WWII saw the development of the attack transport (APA) with landing craft being carried, launched, and loaded over the side of the ship. More recently, post-war development has seen the development of the well deck, a flooded space in the stern of the ship from which landing craft (the term being used generically to include any type of landing craft or connector) could load and launch.
The well deck was, perhaps, mechanically simpler than the APA approach and allowed for easier loading but suffers from a significantly reduced number of landing craft. The reduced number was supposedly compensated for by the individual landing craft being some combination of bigger and faster. Setting aside the actual capacity and throughput, the weakness in this approach is that there is no allowance for attrition of the landing craft (see, "Amphibious Assault Attrition"). When a ship carries only two or three LCACs, for example, the loss of even one has a near catastrophic impact on the follow-on landings and, more importantly, sustainment phase.
So, given the above weakness, you’d guess that the trend is towards larger well decks that can carry and operate more landing craft, right? Oddly, you’d be wrong. Well decks are becoming fewer and smaller.
Here are the well deck dimensions for recent classes of amphibious ships.
From oldest to newest,
Wasp LHD-1 267’ x 50’
America LHA-6 none
Again, from oldest to newest,
San Antonio LPD-17 170’ x 50’
What jumps out from a cursory examination is that the recent amphibious ships have fewer and smaller well decks. Indeed, the first two members of the
class LHA have no well deck. The LPD-17 has a significantly smaller well deck than its predecessors. What’s particularly disturbing about the LPD-17 is that it is likely to be the basis for the next generation amphibious ship, the LX(R) which is intended as a replacement for the America Whidbey Island and Harpers Ferry classes. If that happens, that will be a LOT of lost well deck space.
There is only one way to get large quantities of supplies, tanks, and heavy equipment ashore and that is via ship/landing craft. As the well decks disappear and get smaller, there are fewer and fewer LCACs available to the ARG/MEU. How do the Marines/Navy think those supplies and heavy equipment will get ashore? I’m baffled by their thinking.
There is, of course, one reasonable explanation that fits the facts. The Marines are abandoning the amphibious assault mission in favor of vertical assault. Consider recent evidence:
- The new LHA was built with no well deck.
- The LPD-17 has a significantly smaller well deck than its predecessors.
- AGR/MEU LCAC numbers are shrinking.
- The Marines are shedding tanks, artillery, and heavy equipment.
- The Marines have committed fully to the MV-22.
- The Marines have indefinitely deferred an AAV replacement.
The simplest explanation that fits the facts is invariably the correct one.
The simplest explanation is that the Marines are getting out of the amphibious assault business and becoming an expeditionary air force and aviation assault force.
What do we hear from the Marines? Are they talking about becoming more powerful? Are they talking about beefing up to be able to knock down the Chinese door? No. They are talking about becoming lighter and more mobile. They are talking about being a crisis response force and humanitarian relief organization.
Back to the well deck, itself. Is it needed? If we’re going to do amphibious assaults then it, or something functionally equivalent, is needed. It’s just not possible to conduct and sustain an assault using purely or mainly aviation assets. We need the ability to transport heavy loads to the landing site and landing craft (in the generic sense) are the only viable option. Now, we don’t necessarily have to use well decks. We can use the old WWII APA and landing craft approach, modern LSTs, or something similar. The point is, we need some means to place heavy loads on landing craft and a well deck is certainly a convenient means to do so.
This discussion goes back to the need for a broad military strategy. Do we, as a nation and a military, see the need to be able to conduct large amphibious assaults? If so, we’re trending in the wrong direction when it comes to amphibious ship design. If we don’t see a need, then we need to re-examine our entire amphibious force structure.
Well decks are a symptom and a bottleneck when it comes to amphibious assaults and the Navy/Marines need to come to grips with the broader issue and choose a logical path based on an overall strategy. Failure to do so will see amphibious assault slowly wither away as it falls prey to the short term budgetary consequences of the latest “shiny toy” acquisitions approach currently in vogue.
An AAV replacement gets indefinitely deferred ...
LSTs are retired with no replacement …
Well decks shrink or vanish ...
Tanks and heavy equipment are cut …
Doctrine moves assault ships further and further offshore ...
Before you know it, no more amphibious assault capability.
Well decks are the canary in the amphibious coal mine and right now the well deck canaries are dying. Well decks are telling us what’s happening but is this what we want to happen?