Japanese APDs and Marine LAWs

Note:  Credit for this post goes directly to reader ‘Christo’ who brought this up in a comment on the “High Speed Transport” post.

 

As we consider the Marine Commandant’s concept of Light Amphibious Warfare (LAW) ships flitting about the Chinese first island chain, we can look to yet another historical example of the concept (see, “High Speed Transport” for a discussion of the US APD).  In WWII, the Japanese several times attempted to resupply their forward bases using destroyers as APDs.  Some of the APDs were purpose built, the T1 class (1), and others were simply ad hoc destroyers pressed into transport duty.

 

Japanese T1 High Speed Transport

The point is that they used small, fast vessels to attempt clandestine resupply just as the Marine’s believe they’ll use LAWs to attempt resupply of forward bases.  The difference, however, is that the Japanese APDs were fast and well armed.  In contrast the Marine’s LAW is small, slow, non-stealthy, and defenseless.

 

So, how did the Japanese APDs perform?

 

Guadancanal – The Japanese first attempted to conduct resupply using conventional troop transports but suffered significant losses as the transports were easily spotted and attacked.  As a result, they switched to using fast destroyers as troop and cargo transports in an effort dubbed the ‘Tokyo Express’.  Troop laden destroyers would conduct night voyages down the Slot to deliver troops.  Lacking any cargo handling equipment, the destroyers would often dump barrels of supplies into the ocean where troops on the island would attempt to retrieve them with only marginal success. 

 

The resupply effort was an overall failure and many valuable destroyers were lost in the attempt.  Even the successes were pyrrhic in nature since the quantity of troops and cargo delivered did not come anywhere near justifying the ship losses.

 

 

US APD vs. Japanese APD

 

In general, the US APDs enjoyed some success while the Japanese did not even though the ships were functionally identical.  Why the difference in outcome?

 

The US APDs were used for special operations such as raids and were not generally used on a predictable basis or schedule and operated in widespread areas on an almost random basis.  In contrast, the Japanese APDs were used in a very predictable manner and in a very localized area where even the ‘eyeball’ sensors of the time were sufficient to detect them.  Once detected, individual ships were routinely damaged and destroyed.

 

 

Conclusion

 

Despite the lack of modern sensors and night movement, the Japanese ships were generally spotted and attacked.  If fast ships, moving at night, against an enemy with no significant sensors other than eyes could be routinely spotted, how do the Marines believe that the slow, non-stealthy, defenseless LAWs will be able to routinely come and go among the first island chain without being spotted by modern Chinese radar, sonar arrays, EO, IR, air patrols, etc.?

 

It is important to note the key difference between the US and Japanese APDs and that is their Concept of Operations (CONOPS).  As we continually harp on – and the US Navy continually ignores! – a viable CONOPS is the key to ship design and operational success.  The Japanese CONOPS had the APDs operating in a fairly confined area on a predictable basis with an absolutely known destination – a recipe for detection and destruction.  The US CONOPS used the APDs as almost random raiders in unpredictable locations and at unpredictable times.

 

Now, let’s consider the Marines intended use of the LAWs.  They’re intended to operate in predictable locations (with no due respect to the Marine’s wild claims of thousands of islands to operate from, there are only a relatively few worthwhile and feasible locations for the kinds of bases they want to establish), on regular resupply schedules.  Does that sound an awful lot like the Japanese CONOPS?  Yes, it does.  So, why do the Marines expect a totally different outcome?  Same CONOPS … different outcome?  That sounds suspiciously close to the definition of insanity (same set of actions and expecting a different outcome)!  On top of that, the WWII APDs were heavily armed, for their size, and quite fast.  In contrast, the Marine’s LAWs are unarmed and slow. 

 

History is telling us everything we need to know about small, isolated transports but the Marine’s aren’t listening.

 

 

 

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(1)http://www.combinedfleet.com/Dai1Yusokan.htm

High Speed Transport

Here’s a topic that was inspired by reader “Jjabatie” in the “Buckley Vs. Constellation” post.

 

As we know, the Marines have come up with … how can I put this somewhat politely? … an ill-conceived concept to insert small units onto far forward bases and shoot missiles at passing ships while also hunting subs.  The key to this scheme is a new class of … how can I put this somewhat politely? … ill-conceived Light Amphibious Warfare (LAW) ships that are small, slow, not particularly stealthy, and have no defenses.  The idea is that these LAWs would transport troops and supplies to, and between, various islands while making round trips for resupply … all while China remains oblivious (from laughter, one presumes).

 

Okay, this concept is idiotic but there is a historical antecedent at least for the type of small transport that the Marines describe and one whose characteristics would much better serve the concept.  I’m talking about the WWII high speed transport.

 

In WWII, with a need to move smaller units of troops between islands, some destroyer escorts were converted to high speed transports (APD). 

 

From Wikipedia,

 

APDs performed arduous service. They transported troops to beachheads, served as escorts for transports and supply vessels, conducted anti-submarine patrols and survey duties, operated with Underwater Demolition Teams and commando units, performed messenger and transport duties, conveyed passengers and mail to and from forward units, and were involved in minesweeping operations.

 

Typical of these ADPs were the 90+ Buckley and Rudderow class conversions. 

 

USS Bowers (DE-637 / APD-40);  Buckley class APD conversion;

note 5" gun forward and landing craft in davits

 

As an example, in the Buckley conversions, the superstructure was enlarged to house some 160 troops.  This provided a useful degree of both troop and cargo transport capacity while also retaining a useful defensive and ground support capability.  The Buckley’s weapons fit was changed to: (1)

 

• 1x 5-inch/38 dual purpose gun
• 3x twin 40mm gun
• 6x single 20mm gun
• 2x depth charge tracks
• 3x torpedo tubes
• 8x K-gun depth charge launchers

 

Thanks to their 5” gun (upgraded from a 3” gun!), the APDs could provide a degree of fire support for their embarked troops.

 

Of course, the ships retained their inherent speed and maneuverability.

 

Notably, the APDs typically carried four LCVPs (Landing Craft Vehicle and Personnel) in davits.

 

The destroyer history website lists the following specs: (1)

 

Troop capacity: Officers:  12; Enlisted: 150.

Troop accoutrements:  4x LCVP landing craft; 6x 1/4 ton trucks; 2x 1 ton trucks; 4x ammunition carts; 4x pack howitzers.

Ammunition:  6,000 cubic feet.

General cargo:  3,500 cubic feet.

Gasoline:  1,000 cubic feet.

 

 

Compare the WWII APDs with the Marine’s LAW (see, “Berger’s Amphibious Warships”, “Light Amphibious Warship Update 1”, and “Light Amphibious Warship Update 2”) and we see that the APD specs put the LAW to shame in every conceivable way.  If the Marines insist on pushing ahead with their idiotic scheme, an APD type vessel would make far more sense.

 

 

 

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(1)https://destroyerhistory.org/de/apd/