Attack Transport APA

We recently discussed the value of our big deck, amphibious aviation ships and concluded that they did not offer sufficient value to justify their cost.  One of the alternative suggestions was to transfer the aviation capability to the fleet’s regular aircraft carriers and relocate the amphibious ground combat element to dedicated transport vessels similar to the WWII Attack Transports (APA).  Let’s consider the APA in a bit more detail.

The WWII APA, as typified by the Haskell class, was designed to carry 1500 troops and their combat equipment.  The ships carried around two dozen landing craft of various types.  The Haskell APA was 455 ft long and had a displacement of 6900 t (light) and 14,000 t (loaded).  Contrast this to the current Wasp LHD class at 843 ft long and 40,000 t displacement and carrying 1700 troops.  The Wasp is nearly twice as long and three times the displacement with around the same troop transport capacity.

                 Haskell     Wasp

Length, ft           455      843

Displacement, t   14,000   40,000

Troops              1500     1700

Haskell Class APA

The APA contains several inherent design advantages compared to our current LXX amphibious ships.

• Number of Landing Craft – The APA carried a couple dozen landing craft, the most common of which was the LCVP which carried around 36 troops and had a speed of around 12 kts.  Contrast this with the current AAV which carries around 20 troops and has a speed of around 7 kts.  The LCVP was reusable whereas the AAV is single use but can function as a poor armored personnel carrier on land.  Also contrast the number of landing craft with the 0-3 LCACs that current amphibious ships carry.  A couple of the new America class LHAs don’t even have a well deck and cannot transport and land any equipment that can’t be loaded onto a helo.  The number of landing craft on the APA and their reusability made the APA less vulnerable to the effects of landing craft attrition.  To be fair, the number of landing craft is less an issue of the type of ship and more one of the type of landing craft although the APA’s use of over-the-side landing craft as opposed to the LXX well decks offers certain advantages in terms of numbers.  To be even more fair, if the modern AAVs are considered landing craft then the numbers are more even but there’s no getting around the fact that the AAVs are one use craft as opposed to the LCVPs.

• Defensive Armament – An APA contained purely defensive anti-air armament (some classes had a 5” gun which was used for anti-air but could provide anti-surface in an emergency).  In a modern context this would equate to simple, self-contained, short range anti-air weapons like CIWS and SeaRAM.  No sophisticated sensor suite would be needed since the weapons contain their own radars.  Contrast this with the sensor suite on an LXX which consists of 2D, 3D, surface search, and air traffic control radars which drives up costs.

• Cost – APAs were basically commercial cargo ships.  Their austere fit kept the cost down which allowed large numbers of ships to be built.  In WWII, 388 APAs were built – we’re struggling to maintain a 30-ship amphibious fleet.  The low cost and large numbers greatly mitigated the impact of a sunken ship.  As we’ve discussed, the sensor suite, fairly extensive weapons suite, and aviation capability drastically drives up the cost of modern LXX amphibious ships.

• Commercial Design – APAs were basically commercial cargo ships.  As such it would be possible and quite reasonable to build them for commercial use with conversion in mind and convert them to transports when needed.  Thus, they would serve a useful commercial purpose for the 99% time when we aren’t conducting major amphibious assaults but still be available when needed.

• Ship To Shore – APAs had the ability to land their entire troop and equipment/cargo load using their organic landing craft.  LXXs are somewhat limited.  In an aviation assault mode, the LXX cannot land most of the Marine’s heavier and most useful equipment.  The lead ships of the America class have no well deck and are limited to only aviation landings which means they can’t land any heavier, useful equipment.

  

So, what does all this tell us?

It tells us that the current big deck LXX amphibious ships are an evolutionary mistake.  They began as an attempt to incorporate aviation, in the form of helos, into amphibious assaults but the concept was carried too far and resulted in hugely expensive ships that have very little use outside their narrow task set of amphibious assault.  The ships are also not very efficient at their main task of actually landing the ground element and their equipment.

We need to give serious consideration to eliminating the big deck LXX amphibious ships, dispersing the aviation element to regular carriers, and using modern APAs to transport and land the ground element.  Along with that, we need to design a reusable landing craft whose only function is ship to shore transport, rather than try to be an all-in-one high speed landing craft / armored personnel carrier / fire support / light tank / whatever else, miracle vehicle.  We keep trying to re-travel the failed EFV path instead of emulating the venerable, cheap, Higgins boat.

The LXX ships are yet another attempt by the Navy to make every ship a single-handed war winner.  Today’s amphibious ships are a combination of fixed wing aircraft carrier, helo carrier, troop transport, cargo vessel, assault ship with, now, rumblings of offensive anti-surface and area anti-air capabilities.  The result is ships that are too expensive to afford in sufficient quantity and too expensive to risk conducting the very task they were designed for – assaults!  You can’t conduct an assault from 25-50+ nm offshore.  We need to return to simple, basic, modified cargo ships as APAs.  

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