Putting Torpedoes on the Webber Class WPC

USCGC Kathleen Moore (WPC-1109)

What is the Problem?:

For a good while, I have been pointing out that the Coast Guard really does not have a means of forcibly stopping a medium to large ship, if its crew is willing to risk death. Even the largest guns the Coast Guard has (76 and 57mm) are unlikely to be able to reliably stop such a ship, and those larger cutters that carry the 76 and 57mm guns are unlikely to be available when needed anyway. They are more likely to be either deployed far from the ports or in maintenance status, unable to respond in a timely manner. There are also no other US military forces positioned and ready to respond to this type threat.

This means, the assets most likely to be available to stop a terrorist attack are Webber class WPCs and smaller vessels. They are armed, at best, with the 25mm M240 chain gun in a Mk38 mount and .50 caliber machine guns. These are even more unlikely to be able to forcibly stop a vessel. In addition there is a good possibility, a hostile vessel used for such a mission could be equipped with weapons that can out gun and out range the cutter. The Mk38 has a reported effective range of 2700 yards. I estimate the maximum effective range of improvised weapons on a terrorist vessel might be as much as 4000 yards. (I have never seen any indication anyone is attempting to train to use anything approaching the 25mm’s maximum range of 7,450 yards.)

Photo: This is a Chinese experiment with improvised armament for civilian ships. Likely useful systems include anti-tank guided missiles, recoilless rifles, heavy machine guns, man portable anti-aircraft missiles, and anti-aircraft and anti-tank guns which are designed to follow fast moving targets allowing them to compensate for movement of the ship. Terrorists would probably make more of an effort to hide the weapons, but you get the idea. 

What is available?:

I believe light weight torpedoes are the lightest, cheapest way to provide the missing capability.

Until recently, I had assumed, we would have to at least reprogram some of our existing light weight torpedoes. Recently I saw a report that the Mk46 mod5 has an anti-surface capability, so it may not be necessary to create or modify a torpedo for the role.

The Mk46 torpedo is not exactly new tech, the original design is over 50 years old and the mod5 version was introduced over 30 years ago. Two newer light weight torpedoes have been developed since introduction of the Mk46, the Mk50 in 1981 and the Mk54 (which uses the propulsion system of the Mk46) in 2004. Because the replacements are more expensive, there are still a large number of Mk46 torpedoes in the inventory. The national fleet (Navy and Coast Guard) has far fewer light weight torpedo armed surface combatants now (85) they did, 30 years ago (229). (At one time, the Coast Guard had quite a few Mk46 torpedoes on the 378s.)

Despite its age, the Mk46 appears adequate to stop most ships. It has an unclassified reported speed 45 knots and a range variously reported as at least 8,000 yards. Its warhead wight is only 98 pounds, about 15% that of the Mk48 heavy weight torpedo’s 650 pound warhead, but the effects of underwater explosions are not proportional to the weight of explosive. The effect, assuming the same explosive is use, is proportional to the cube root of the weight of explosive. This means that the shock experienced as a result of a 98 pounds of explosive underwater is more than half that experienced as a result of the explosion of 650 pounds at the same distance.

We might convince the Navy that putting torpedoes on Coast Guard cutters, is just another place to store them until needed. We are not likely to expend many of them, and if we use one or two, I think they will forgive us.

Why the Webber class WPCs?:

If there is a terrorist attempt using a medium to large ship, a Webber class WPC is likely to be the most capable Coast Guard unit available to attempt to stop the attempt. Larger ships are likely to be either far away or unable to get underway in time.

Perhaps in the future we could also equip the larger cutters and the 87 foot WPB replacement with these weapons, but the WPCs should be the highest priority.

What does an installation look like?: 

American light weight torpedo launchers are all designated Mk32, but they are available in three configurations, triple, stacked twin, and single. The single tube fixed Mod11 is the lightest and probably most appropriate for the WPCs. Two torpedo tubes and two torpedoes are probably sufficient. Support equipment can mostly be left at a support facility ashore.

Surface Vessel Torpedo Tube, Mk32 mod11

These systems are relatively small, 11’4″ in length and less than two feet wide. Loaded with a Mk46 torpedo, each tube weighs 1160 pounds. They do require 9’6″ of open space behind the breech for the tray used to load the 8’6″ long torpedo.

Where to put install?:

In regard to putting torpedoes on Webber Class cutters, one question I have gotten is, “where would you put them?”

I see three likely locations. All three would require some minor modifications to the ship.

  1. On the stern aimed aft to fire over the transom.
  2. On the O-1 deck behind the bridge firing forward and slightly to the sides.
  3. On the O-1 deck forward of the bridge firing forward and slightly to the sides.

The first would require some rearrangement of deck outfit.

The second and third options would likely require about a three foot wide and 12 foot long extension to the O-1 deck on both sides essentially covering the walkway between the main deck superstructure and the side of the hull. This would allow mounting and access to the tubes which would be pointed at a shallow angle outboard placing the muzzle just inside and above the ship’s side. The breech would be angled in so that it is accessible for loading from the clear space behind it.

Personally I prefer the second or third options.

If there is ever a question “Are cutters are large enough to launch a light weight torpedo?” this should dispel any doubts. Below is a photo of a 12 meter (40 foot) Unmanned Surface Vessel with two torpedo tubes. It also has a dipping sonar (presumably the type used by helicopters).

“Too Small to Answer the Call”–USNI Proceedings

The May issue of US Naval Institute Proceedings is the Naval Review issue. It includes updates on the Coast Guard as well as the Navy and Marine corps that are behind the membership pay wall, but it also has an article, “Too Small to Answer the Call,” by Capt. David Ramassini, future CO of USCGC Kimball (WMSL-756) that is accessible to all, and I think is worth a read.

Basically he is advocating using the Coast Guard internationally to build capacity and counter threats of lawlessness and poor governance in trouble spots all around the world. Below is his recommended building program.

Build a New Great White Fleet

Enhancing regional security in partnership with willing nations requires a 21st-century Great White Fleet of forward deployable (or stationed) national security cutters (NSCs), offshore patrol cutters (OPCs), and fast response cutters (FRC). The mix of platforms and duration of presence would be tailored to the distinct geographies and vary based on the receptiveness of the host nation(s), problem sets to be addressed, and mutual goals of the combatant commands and partner nations. Building on a proven bilateral approach for counterdrug operations and EEZ enforcement, the Great White Fleet would leverage existing agreements—based on the extent to which partner governments are willing—to strengthen CTOC (counter transnational organized crime–chuck) and CT (counter terrorism–Chuck) across the JIME (Joint Interagency Multinational Environment–Chuck).

From an acquisition perspective, doubling the size of both the OPC (from 25 to 50) and FRC (from approximately 50 to 100) programs equates to the projected cost of one Gerald R. Ford (CVN-78)-class aircraft carrier (approximately $13 billion). Furthermore, procuring an additional seven NSCs over the nine planned would cost the equivalent of one Zumwalt (DDG-1000)-class guided-missile destroyer (approximately $4.2 billion). The NSC and OPC both offer more than three times the on-station time between provisioning than is afforded by a littoral combat ship (LCS).

Building more OPCs also could rapidly grow the National Fleet by leveraging commercial shipyards outside the mainstream industrial complex. These shipyards may be able to provide better value to the government during an economic downturn in the oil and offshore supply industry. Further leveraging this acquisition would continue to drive down the cost of the OPCs and provide an additional industrial base to build a 400-ship National Fleet of ships with far lower operating and maintenance costs than the LCS.

Redirecting proposed future LCS/frigate dollars (approximately $14 billion) to a Great White Fleet to modernize the U.S. National Fleet mix would provide a greater return on investment and more staying power abroad. For instance, building international security cutters—NSCs with Navy-typed/Navy-owned enhancements such as the SeaRAM antiship cruise missile—could offer combatant commanders a truly useful “frigate,” leveraging mature production lines that now operate at only 70 percent capacity. These estimates are for relative comparison and do not include the associated aviation, infrastructure, basing support agreements, and personnel plus-ups that are needed to provide a more credible and persistent presence across the JIME. But investing in a larger Coast Guard and the supporting infrastructure would return high dividends.

I’m not sure I agree, but it is worth considering. We should, however, keep in mind a sentiment expressed by friend Bill Wells that white paint is not bullet proof. We should not perpetuate the idea that only white painted ships can enforce laws, that is a uniquiely American concept and perpetuating it plays into the hands of the Chinese, who have more coast guard ships than any other country in the world.

Still I think there is merit to this concept. It seems to be working for PATFORSWA (Patrol Forces South West Asia). There has already been talk about a similar deployment to SE Asia. We might consider similar detachments of various sizes for West Africa, the Eastern Pacific, and the Marshall Islands.

The additional ships, 7 NSCs, and “doubling the size of both the OPC (from 25 to 50) and FRC (from approximately 50 to 100)” Is clearly arbitrary. There is very little the NSCs can do that the OPCs will not also be able to do cheaper, so I don’t see a need for more NSCs.

If we take on additional international roles it probably will not be done in one fell swoop. It will probably be done incrementally. Captain Ramassini is clearly looking at this as a near term possibility. Some movement in this direction is clearly possible, but it will take a radical change in the Administration, the Navy, and the Coast Guard for this to happen on the scale he envisions.

Meanwhile, if you look at the “Offshore and Aviation Fleet Mix Study,” the Coast Guard actually needs 9 NSCs, 57 OPCs, and 91 FRCs just to meet all of our statutory obligations. That is not far from his 16 NSCs, 50 OPCs, and 100 FRCs. The study and the “Great White Fleet” would both probide 66 large ships (NSCs and OPCs).

Actually the only way I see this happening is if there is a realization that keeping the USN constantly cycling through distant deployments may not be the best way to maintain readiness. That it wears out very expensive ships and drives people from the service, and that perhaps cutters can perform at least some of the presence missions.

My Unfunded Priority List

An earlier post reported a plea by Representative Duncan Hunter, Chair of the Transportation Subcommittee on Coast Guard and Maritime Transportation, for the Coast Guard to provide an unfunded priority list to include six icebreakers and unmanned Air System.

Thought perhaps I would list my own “unfunded priorities.” These are not in any particular order.


Icebreakers: We have a documented requirement for three heavy and three medium icebreakers, certainly they should be on the list. Additionally they should be designed with the ability to be upgraded to wartime role. Specifically they should have provision for adding defensive systems similar to those on the LPD–a pair of SeaRAM and a pair of gun systems, either Mk46 mounts or Mk38 mod 2/3s. We might want the guns permanently installed on at least on the medium icebreakers for the law enforcement mission. Additionally they should have provision for supporting containerized mission modules like those developed for the LCS and lab/storage space identified that might be converted to magazine space to support armed helicopters.

110225-N-RC734-011 PACIFIC OCEAN (Feb. 25, 2011) Guy Mcallister, from Insitu Group, performs maintenance on the Scan Eagle unmanned aerial vehicle (UAV) aboard the amphibious dock landing ship USS Comstock (LSD 45). Scan Eagle is a runway independent, long-endurance, UAV system designed to provide multiple surveillance, reconnaissance data, and battlefield damage assessment missions. Comstock is part of the Boxer Amphibious Ready Group, which is underway in the U.S. 7th Fleet area of responsibility during a western Pacific deployment. (U.S. Navy photo by Mass Communication Specialist 2nd Class Joseph M. Buliavac/Released)

PACIFIC OCEAN (Feb. 25, 2011) Guy Mcallister, from Insitu Group, performs maintenance on the Scan Eagle unmanned aerial vehicle (UAV) aboard the amphibious dock landing ship USS Comstock (LSD 45). Scan Eagle is a runway independent, long-endurance, UAV system designed to provide multiple surveillance, reconnaissance data, and battlefield damage assessment missions. Comstock is part of the Boxer Amphibious Ready Group, which is underway in the U.S. 7th Fleet area of responsibility during a western Pacific deployment. (U.S. Navy photo by Mass Communication Specialist 2nd Class Joseph M. Buliavac/Released)

Unmanned Air Systems (UAS): We seem to be making progress on deploying UAS for the Bertholf class NSCs which will logically be extended to the Offshore Patrol Cutters. So far we see very little progress on land based UAS. This may be because use of the Navy’s BAMS system is anticipated. At any rate, we will need a land based UAS or access to the information from one to provide Maritime Domain Awareness. We also need to start looking at putting UAS on the Webber class. They should be capable of handling ScanEagle sized UAS.

File:USCGC Bluebell - 2015 Rose Festival Portland, OR.jpg

Photo: The Coast Guard Cutter Bluebell sits moored along the Willamette River waterfront in Portland, Ore., June 4, 2015. The Bluebell, which celebrated its 70th anniversary this year, is one of many ships participating in the 100th year of the Portland Rose Festival. (U.S. Coast Guard photo by Chief Petty Officer David Mosley.)

Recapitalize the Inland Tender Fleet: This is long overdue. The program was supposed to begin in 2009, but so far, no tangible results. It seems to have been hanging fire for way too long.

Expand the Program of Record to the FMA-1 level: The Fleet Mix Study identified additional assets required to meet the Coast Guard’s statutory obligations identifying four asset levels above those planned in the program of record. Lets move at least to first increment.

Alternative Fleet Mix Asset Quantities

————–POR       FMA-1      FMA-2      FMA-3       FMA-4
NSC                8             9                 9                 9                  9
OPC              25           32               43                50               57
FRC              58           63               75                80               91
HC-130         22            32               35                44               44
HC-144A       36            37               38                40               65
H-60              42            80               86                99             106
H-65             102         140             159              188            223
UAS-LB           4            19                21                21              22
UAS-CB        42            15                19               19               19

At the very least, looks like we need to add some medium range search aircraft (C-27J or HC-144).

Increase Endurance of Webber Class Cutters: The Webber class could be more useful if the endurance were extended beyond five days (currently the same as the 87 cutters, which have only one-third the range). We needed to look into changes that would allow an endurance of ten days to two weeks. They already have the fuel for it.



Ship Stopper (Light Weight Homing Torpedo): Develop a system to forcibly stop even the largest merchant ships by disabling their propulsion, that can be mounted on our patrol boats. A torpedo seems the most likely solution. Without such a system, there is a huge hole in our Ports, Waterways, and Coastal Security mission.


Photo: SeaGriffin Launcher

Counter to Small High Speed Craft (Small Guided Weapon): Identify and fit weapons to WPB and larger vessels that are capable of reliably stopping or destroying small fast boats that may be used as fast inshore attack craft and suicide or remote-controlled unmanned explosive motor boats. These weapons must also limit the possibility of collateral damage. Small missiles like SeaGriffin or Hellfire appear likely solutions.

40 mm case telescoped gun (bottom) compared to conventional guns.

40 mm case telescoped gun (bottom) compared to conventional guns.

Improved Gun–Penetration, Range, and Accuracy: The .50 cal. and 25mm guns we have on our WPBs and WPCs have serious limitations in their ability to reach their targets from outside the range of weapons terrorist adversaries might improvise for use against the cutters. They have limited ability to reach the vitals of medium to large merchant vessels, and their accuracy increases the possibility of collateral damage and decreases their probability of success. 30, 35, and 40 mm replacements for the 25 mm in our Mk38 mod2 mounts are readily available.

Laser Designator: Provide each station, WPB, and WPC with a hand-held laser designator to allow them to designate targets for our DOD partners.


Vessel Wartime Upgrades: Develop plans for a range of options to upgrade Coast Guard assets for an extended conflict against a near peer.


How Does the Program of Record Compare to Historic Fleets

 The U.S. Coast Guard cutter USCGC Morgenthau (WHEC-722) heads out to sea from its home port in Alameda, California (USA), passing under the Golden Gate Bridge.

The U.S. Coast Guard cutter USCGC Morgenthau (WHEC-722) heads out to sea from its home port in Alameda, California (USA), passing under the Golden Gate Bridge.

A question from a reader prompted me to look at how the “Program of Record” (POR) compares with Coast Guard patrol fleets of the past.

The program of record is
8 NSCs
25 OPCs
58 FRCs

91 vessels total

1990: Looking back at the “Combat Fleets of the World 1990/1991” the Fleet was:
12 WHEC 378′
32 WMECs (16×210′, 10×270′ (three building), Storis, 3×213′, 3×205′)
34 WPB 110′ (plus 15 building)
3 WSES 110′ surface effects ships
4 WPB 95′
85 vessels total
(There were also five Aerostat Radar Balloon tenders.)
2000: “The Combat Fleets of the World 2000-2001” showed
12 WHEC 378′
32 WMEC (13×270′, 16×210′, Alex Haley, Storis, Acushnet)
49 WPB 110′
93 vessels total.
2013: “The Combat Fleets of the World, 16th Edition,” copyright 2013 listed:
3 NSCs
8 WHEC 378′
28 WMEC (13×270′, 14×210′, Alex Haley)
4 FRCs
41 WPB 110′
84 vessels total
Comparing the Program of Record (plus NSC #9) to the fleet of 2000: You can look at it this way,
  • 9 NSCs and 3 OPCs is more than adequate replacement for the 12 WHEC 378s
  • 49 of the FRCs is more than adequate replacement for 49 WPB 110s (and we have only had 41 anyway since the WPB 123 screw up)
  • That leaves 22 OPCs and 9 FRCs to cover for the 32 WMECs.
I think we would all be pretty happy, if we had the Program of Record fleet in place right now. It really would be a substantial improvement, but while the NSCs and the FRCs are well on the way, the first of the long-delayed OPCs will not be delivered until 2021, and, if everything goes according to plan, the last probably not before 2034, at which time even the newest 270 will be 44 years old. A lot can happen between now and then.
The 2000 fleet was, I believe, the benchmark against which the program of record was measured in the Fleet Mix Study. By 2013 we were already down nine vessels. By my estimate, by the time the last 210 is replaced it will probably be 60 years old. That is expecting a lot. Can we possibly expect that none of these ships will become unserviceable before they are replaced? Building no more than two OPCs a year is really too slow. Once the first ship is built, tested, and approved for full rate production, we should accelerate construction to the maximum. That can’t happen until at least FY2022, probably FY 2023.
By the end of FY2022 we should have already funded 7 ships. The remaining 18 would take nine years, if we buy them at the currently projected schedule. Instead we could fund the entire remaining program from FY2023-2027 by doing a single Multi-Year Procurement of 18 ships. If Eastern alone could not do it, Marinette, which like the designer VARD, is also a Fincantieri company, would probably be more than willing to build an additional couple a year, particularly if the Navy stops building Freedom class LCS/frigates.
We could have the program complete by FY2030, four years early.
Thanks to Peter for initiating this line of thought. 

USCGC Citrus (WMEC-300), USCG photo


USCGC Storis WMEC-38)

USCGC Acushnet

USCGC Acushnet (WMEC-167), USCG photo


Breaking Defense Interviews the Commandant

Coast Guard Commandant Adm. Paul Zukunft (right) meets with then-Southern Command chief Gen. John Kelly, now Trump’s nominee for Secretary of Homeland Security.

Coast Guard Commandant Adm. Paul Zukunft (right) meets with then-Southern Command chief Gen. John Kelly, now Trump’s nominee for Secretary of Homeland Security.

Breaking Defense’s Robbin Laird has an Interview with the Commandant and speculates on the prospects for the Coast Guard under the new administration and DHS selectee General John Kelly.

Trump, Kelly, & The Coast Guard: Exclusive Interview With Adm. Zukunft

Its a good one, and even the comments are worth reading. There is much of the same we have heard before. The Commandant has a clear and consistant message and agenda, but there is more detail about a possible role in the far Western Pacific.

“I have discussed with the CNO (Chief of Naval Operations Adm. John Richardson, the senior officer in the Navy) the concept that we would create a permanent USCG presence in the South China Sea and related areas,” Zukunft said. “This would allow us to expand our working relationship with Vietnam, the Philippines, and Japan. We can spearhead work with allies on freedom of navigation exercises as well.”

This is the first time I have seen the phrase “permanent USCG presence in the South China Sea and related areas.” Does that mean we will have a CG patrol squadron working out of Sinagpore or Okinawa (or Cam Ranh Bay), like the one in Bahrain? Or are we just looking at the Webber class WPCs we already know are going to Guam? (Must be more to it than that.) I do think we should put some OPCs in Guam, if only to patrol the EEZ in the Western Pacific.

Until recently we might have considered the possibility of basing in the Philippines, but that no longer looks like a possibility.

What ever you may think of the incoming administration, for the Coast Guard at least, it looks promising.

Thanks to Luke for bringing this to my attention. 

Webber Class WPC Endurance?

USCGC Kathleen Moore (WPC-1109)

USCGC Kathleen Moore (WPC-1109)

A question, what is the real endurance of the Webber Class WPCs? The figure I see quoted is five days. This was the contract minimum. This is the same as listed for the 87 foot WPBs. Is this correct? This becomes important when the vessel has to make a long transit to and from its patrol area, and if we are understating the endurance, we are selling the class short.

The Webber class vessels are 353 tons full load. Similar sized ships seem to have greater endurance. The Navy’s 387 ton full load Cyclone class PCs have a nominal ten day endurance. The 300 ton Australian Armidale class patrol vessels claim a normal endurance of 21 days and 42 days maximum.

The Webber class’s endurance is not constrained to five days by fuel. The 87 ft WPBs have a nominal endurance of five days but a range of only 900 miles. The Webber class have a range of 2950 nautical miles. Obviously you don’t want to run the ship down to zero fuel, but at ten knots, it would take 295 hours or over 12 days to go 2950 miles. Even at 14 knots, it would take almost nine days to go 2950 miles. Additionally, it is the nature of Coast Guard missions that cutters frequently loiter as low speed which potentially adds patrol time.

A recent news release caught my eye. It reported the results of a 19 day patrol by USCGC Kathleen Moore (WPC-1109). She almost certainly refueled at least once, but did she replenish three times?

We have had these little ships long enough that we should have a revised opinion of their endurance based on experience. Any feedback?


The Mk38 Gun Mount and Ballistics and Weapons Effectiveness Lessons from Pursuit of the Graf Spee, Part 1


Photo: Heavy cruiser HMS Exeter seen after the battle, looking aft from the bow. Both forward twin 8″ gun turrets and the firecontrol system were disabled and the bridge destroyed by “splinters.”  


Note, this has been edited from the original, based on feedback particularly with regard to the ammunition remaining on Graf Spee after the engagement. I don’t believe the thrust of the post has been changed.  

This is the first of two parts. Part one will tell a story. Part two will talk about the implications of lessons learned, applied to how the Coast Guard might deal with the threat of terrorists using a medium to large merchant ship to make an attack.

These are themes that will be discussed in part 2 before looking at specific tactics to make the best use of what we have. Hopefully you will see these illustrated in the following story.

  • In comparing guns, at any given range, the longer ranged weapon generally enjoys an advantage in accuracy.
  • It is very difficult to sink a ship by gunfire alone.
  • Ships’ structure provide a degree of protection that makes it difficult to comprehensively target the crew of a ship without sinking the ship.
  • It is difficult to forcibly stop a ship with gunfire alone.
  • You can run out of ammunition before you accomplish your mission. The depth of your magazine may be important.

But first the story.

To the Germans, it is the story of a lone warrior, that by guile and deception, manages to evade the world’s largest navy for three months. Graf Spee is captained by an honorable and humane gentleman of the old school, Captain Hans Langsdorff, who after seeking a fight with the British and apparently besting them, does the unthinkable, retreating to a neutral port and sinking his own ship, but sparing the lives of his crew.

From the British perspective, it is a story of three little guys, lead by Captain (later Admiral) Henry Harwood, that work together, and despite severe damage, manage to corner a bully. Then by cleaver manipulation, the bully is convinced he has no chance of winning a second round and he self destructs rather than face the Royal Navy again.

Graf Spee Cruise, 1939

Graf Spee Cruise, 1939

The story I will tell is one of how many hits, how many rounds expended, how many rounds remained, and unlikely, almost invisible, but critical damage.

The British had made the Deutschland Class, of which the Graf Spee was the third and last, something of a boogeyman, bestowing on them the description “pocket battleships.” In fact they lacked the protection implicit in the battleship description. The Germans called them simply “Panzerschiff,” (armored ships) and in 1940 reclassified the surviving ships as heavy cruisers. Graf Spee was little better protected than the ships she would fight. She was in fact a large heavy cruiser, but there were others that were larger and better protected, including the German Hipper class (the first commissioned in 1939) and the American Baltimore and later cruiser classes (the first commissioned in 1943). The Japanese and Italians, who were also cheating on their treaty commitments, had several cruiser almost as large.

(Note: the distinction between heavy cruisers and light cruisers was one of gun caliber, not displacement. Light cruisers’ heaviest guns were 6.1″ (155 mm) or smaller. Heavy cruisers carried guns larger than 6.1″; usually 8″ (205mm) guns which were the largest cruiser guns allowed signatories of the Washington Naval Treaty.)

On the other hand, the guns of the Deutschland class were exceptional. These ships were a very real tactical problem for the British, since no single cruiser could deal with them individually. The British considered they needed 70 cruisers to meet their needs and they never approached that number. If they had to double up, there would be many needs left unfilled.

Admiral Graf Spee in the English Channel in April 1939. U.S. Naval Historical Center Photograph # NH 89566.

Admiral Graf Spee in the English Channel in April 1939. U.S. Naval Historical Center Photograph # NH 89566.

The Ships: 

  • Admiral Graf Spee, 16,200 tons (full load), 610 ft (186 meters) loa, six 11″, eight 5.9″, six 4.1″, eight torpedo tubes, 26 knots (reduced to 24 by a fouled bottom), crew 1,134.
  • HMS Exeter, (one of the smallest of the treaty heavy cruisers) 10,490 long tons (full load), 575 ft (175 meters) loa, six 8″ guns, four 4″, six torpedo tubes, 32 knots, crew 630.
  • HMS Ajax and HMNZS Achilles, 9,740 tons (full load), 555 ft (169 meters) loa, eight 6″ guns, four 4″, eight torpedo tubes, 32 knots, crew 570.

Note the total displacement of the three Commonwealth cruisers totaled 29,970 tons, almost twice the displacement of Graf Spee.

HMNZS Achilles,photo, State Library of Victoria - Allan C. Green collection of glass negatives.

HMNZS Achilles. Photo, State Library of Victoria – Allan C. Green collection of glass negatives.

The Guns:


  • British 8″/50 MkVIII (203mm), 256 lbs.(116.1 kg) projectile, 3-4 rounds/minute, range: 30,650 yards (28,030 m). Time of flight to 20,000 yards (18,290 m), 38.4 seconds, elevation for 20,000 yard range: 16.5 degrees
  • British 6″/50 BLMkXXIII (152mm), 112 lbs.(50.8 kg) projectile, 6-8 rounds/minute, range: 24,500 yards (22,400 m). Time of flight to 20,000 yards, 47.2 seconds, elevation 24.1 degreees.
  • British 4″/45 (102 mm), 31 lbs (14 kg), 10-15 rounds/minute, range: 16,300 yards (14,950 m)


  • German 11.1″/52 (283mm), 661.4 lbs (300 kg) projectile, 2.5 rounds/minute, range: 39,890 yards (36,475 m) at 40 degrees elevation. Would have been more if 45 degrees elevation had been possible, elevation for 20,000 yard range: approximately 11 degrees.
  • German 5.9″/55 (149mm), 100 lbs. (45 kg) projectile, 6-8 rounds/minute,  range: 25,153 yards (23,000 m) at 40 degrees elevation, would have been slightly greater if 45 degree elevation had been possible.
  • German 4.1″/65 (105mm), 35 lbs (15.8 kg) projectile, 15 – 18 rounds/minute, range: 19,357 yards (17,700 m).at 45 degree elevation.


Photo: After superstructure of Admiral Graf Spee showing 15 cm/55 and 10.5 cm/65 guns. Note the burned-out Arado Ar 196A-1 floatplane on the catapult and the after main-director rangefinder. Photograph taken at Montevideo, Uruguay in mid-December 1939, following the Battle of the River Plate. U.S. Naval Historical Center Photograph # NH 80976.

How Deep Is Your Magazine?:

The number of rounds carried by each ship would become important as the engagement progressed and as options were weighed. Total weight of rounds available was also an important variable determining how much damage could be inflicted:

Graf Spee: 322.6 tons

  • 11.1″: 720 rounds, 661 lbs each: 475,920 lbs or 238 tons.
  • 5.9″: probably 800 rounds, 100 lbs each, 80,000 lbs or 40 tons
  • 4.1″, probably 2550 rounds, 35 lbs each, 89,250 lbs or 44.6 tons

British: 296.25 tons:

Exeter: (86.05 tons)

  • 8″: 600 rounds, 256 lbs each: 153,600 lbs or 76.8 tons
  • 4″  600 rounds, 31 lbs each, 18,500 lbs or 9.25 tons

Ajax & Achilles (210.2 tons)

  • 6″: 3200 rounds, 112 lbs each: 358,400 lbs or 179.2 tons
  • 4″, 2000 rounds, 31 lbs each, 62,000 lbs or 31 tons
From official British report into the cruise of the Graf Spee and Battle of the River Plate. Published by HMSO (His Majesty's Stationery Office).

From official British report into the cruise of the Graf Spee and Battle of the River Plate. Published by HMSO (His Majesty’s Stationery Office).

Battle Before Breakfast:

It is 13 December 1939. In the Southern Hemisphere, this is one of the longest days of the year. As the sun comes up, Graf Spee sights masts on the horizon. Believing the ships to be a cruiser and two destroyers escorting a convoy she had hoped to attack, she turns toward them and accelerates.

6:10: Graf Spee’s increased speed results in more smoke and she in turn is seen by Commodore Harwood’s cruisers. In accordance with their previously planned response, the cruisers divide up, so that Graf Spee will have two separate groups to engage about 90 degrees apart. Heavy cruiser Exeter goes NW and the two light cruisers go NE. Additionally this should allow the two groups to spot fall of shot and provide range correction for each other.

06:18 Graf Spee opens fire at a little less than 20,000 yards. Exeter at 06:20, Achilles at 06:21 and Ajax at 06:23.

From the first, Graf Spee’s fire, targeting Exeter, is accurate. First salvo over, second salvo short, third salvo straddled. A near miss, bursting short, kills the crew on the starboard torpedo tubes and damages Exeter’s two spotter planes, which are jettisoned. It is textbook gunnery, the rocking ladder. Only one salvo of three is expected to yield any hits. Even then, dispersion of the rounds means, even if the fire control solution is perfect, it is unlikely more than one round out of a salvo would hit. Straddles that include no hits are common. So under ideal condition, if everything worked perfectly, the best one could expect would be that, one round of 18 would hit.

But the adversary is also doing everything he can to throw off the gunnery solution. Assuming the gun line is perpendicular to the base course, at 30 knots, a 30 degree course change for only thirty seconds will change the range 250 yards. At long range, this can be done between the time the guns fire and the shells impact. Both sides used smoke and evasive maneuvers to complicate the fire control problem.

At 06:26, Graf Spee scores a direct hit on the “B” turret (second turret on the bow). Splinters wipe out the entire bridge crew with the exception of the Captain and two others. The Captain is wounded but continues to command the ship. For the rest of the action, the ship is controlled by messenger to after steering.

06:37 Ajax launches her spotter plane to observe and provide correction of the cruisers’ gunnery.

06:38 Exeter is hit twice. One hitting the “A” (most forward) turret and putting it out of action, the other strikes the hull starting a fire.

“At this point, Exeter was severely damaged, having only “Y” turret still in action under ‘local’ control, with Jennings (Gunnery Officer–Chuck) on the roof shouting instructions to those inside. She also had a 7° list, was being flooded and being steered with the use of her small boat’s compass. However, Exeter dealt the decisive blow; one of her 8 in (200 mm) shells had penetrated two decks before exploding in Graf Spee′s funnel area, destroying her raw fuel processing system and leaving her with just 16 hours fuel, insufficient to allow her to return home.

“At this point, nearly one hour after the battle started, Graf Spee was doomed; she could not make fuel system repairs of this complexity under fire. Two-thirds of her anti-aircraft guns (two out of three mounts–Chuck) were knocked out, as well as one of her secondary turrets (one of eight guns–Chuck).

06:40 A near miss on Achilles–splinters kill four, wound several others, and temporarily disable the main fire control director.

07:25 An 11″ shell puts one of Ajax’s after turrets out of action and jams the other. She now has use of only half of her 6″ battery.

07:30 Flooding shorts out power to Exeter’s only remaining turret.

About this time, it appears Graf Spee begins to break off the engagement and heads for the River Plate.

07:40 Now listing heavily, with all major guns disabled and her speed reduced due to flooding in the bow, Exeter breaks off action and begins a long retirement to the Falklands where she will make temporary repairs before returning to Britain for a 13 month refit.

About the same time the Exeter turns to disengage and begin her transit to the Falkland, Commodore Harwood, having closed to close to 8,000 yards, hears reports he is running short of ammunition. He probably also realizes he is in a very dangerous position where his adversary’s shooting is much more accurate. He changes tactics, opens the range and plans to make a night attack when an effective torpedo attack is more likely.

Ajax and Achilles drop back and follow Graf Spee as it becomes obvious she is heading for the mouth of the River Plate. Some shots are exchanged, but these appear to be only Graf Spee warning the cruisers to maintain their distance.

Late in the evening Graf Spee anchors in Montevideo harbor.

The following day she releases her 62 merchant navy prisoners, transfers wounded to hospitals ashore, and buries her dead.

How accurate were they?:

The British light cruisers fired 2064 x 6″ projectiles and scored 17 hits or one hit for every 121 rounds fired or 0.82%. Of their original 3200 rounds 1136, 35.5%, remained.

Exeter fired 193 x 8″ rounds (possibly a few more) and scored three hits or one hit for every 64 rounds fired, 1.55%. This is all the more remarkable because 177 of these are fired by the after twin turret, most of which were fired under local control, and Exeter never closed the range to the degree the light cruisers did. It appears one of Exeter’s three hits was made while the gun was in local control.

Graf Spee fired 414 x 11.1″ rounds. Graf Spee’s 11.1″ hit Exeter at least seven times plus a particularly damaging near miss, along with several others that caused minor damage. These guns also made two hits on Ajax and a damaging near miss on Achilles. If we assume ten hits, that is one hit for every 41 rounds fired or  2.4%. Graf Spee had only 306 rounds, 42.5%, remaining. If she continued shooting with the same degree of accuracy, these could be expected to score at best eight more hits.

My primary source indicates that Graf Spee’s relatively powerful secondary armament fired 377 x 5.9″ and 80 4.1″ projectiles, but made not hits. They should have performed similarly to the British 6″. “It was not known until later that splinter damage to the director directing the 15 cm fire caused bearing track inaccuracy for the 15 cm fire…a small shell splinter entered the starboard director (of assume the forward conning tower FC station). But as luck would have it, the optic was left intact and the director function but little impaired, so the damage remained unknown until late in the evening. The casualty was not noticed by the operator during the battle at all. However, the director did not provide the proper fine bearing angle alignment to the battery, resulting in very poor on target performance.”

A Second Round?:

Diplomatic rankling begins almost as soon as Graf Spee anchors, with the Germans asking for two weeks in port to make the ship seaworthy enough to deal with the North Atlantic winter. The British first try to have Graf Spee’s stay limited to 24 hours, and then, realizing it will be several days before their heavy units arrive, they attempt to keep her in port without saying so.

The Uraguian authorities are unmoved and give the Graf Spee 72 hours.

Meanwhile the Royal Navy has ordered a battlecruiser, an aircraft carrier, and eight cruisers to converge on the River Plate to make sure Graf Spee does not escape.

22:00, 14 December, Heavy cruiser HMS Cumberland arrives, having steamed at full speed for 36 hours from the Falkland Islands. 28% Larger than Exeter (13,450 tons full load and 630 ft loa), with 33% more 8″ guns, she brings with her full magazines, 800 rounds of 8″.

17 December, Graf Spee sets sail, but a large portion of her crew has already left the ship. She stops, anchors, the rest of the crew leave the ship, transferring to waiting tugs. A series of explosions erupt and Graf Spee settles in shallow water, her guns and superstructure still out of the water.

Why did they do it?:

The British provided disinformation that the battlecruiser Renown and aircraft carrier Ark Royal were waiting outside and the Graf Spee crew members convinced themselves they saw the masts of these ships offshore.

Even an accurate view of the odds looked unfavorable for a successful sortie. After the arrival of HMS Cumberland, Graf Spee faced a force at least as powerful as the one engaged on the 13th. Additionally, the three cruisers waiting off shore did not have to sink Graf Spee to be successful. All they really had to do was shadow her until the heavy units could join them and Graf Spee’s fate would be sealed. With less than three quarters the ammunition she had used in the first engagement and her forward fire control director already disabled, Graf Spee’s chances of inflicting significant damage, escaping her tormentors in the South Atlantic, getting through the British blockade of Germany, and making it home appeared slim.

Then there is the matter of the fuel oil purifier. Without it, they could not expect to make it back to Germany, even if the Royal Navy were not in their way.


Annex. Extracts from H. M Ships Damaged or Sunk By Enemy Action, 3 Sept 1939 to 2 Sept. 1945

EXETER during the “Battle of the River Plate”, came under shell fire from the German Pocket Battleship, ADMIRAL GRAF SPEE.

Hit No. l, struck the shelter deck just abaft “B” Turret and passed out through the superstructure side without exploding.

Hit No. 2, struck the front plate of “B’ Turret between the two guns and detonated on impact. “B” Turret was seriously damaged and put out of actions. Splinters caused damage and casualties on the bridge.

Hit No. 3,, struck on or very near, the fluke of the starboard sheet anchor and detonated on impact. The side plating was split and torn and much damage in the paint shop was caused by splinters.

Hit No. 4, struck the forecastle deck on the middle line just aft of the cable holders and exploded on impact. A hole 10 ft. by 10 ft. was blown in the forecastle deck and splinters penetrated the upper deck.

Hit No. 5, struck the jacket of the right gun of “A” Turret, and exploded on impact. “A” Turret was put out of action although it was found later that the turret could be trained and the left gun used. The forecastle deck was torn and the upper deck damaged by splinters.

Hit No. 6, passed through the whee!house, charthouse, out through the armament office and exploded just forward of the starboard 4 inch H.A. (High Angle-Chuck) Gun. Damage from splinters was widespread, ammunition in R.U. (Ready Use-Chuck) lockers was ignited, the lower bridge and 25% of the 4 inch armament was put out of action.

Hit No. 7, passed through the ship’s side just under the upper deck abreast “B” turret, travelled aft through the mess spaces on the lower deck and exploded abreast the E.R.A .’s (Engine Room Artificers-Chuck) mess. Damage from splinters was widespread, the fire main was fractured, communications seriously damaged and the lower deck holed. The 4 inch H.A. magazine and handing room were flooded by water escaping from the fractured fire main. Fire broke out in the mess spaces just aft of “B” turret supports.

Splinter Damage. EXETER suffered a great deal of superficial damage from splinters due to shells that burst short. Splinters on the ship’s side near the waterline caused a good deal of flooding. Most aerials were carried away and searchlights, signal projectors;, rigging etc. were badly damaged. One R.U. Ammunition locker was also ignited by splinters.

Fighting Efficiency = Seriously impaired. “A”, “B” and °Y° Turrets and 25% of the 4 inch H.A. armament was out of action. Slight loss of speed due to flooding and consequent heel and trim of the ship.

AJAX during the “Battle of the River Plate” came under shell fire from the German pocket battleship ADMIRAL GRAF SPEE. The direct hit struck the after superstructure port side passed thro’ “X” barbette and exploded in the Admiral’s cabin, starboard side causing slight structural damage. The shell did not detonate but burst with a mild explosion. Splinter damage caused, “Y” turret to jam.

(Ajax was again hit by a 283 mm (11.1 in) shell that destroyed her mast and caused more casualties, but damage was apparently not worth reporting–Chuck)

Fighting Efficiency = Impaired, “X” and “Y” turret were out of action due to the shell hit. “B” turret had one gun out of action due to failure of the hoist.

ACHILLES during the “Battle of the River Plate” came under shell fire from the German pocket battleship ADMIRAL GRAF SPEE. Splinters from shells bursting short pierced the ship’s side above the waterline, bridge screen etc, and also caused other slight damage. Minor damage was sustained in the director control tower but after casualties had been replaced it was able to continue in action.

Fighting Efficiency – Not impaired. Gun fire was not efficient until casualties in the D. C.T. (Fire Control Director–Chuck) were replaced. W/T (radio-Chuck) was out of action temporarily.

REMARKS The “Battle of the River Plate” revealed the following items.

  1. Increased protection to vital communications required.
  2. Additional portable telephones required,
  3. Improvement to look-out positions necessary,
  4. Need for increased protection for exposed personnel.
  5. Remote control of the smoke apparatus required.
  6. Square ports to be abolished.
  7. Automatic emergency secondary lighting to be introduced.
  8. Modifications required to telephone hand sets to prevent “jumping off”.
  9. Additional portable pumps to be supplied.
  10. Fire mains to be modified to provide for easier isolation and repair.

Print Sources:

  • Bennett, Geoffrey, Battle of the River Plate, Ian Allen, Ltd., 1972
  • Campbell, John, Naval Weapons of World War Two,  Conway Maritime Press Ltd, 1985
  • Chesneau, Roger, Conway’s All the World’s Fighting ships, 1922-1946, Conway Maritime Press Ltd, 1980

On Line Sources: