Bombardment Rockets

As the US Navy developed doctrine for amphibious operations in World War II, one thing it quickly learned was that there simply was never enough suppressive firepower available.  The most famous pre-landing bombardment ships were the  battleships, of course, with their massive 14” and 16” guns pummeling suspected positions for hours, even days before a landing. Of course, cruisers and destroyers hurled tens of thousands of shells upon beaches as well. And we’ve written about the smaller ships such as the LCS(L)(3) series.

When it comes to suppressive fires, quantity has a quality all its own. But naval guns are heavy, expensive pieces of equipment. And so, early on, the Navy turned to the humble rocket as a way to quickly boost its firepower. The first rockets in widespread use was the 4.5” Beach Barrage Rocket, or BBR.

A simple solid rocket motor on the back end of a 20 pound warhead, the BBR was fired from a simple metal rack. It had a very modest range of about 1100 yards, and wasn’t terribly accurate. But it could be carried in large numbers by even the smallest of ships and craft.

The BBR made its combat debut during the Torch landings in North Africa, and saw extensive use throughout the war. The Navy was generally happy with this simple weapon, but also wanted something with longer range, on the order of 5000 yards, or even 10,000 yards.

Rockets launched from the ground, and using fins for stabilization, are inherently somewhat inaccurate. While the wide dispersion of the BBR was tolerable given its maximum range, a rocket for longer range use would have to be more accurate. And so, the Navy tasked CalTech to develop a spin stabilized rocket. After initial efforts looking at a 3.5” rocket, CalTech soon developed a family of 5” rockets that were spin stabilized by slightly canting the exhaust nozzles of the rocket motor. A variety of warheads were available, such as smoke and illumination, but the two most used were “common” shells with high explosive warheads, one with a range of 5000 yards, and one with a smaller charge, but a range of 10,000 yards.

Among the first ships equipped with the 5” High Velocity Spinner Rocket (HVSR) were PT boats.

The Mk 50 launcher could be installed port and starboard aboard a PT just forward of the charthouse. Stored position had them inboard.

But for firing, they were traversed outboard, so the blast would not impact the relatively fragile wooden decks.

The Mk 50 was fixed in train- that is, the only fired straight ahead. It was, however, fitted for elevation. Varying the elevation of the launcher determined the range of the shot.  Aiming was via a reflector gunsight at the helm. Mind you, a bobbing 80 foot boat wasn’t the most stable platform, but the rockets added considerable firepower to boats that already punched above their weight.

The biggest users of the 5” HVSR were the LMSRs, or Landing Ship, Medium, Rocket. The LSM, widely used in the Pacific in the second half of the war, was adapted to carry hundreds of rockets. Early iterations used 5” aircraft rockets on dozens of four rail launchers.

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Later versions used the 5” HVSR. But the penultimate rocket ship was an LMSR with the Mk 102 automatic rocket launcher.

[youtube https://www.youtube.com/watch?v=rUGfu0wWrwI]

The Mk 102 was derived from the powered twin mount Bofors 40mm. A handling room directly below the mount fed rockets to the launcher. The 8 or 10 launchers on an LMSR were directed from a central gun director on the pilothouse.

The Navy was quite pleased with these ships, and kept them in reserve after World War II. They would see further service, even into the Vietnam war.

These ships were, however, wartime expedients, and suffered from some compromises that the Navy sought to overcome. For one thing, their magazines were above the waterline, and thus terribly vulnerable, as the ships were essentially unarmored. Further, the beaching hull meant that their top speed was quite limited. Of course, with a fleet of dozens of newly built LSMRs in reserve, and the war over, there simply wasn’t any money to design a better ship. But the Korean War changed that, making money quite available for a prototype. Laid down in 1952, the ultimate rocket ship wouldn’t be finished in time for that war. But the USS Carronade (IFS-1) would go on to serve in Vietnam for nearly four years. Armed with the slightly improved Mk 105 automatic rocket launcher, she and a handful of recommissioned LSMRs would provide call-fires and pre-planned fire support

[youtube https://www.youtube.com/watch?v=DEIJ4kHuihY]

Of course, no discussion on naval barrage rocketry would be complete without at least a passing mention  of our national anthem. The Star Spangled Banner’s line about “…the rocket’s red glare…” refers to the Congreve rocket, used by the Royal Navy during its bombardment of Ft. McHenry.

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The Mobile Landing Platform

Before we start writing our series on the evolution of landing craft, let’s address one of the greatest challenges of amphibious operations.

Amphibious landings generally give the attacker the initiative to chose the time and place of their landings. As such, gaining an initial foothold is generally successful, provided reasonable attention has been paid to tactical realities.

Maintaining that initiative is the challenge. The key to this is ensuring a sufficient buildup of troops and logistics to overpower any enemy counterattack.

While the Marines have a reasonable force structure for landing the initial waves of an assault, the buildup phase is therefore critical. And the Marines and the Army both have significant numbers of ships dedicated to carrying the vehicles and supplies that any buildup would require. What is often lacking is a means to land those vehicles and supplies ashore in the absence of significant port facilities.

And so the Marines and the Navy have teamed up to build a ship especially intended to connect those prepositioned vehicle carriers with the landing beaches.

The Mobile Landing Platform is designed so that vehicles can be driven off of the prepositioned ship, onto the MLP, and thence onto a Landing Craft Air Cushion for delivery to the beach.

Based loosely on the design of a large semi-submersible heavy lift ship, the MLP can provide docking for up to three LCACs. While designed with fiscal austerity in mind, you’ll notice that the MLP has significant open deck space. Couple that with a reserve of power and water, that means that it can be configured for other purposes rather easily.

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T-MLP-1 USNS Montford Point alongside a Bob Hope Class T-AKR in preparation for vehicle transfer exercises.

It’s important to note that the MLP is not an amphibious warship, nor indeed a warship of any kind. It belongs to the Military Sealift Command, and is crewed by Civilian Mariners. It is an auxiliary to support other ships.

Let’s take a look at an MLP in action.

[youtube https://www.youtube.com/watch?v=mDt7VwKNmYo]

Two MLPs, the USNS Montford Point and the USNS John Glenn, have been delivered.

The basic design of the MLP is also at the heart of the Afloat Forward Staging Base, which will be used as a mothership for mine hunting operations and other forward deployed elements that would otherwise require significant pierside facilities.

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USNS Lewis B. Puller (T-MLP-3/T-AFSB-1)

The Puller and a second, as yet unnamed AFSB are due for delivery in 2015 and 2017 respectively.

The Landing Barge Kitchen

We’re in the middle of drafting some posts on landing craft, past and present. In doing our research, we came across on specialized platform we thought we’d share with you right away.

During Operation Neptune, the sea based part of the invasion of Normandy, there were large numbers of British landing craft that were not assigned to a mothership, nor did they have galley facilities on board. Life assigned to these vessels was tough enough. Craft like the LCM and various LCVP assigned to specialized roles had no berthing, and little or no storage for food, nor even heads for sanitation.

The Royal Navy, realizing this was rather burdensome, looked to provide some level of logistical support to the flotillas of small craft. Building specialized variants of landing craft was not an option. The production of landing craft for the assault wave was already behind schedule. So instead, the RN took up into service numbers of the lighters in use on the Thames River. Some were modified to serve as station tankers for the craft. Others carried fresh water. And then there was the LBK, the Landing Barge, Kitchen.

Given just enough engine power to cross the channel in good weather, it was a floating storeroom and galley.  It could carry enough fresh and bulk foodstuffs to feed 900 men for a week. Up to 1600 hot and 800 cold meals per day could be prepared.

After cooking meals, a day’s rations would be placed in insulated containers, similar to the Mermite can,  and handed across to a landing craft crew. Few thing improve morale and efficiency like a good hot meal.

More on this interesting vessel can be found here.

The Landing Craft Infantry

Faced with the challenge of mounting a cross channel invasion from England to France, the US and Britain realized that small landing craft like the famed Higgins boat would be enough to land the very first assault echelons, but the need to very rapidly build up forces on the far shore would require something more substantial. The ideal craft would lift a reinforced rifle company, be capable of berthing and feeding them for about 48 hours, and be able to land them directly upon the far shore.  The result was the Landing Craft Infantry (Large).

The basic hull was 158 feet long, with a beam of 23 feet. Power was provided by two “Quad Pack” Detroit Diesel engines driving two shafts with reversible pitch propellers.  The Quad Pack was an interesting engine design. No diesel engine of suitable size and power was in production, so Detroit Diesel took four of their existing 6-71 engines, and coupled them to a shared driveshaft. The resulting 1704 cubic inch displacement engine would be used in multiple ships. The LCI(L) had a top speed of about 16 knots, and could maintain 15 knots. At a cruising speed of 8-10 knots, the ship had a range of about 4000 nautical miles, allowing it to self deploy from the US to Britain or to the distance Pacific. While it could self deploy, it could not embark troops for such a voyage.

Nine hundred twenty three LCI(L)s would be built in ten US yards. Two hundred eleven were transferred to the Royal Navy.  Over the course of the program, the design of the deckhouse and the internal arrangements were changed as a result of feedback from the fleet. Originally, two ramps one either side of the bow were used to disembark troops on the beach. First flight ships also had a low, square conning tower. Later ships had a higher, rounded “castle” conning tower with better visibility, and the final batches of ships replaced the ramps with a single ramp through double doors on the bow. These ships also had a larger deckhouse, allowing an increase in troop berthing from 180 to 210.

Original low deckhouse.

Modified deckhouse.

Bow ramp and full deckhouse.

The basic ship was also modified for a variety of roles, such as Flotilla leader, and most famously, gunboats.  The gunboat conversions were so successful that a further 130 ships were built specifically as gunboats, and known as the Landing Craft Support (Large).

Almost immediatley after the war, virtually the entire fleet of LCIs was decommissioned and disposed of. Most were scrapped, though a few were sent to foreign navies or bought by private parties. Today, there are a handful still around, including one in California, and one in Portland, Oregon, undergoing restoration to serve as a museum ship. And one of the volunteers at that example has produced a 42 minute guided tour of LCI-713.

[youtube https://www.youtube.com/watch?v=2m8HyfDa1ZQ]

The ship belongs to the non-profit Amphibious Forces Memorial Museum. The next time I head up there, I’m definitely going to have to visit.

Oh, and as an added bonus, there’s an operational 78’ PT boat in Portland as well. But we’ll save that for another post.

The Army, Amphibious Warfare, and the Engineer Special Brigades- Part II

When we last discussed the Engineer’s role in amphibious warfare, the 1st Engineer Amphibious Brigade had just been gutted to provide longshoremen and stevedore services to the forces involved in Operation Torch, the invasion of North Africa in late 1942.

As we discussed earlier, the Army was eager to come to grips with the main body of the Wehrmacht. As events in North Africa showed, it is just as well that we invaded Africa first. Many lessons were learned fighting the Germans, and most popular histories center on the actions of II Corps under Lloyd Fredenhall at Kasserine. While that first bloody nose was certainly a wake up call to the Army Ground Forces headquarters to revamp and improve unit training, and to the Army staff to improve the equipment of troops, behind the scenes, there were other lessons learned.  And after Patton took over II Corps, the fight became the stuff of legend. The troops might not have covered themselves in martial glory, but Patton certainly did. The real lessons, however, weren’t at the front.

One of the prime lessons “big Army” learned in the North African invasion was the strategic importance of speed and momentum. The initial goal of the invasion was to seize Tunisia, to deny it to the Germans and Italians. But the decision was made to use as much shipping space as possible for troop units, and to deliberately short support, logistical, and supply units. Coupled with often chaotic conditions at the landings, the first forces came ashore, but with little or no momentum. Had the Vichy French forces continued to resist, US and British troops would have been in even more disarray than they were. As it was, a lunge was made to seize Tunis, but the logistics of the entire field army had to be carried over a single, old, poorly maintained rail line. Coupled with a nearly nonexistent road network, the Allies simply couldn’t drive to Tunis fast enough, even with little or no resistance, to occupy the city before the Germans landed enough troops to mount a defense. If the Army had maintained momentum over the beaches, through the assault, and onto the road, they might very well have avoided over five months of bitter campaigning in North Africa.

The Army had allowed the Navy to assume responsibility for landing craft operation during Torch because none of their crews had trained for ship-to-shore movements. The problem was, neither had the Navy crews. The landings in Africa were in shambles almost from the first waves. Virtually all the landing craft used were lost, and there was an awful bottleneck at the shoreline trying to move supplies from the assault shipping over the beach to the forces ashore. If the Navy wasn’t willing to concede a role operating landing craft to the Army, they certainly realized that they’d have to do a better job themselves. Further, there was clearly a need for a specialized organization to operate assault beaches, from the moment the first troops set foot ashore, until the landing beaches were closed and replaced by regular port facilities.  The 1st Engineer Amphibian Brigade would be reconstituted.

Meanwhile, half a world away, GEN MacArthur had problems of his own. With the fall of the Philippines, the bulk of his command was in Australia. Any return to the Philippines would first have to wrest control of New Guinea from Japan. And that meant amphibious operations. Lots of them.  More on that in Part III.

Operation Flintlock – Sixty-seven Years Ago

On this day in 1944, a massive armada began landing US Army, Navy, and Marine Corps personnel on the islands of Kwajalien Atoll, in the central Pacific Ocean.  Allies used the code name “Flintlock” for the operation.  Over the next seven days, the force dislodged, and for all practical purposes annihilated, the Japanese garrison and gained control of the world’s largest coral atoll.  As result, the US drive across the Central Pacific gained another base, extending land-based air coverage out towards the next objective – the Marianas Islands.

Map of Kwajalein

A landing force mostly comprised of the Army’s 7th Infantry Division landed on Kwajalein Island (on the southeast tip of the atoll in the map above) with the objective of an airfield there.  Meanwhile the 4th Marine Division landed on the large island concentration of Roi-Namur in the north to secure Japanese facilities, including another airfield, there.  The somewhat seasoned 7th Infantry had seen prior service in the Aleutians, but was making its first landing in the warmer Central Pacific.  Flintlock was the 4th Marine Division’s first landing (first of four within the next thirteen months!)  Both groups committed just over 20,000 combat troops each.  Defending the Atoll were about 8600 Japanese.

Initial landings on December 31 occupied lightly defended minor islands in the Atoll, to secure landing craft passages for the main landings and to provide firing positions for divisional artillery batteries.  The main landings started on February 1.  After some confusion with landing craft, the Marines secured the beaches at Roi Island and moved inland with deliberate speed.  Remarkably within 27 hours the Marines had secured the major islands in the north, at the cost of 195 killed and 545 wounded.

Clearing a Pillbox on Kwajalein

Observers described the Army’s landings in the south as nearly flawless, among the best conducted in the entire Pacific War.  Terrain constricted movement, and the 7th Division slugged through several pillbox defense complexes over the next few days.  By February 4, save some mopping up, the island was in American hands.  The Army division lost 177 killed and 1037 wounded.  The two forces completed Flintlock with a few additional landings, but by February 8, garrison troops arrived to convert Kwajalein into a major new American base.  Of the entire Japanese garrison (including some Korean laborers), only 265 surrendered.

Aftermath of Battle - Sherman transports a Japanese Tank

The “lessons learned” from Operation Flintlock are many in number.  But three deserve discussion here, as they pertain to military operations (and other endeavors) today as they did then.

First, prior to the operations, the Marines and Army troops practiced… and practiced… and practiced.  The 7th Infantry setup mock Japanese bunker complexes on Oahu, Hawaii based on experience at Tarawa.  These drills paid off during the landings, as the troops moved off the beach, and proceeded to reduce enemy defenses.  Smart, directed training offered a substitute for experience in the Kwajalein landings.

Second, coming behind the long running campaign at Guadalcanal and the nearly disastrous battle of Tarawa, the US Army, Navy, and Marine Corps proved rather adaptable.  Instead of differing doctrine changes to those back in the states, commanders and staff in the combat zone worked out new ways to work around enemy defenses.  Naval ships moved closer inshore to provide gunfire support, and in heavier quantities than before.  Aviation assets learned to provide pinpoint close air support.  The services learned beachhead traffic management.  Logisticians defined “combat loading” procedures.  And the list goes on.  In short, the Americans “learned” in the field and applied those lessons directly to the next action.  This aspect of the “American way of war” continues to this day, with a force which time and time again proves adaptable to the situation.

Lastly, flying in the face of nearly two-hundred years of inter-service rivalry, the Army-Navy-Marine team worked as … well … a team!  At Kwajalein, a Navy Admiral in charge of the operation brought a ground force under command of a Marine general which included a full Army Division (and then some).  Flying long range cover for the entire operation were some fourteen squadrons from the Army Air Forces (gotta work in the USAF somehow here!).  Flintlock was a true joint operation.

Today Operation Flintlock is but a footnote to the larger history of World War II, sandwiched between Tarawa and the “Great Marianas Turkey Shoot” in the books.  Of note, historian S.L.A. Marshall conducted one of his first “oral histories” compiling accounts directly from the soldiers in action.  The resultant work, published as Island Victory: The Battle of Kwajalein Atoll, stands as a landmark for the practice of military history, but also one of only a few studies of the action outside official histories.

I would encourage those interested in this early “joint” operation to read the Army “Green Book” covering the campaign or Volume VII of naval historian S.E. Morrison’s History of United States Naval Operations in World War II.   Marshall’s book, while important, is like many of his works – a labor to read!

-Craig.