise, the Offshore Patrol Cutter will be equipped similarly to the National Security Cutter. It will likely have the same Lockheed Martin COMBATSS-21 combat management system as the LCS derived frigates. It is likely they could be fitted with cruise missiles and possibly Mk56 VLS for ESSM as well. Additionally these ships will be ice strengthened, allowing the possibility of taking surface launched cruise missiles into the Arctic
The Fast Response Cutter (FRC)
The FRC program of record is to build 58 of these 158 foot, 28 knot, 365 ton vessels. 19 have been delivered and they are being built at a rate of four to six per year. All 58 are now either built, building, contracted, or optioned. They are essentially the same displacement as the Cyclone class PCs albeit a little slower, but with better seakeeping and a longer range. Even these small ships have a range of 2,950 nm. They are armed with Mk 38 mod2 25 mm guns and four .50 caliber M2 machine guns.
The first Sentinel-class Fast Response Cutter (FRC), USCGC Bernard C. Webber. (USCG photo)
They are already better equipped than the Coast Guard 82 foot patrol boats that were used for interdiction of covert coastal traffic during the Vietnam war. If they were to be used to enforce a blockade against larger vessels, they would need weapons that could forcibly stop medium to large vessels.
The Marine Protector Class
There are 73 of these 87 foot, 91 ton, 26 knot patrol boats. Four were funded by the Navy and provide force protectionservices for Submarines transiting on the surface in and out of King Bay, GA and Bangor, WA.
If use of these vessels for force protection were to be expanded to a more hostile environment, they would likely need more than the two .50 caliber M2 machine guns currently carried. The four currently assigned to force protection units are currently equipped with an additional stabilized remote weapon station.
The U.S. Navy currently has or is considering four different surface launched cruise missiles: Harpoon, Naval Strike Missile (NSM), Long Range Anti-Ship Missile (LRASM), and Tomahawk. Of these, LRASM appears most promising for Coast Guard use. Tomahawk is the largest of the four and both Harpoon and NSM would be workable, but they do not have the range of LRASM. The intelligence and range claimed for the LRASM not only makes it deadlier in wartime, it also means only a couple of these missiles on each of the Coast Guard’s largest cutters would allow the Coast Guard’s small, but widely distributed force to rapidly and effectively respond to asymmetric threats over virtually the entire U.S. coast as well as compliment the U.S. Navy’s efforts to complicate the calculus of a near-peer adversary abroad
Small Precision Guided Weapons
It is not unlikely that Fast Response Cutters will replace the six 110 foot patrol boats currently based in Bahrain. If cutters are to be placed in an area where they face a swarming threat they will need the same types of weapons carried or planned for Navy combatants to address this threat. These might include the Sea Griffin used on Navy’s Cyclone-class PCs or Longbow Hellfires planned for the LCS.
Additionally, a small number of these missiles on Coast Guard patrol craft would enhance their ability to deal with small, fast, highly maneuverable threats along the U.S. coast and elsewhere
Light Weight Anti-Surface Torpedoes
If Coast Guard units, particularly smaller ones, were required to forcibly stop potentially hostile merchant ships for the purposes of a blockade, quarantine, embargo, etc. they would need something more that the guns currently installed.
The U.S. does not currently have a light weight anti-surface torpedo capable of targeting a ship’s propellers, but with Elon Musk building a battery factory that will double the worlds current capacity and cars that out accelerate Farraris, building a modern electric small anti-surface torpedo should be easy and relatively inexpensive.
Assuming they have the same attributes of ASW torpedoes, at about 500 pounds these weapons take up relatively little space. Such a torpedo would also allow small Coast Guard units to remain relevant against a variety of threats.
Adding cruise missile to the Coast Guard National Security Cutters and Offshore Patrol Cutters would increase the number of cruise missile-equipped U.S .surface ships by about 40 percent.
Coast Guard Patrol craft (WPCs) and patrol boats (WPBs) significantly outnumber their Navy counterparts. They could significantly increase the capability to deal with interdiction of covert coastal traffic, act as a force multiplier in conventional conflict, and allow larger USN ships to focus on high-end threats provided they are properly equipped to deal with the threats. More effective, longer ranged, and particularly more precise weapons could also improve the Coast Guard’s ability to do it Homeland security mission.
Thanks to OS2 Michael A. Milburn for starting the conversation that lead to this article.
Regarding the deployment of WPBs the study noted, “Even though the Coast Guard served a similar mission in Vietnam, there existed no operational plan to provide guidance for OIF planning and preparations.”
If the Coast Guard does not yet have a contingency plan for deployment of patrol vessels there is enough detail to make a fair start on a checklist of things to be done. The experience of the WPBs deployed to the Mediterranean can leave little doubt of the Webber Class’ ability to go almost anywhere, given time to avoid bad weather.
“On May 14, the five cutters (one 378 and four 110s–Chuck) began the return trip; however, this time the smaller cutters followed Dallas across the Atlantic rather than riding on board an MSC vessel. The 5,000-mile voyage set a record as the longest transit ever completed by a 110-foot cutter. The PATFORMED fleet had performed its escort and MIO mission admirably. Moreover, the WPBs in the Mediterranean and the Arabian Gulf had set records for hours of operation with some of them deploying for over thirty days of operation.”
For the future, there might be some advantage in organizing at least a few of the Webber class in deployable divisions (3 units) and squadrons (six units) as discussed earlier, with or without augmentation since there will be several location with three or more WPCs.
The FY2015 budget provides for decommissioning eight 110s.
The Coast Guard plans on 58 Webber class, so presumably they would want to retain enough 110s to provide a total of 58 larger patrol craft with the 110s filling in until replaced by the new ships. It does not look like this will happen. Since the decommissioning of eight Island class as a result of the failure of the 123 conversion, there have been 41 Island class WPBs. Adding the Webber class WPCs currently commissioned that gives the Coast Guard a total of 49 large patrol craft. It appears the total will not exceed 49 at any time in the foreseeable future.
If 110s are decommissioned at the same rate Webber class are built, the number may stabilize at 49. If on the other hand the Coast Guard is unable to keep these older vessels going, the total is likely to drop. If that happen, as little as I like the idea of multiple crews, perhaps it is time to look at multi-crewing the Webber Class. .
Unfortunately there are many stories of Naval battles during WWII when it seems we forgot to look for survivors after the battle. Fortunately President Roosevelt insisted that Coast Guard boats be sent to accompany the invasion fleet for the Normandy invasion. There were 60 of the wooden hulled gasoline powered boats sent England for the invasion.
Despite their apparent vulnerability, I have never heard of one being lost to enemy action. There were 15 Coast Guardsmen killed at Normandy on June 6, 1944. None were aboard the 83 footers. 11 were on the three Coast Guard manned LCI(L)s, Landing Craft Infantry (Large), that were lost that day: Coast Guardsmen killed in action on D-Day.
Photo: No date listed; probably June 1944. No photo number. Photographer unknown.
Apparently, with the target rich environment the Germans were presented, they concentrated on the vessels bringing troops ashore and the shore bombardment vessels that were shooting at them.
When we consider how our cutters might be used in future conflicts we might keep this experience in mind.
MarineLog reports that Damen has secured a contract with the government of the Bahamas.
“It covers the acquisition of nine vessels for the Royal Bahamas Defence Force and construction work for their naval bases plus additional dredging works to accomodate new long range patrol craft.”
The nine vessels are in three class. One, a “San Lander 5612,” is a small ro/ro much like the old LCUs, intended for disaster response. Four will be a version of Damen’s, Stan Patrol 4207, 42 meter patrol boats, which includes the Canadian patrol boats we discussed earlier, that are closely related to the Coast Guard’s own Fast Response Cutter.
What I found particularly interesting were the four smaller patrol boats with a Damen developed “axe bow” because they may give us a glimpse at the future replacement for the 87 foot “Marine Protecctor” class WPBs (27 meters long, 6 meter beam), which was also a Damen design. Its designation, SPa 3007, indicates it is 30 meters long and a 7 meter beam (98.4 ft long, 23 ft beam).
Just a short note to highlight the existence of a couple of unusual units that may not be familiar. They have an important, if largely unrecognized mission. These are the Coast Guard’s Maritime Force Protection Units Bangor, WA and Kings Bay, GA.
The units are perhaps unique in that they have only a single mission, and they are funded by the Navy. They protect Fleet Ballistic Missile submarines while they transit on the surface, to and from their homeports. The possibility of a USS Cole style attack motivated their creation. Each unit consist of approximately 200 Coasties and is commanded by an O-5. Having CG crews and carrying CG colors and markings allows them to enforce a security zone around the subs. Both units stood up in July 2007.
They have some unique equipment too, including four 87 footers that were purchased with Navy funds. They are recognizable because of the stabilized remotely controlled machine guns mounted high on the bow.
SEA DRAGON WPB 87367 Delivered NOV 2007 Kings Bay, GA
SEA DEVIL WPB 87368 Delivered Feb 2008 Bangor, WA
SEA DOG WPB 87373 Delivered April 2009 Kings Bay, GA
SEA FOX WPB 87374 Delivered May 2009 Bangor, WA
Photo Credit: KEYPORT, Wash. (Aug. 18, 2009) U. S. Coast Guardsmen man the rails as the U.S. Coast Guard Cutter Sea Fox (WPB 87374) is brought to life at Naval Base Kitsap. (U.S. Navy photo Ray Narimatsu/Released)
The names chosen for these Navy purchased vessels all reprise submarines that fought in WWII. A contemporary report on the arrival of Sea Devil indicates these 87 footers are manned differently as well,
“To carry out its new mission, the Sea Devil carries more crew than most 87-footers, who require more training than most, and it packs more firepower.
“Instead of 11 “racks,” or beds, and a crew of 10, the Sea Devil will carry 12 racks and a crew of 15 because of the extra hours and training anticipated for the unique mission.
“Along with two .50-caliber automatic weapons mounted on each side of the vessel, a third is mounted near the bridge.”
They have a lot of other boats as well, including some non-standard types, like the one in which the Chairman of the Joint Chief took a ride.
Photo Credit: Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, pilots a 64-foot Special Purpose Craft in Puget Sound, Oct. 04, 2012, as part of a familiarization tour of Coast Guard units in the Pacific Northwest. The special purpose craft is based at the Marine Force Protection Unit in Silverdale, Wash. U.S. Coast Guard photo by Petty Officer 3rd Class Nathan W. Bradshaw.
Thanks to Tim Colton and Lee Walher for help preparing this.
Recently a rather ordinary looking Norwegian coast guard cutter came to the port of Hamburg and created something of a stir. This little craft KV Barentshav (also here), seemed unremarkable, but its power plant was unusual. In addition to diesel, it could be powered by Liquified Natural Gas.
It has been a long time since we saw a shift in fuel for ships, from coal to oil. Now it seems we may be seeing the beginnings of another shift. The big drivers are reduced fuel cost and reduced emissions. The Norwegians seem to be the leaders here, but the US Coast Guard is not totally unfamiliar, particularly the M side of the house. the Dec 2011 issue of Marine Safety Engineering (pdf) had an article predicting that predicted that natural gas fuel vessels were coming soon.
This issue highlights another technology that is becoming more important every day, and that is the increased use of liquefied natural gas (LNG). Whereas, we previously considered LNG as a cargo, new MARPOL regulations for reduced emissions are now making it an attractive fuel source. It is extremely clean burning and is much lower cost than similarly clean diesel fuel. Marine Safety Engineers are leading the charge in establishing the appropriate safety standards needed for LNG fueled vessels, which not only includes the vessels themselves, but also bunkering facilities and waterways risk management.
Based on the current forecasts, natural gas delivered for production of LNG is now at least 70% less expensive on an energy equivalent basis than marine residual fuel and 85% less expensive than marine distillate fuel. EIA currently projects that this relative price advantage will continue, and even increase, through 2035.
LNG does require approximately twice the volume for the same energy content and the infrastructure for its distribution is still limited. Currently engines designed to burn LNG are built by Wartsila, Rolls-Royce, and Mitsubishi. Some of these engines are duel fuel, burning either LNG or conventional diesel fuel.
the US has ample supplies of natural gas,
it may be less than half the cost on a per energy unit basis,
that its use reduces maintenance costs,
LNG is more environmentally friendly, and
the possibility of duel fuel makes this option more practical.
Perhaps the Coast Guard may want to think about powering some of its assets with LNG. When the replacement for the 87 foot WPB is planned, it might be worth a look. They fit the profile of good candidates for LNG since they will normally return to the same base to be refueled. Extending usage to road vehicle and support equipment would amortize the cost of providing the infrastructure and make this option even more attractive.
“The 52 t vessels have an LOA of 90 ft (26.5 m), beam of 20 ft (6.2 m) and draft of 5 ft (1.5 m). Unusual for its size, there is a triple pod propulsion system comprising three Volvo Penta IPS 1050 steerable pod drives with D13-800 diesels each rated at 800 hp at 2,000 rpm (Rating 4 – light commercial application).”
Lower emissions and up to 30% fuel savings are also reported.Top speed is 32 knots and range exceeds 600 nmi.