Merchant Ship Conversions to Wartime Use

It is no secret that the Navy has nowhere near enough amphibious and logistic support ships to prosecute a sustained war with China.  New construction of sufficient numbers and types of ships when war comes will be impossible given the state of US commercial shipbuilding.  An alternative to new construction is to acquire and convert commercial ships as was done routinely during WWII, especially at the start of the war.

 

Consider the case of troop transports.  At the start of WWII, we had nowhere near enough Attack Transports which were the backbone of the entire Pacific campaign.  Instead, we converted commercial ships to troop transports until we were able to ramp up our wartime shipbuilding.  Here’s a few examples:

 

McCawley Class - The McCawley class consisted of two converted commercial ships built for the American shipping company, Grace Lines, by Furness Shipbuilding Company.  The ships were completed in 1928 as Santa Barbara and Santa Maria. They were bought by the Navy in 1940 and converted to troop transports as the USS McCawley (AP-10) and USS Barnett (AP-11).

 

USS Harry Lee (AP-17) - The Harry Lee was built as the passenger ship SS Exochorda by New York Shipbuilding Co. in 1931 before being acquired by the Navy in Oct-1940 and converted to the Harry Lee (AP-17) in Dec-1940.

 

USS John Penn (AP-51/APA-23) - The John Penn was built as Excambion in 1931 by the New York Shipbuilding Company as one of American Export Lines's original "Four Aces."  She was acquired by the Navy 8-Jan-1942 and converted to a troop transport in Apr-1942.

 

 

Even prior to WWI, the US recognized the need for vastly increased numbers of commercial ships that could be converted to wartime use.  With the 1916 Shipping Act, Congress established an organization to do just that – the United States Shipping Board which, in turn, founded a business, the Emergency Fleet Corporation whose mission was to acquire merchant ships for war needs.

 

Paraphrased from various Wikipedia entries,

 

The Shipping Board had been established while the United States was at peace, with the intent to restore the nation's Merchant Marine.

 

Ten days after declaration of war, on 16 April 1917, the Board created the Emergency Fleet Corporation (EFC) in the District of Columbia with a capital stock of $50,000,000.  The EFC’s purpose was to acquire, maintain, and operate merchant ships to meet national defense, foreign and domestic commerce during World War I.

 

When the United States declared war against Germany the purpose and policy of the Shipping Board and the Fleet Corporation changed from a body established to restore the American Merchant Marine to a military organization tasked with providing transport of war materials to Europe. 

 

The EFC was renamed the U.S. Shipping Board Merchant Fleet Corporation in February 1927, then abolished entirely in October 1936. Its functions were transferred to the United States Maritime Commission.

 

The EFC operated together with some 80 shipyards throughout the country to design commercial ships suitable for conversion to war use.  For example, the Design 1029 ship (full name Emergency Fleet Corporation Design 1029) was a steel-hulled passenger/cargo ship designed to be converted in times of war to a troopship.

 

Today, China does something along these lines with their commercial ships being designed for rapid conversion to wartime vessels.

 

We see, then, that acquisition and conversion of merchant ships to wartime use has been a common practice throughout history.

 

Given our appalling shortage of transport and logistic ships, we will definitely need to acquire and convert merchant ships.  Unfortunately, the US flagged merchant fleet is lacking in numbers.  The U.S. Department of Transportation, Maritime Administration, lists only 180 US flagged, privately owned, oceangoing ships of 1,000 tons or greater, as of 2021.[1]  The breakdown by type is shown in the table below.

 

 

Ship Type	Qty.
Containership	63
Dry Bulk	4
General Cargo	20
Ro-Ro	26
Vehicles Carrier	3
Tanker	64
Total	180

 

 

Of the 180 vessels, 157 were deemed militarily useful.[1]

 

We don’t need to attempt to build more amphibious or logistics ships but we do need to ‘change the landscape’, so to speak, with the following actions:

 

• Need to require merchant ships to include military conversion features in their design.
• Need to increase the number of US flagged merchant ships by modifying the applicable laws.
• Need to plan for acquisition and conversion of merchant ships.
• Need to have conversion plans for each individual ship in hand and ready to go.
• Need to assess shipyard capacity to accomplish conversions.

 

Most of all, we need some kind of organization tasked with the described acquisition and conversion.  It is unclear to me whether such an organization exists within the government/military.  The ‘s responsibilities have, over the decades, been diluted and distributed among various organizations such as the United States Maritime Administration (MARAD) but none seem to have the charter to produce/ensure that commercial ships are designed for easy and rapid conversion to wartime configurations.

 

Of course, converted merchant ships won’t be perfect fits for wartime uses since they are, after all, merchant ships at heart.  For example, we can easily convert a merchant ship to a troop transport, like we did in WWII, but we can’t convert it to a big deck, aviation ship of the type the Navy currently procures.  However, this fits well with the blog’s overall ship design philosophy of single function, cheaper, smaller ships.  The Navy needs to institutionally come to grips with this reality – and desirability!  We then need to revise our doctrine and operations to include these types of ships instead of the big deck, aviation ships we have today.

 

One final consideration is the cost of naval amphibious or logistic ships – they’re expensive to buy and operate!  By having a fleet of merchant ships capable of being usefully converted to wartime work, the Navy largely avoids the cost of procuring and operating the ships while still having access to the numbers and capabilities the ships represent.  Thus, the cost of administering such a program would easily pay for itself.

 

 

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Related Note:  Following is an example of a commercial ship, the SS United States, designed for conversion to wartime needs.  The ship was designed and acquired under the direction of the United States Maritime Commission (MARCOM) which succeeded the United States Shipping Board.  From Wikipedia entries,

 

… the US government sponsored the construction of a large and fast merchant vessel that would be capable of transporting large numbers of soldiers. Designed by American naval architect and marine engineer William Francis Gibbs (1886–1967), the liner's construction was a joint effort by the United States Navy and United States Lines. The US government underwrote $50 million of the $78 million construction cost, with the ship's prospective operators, United States Lines, contributing the remaining $28 million. In exchange, the ship was designed to be easily converted in times of war to a troopship. The ship has a capacity of 15,000 troops, and could also be converted to a hospital ship.

 

The vessel was constructed from 1950 to 1952 at the Newport News Shipbuilding and Drydock Company in Newport News, Virginia. The hull was constructed in a dry dock. United States was built to exacting Navy specifications, which required that the ship be heavily compartmentalized, and have separate engine rooms to optimize wartime survival.[2]

 

SS United States

 

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[1]https://www.maritime.dot.gov/sites/marad.dot.gov/files/2021-04/DS_USFlag-Fleet_2021_0316_Bundle.pdf

 

[2]https://en.wikipedia.org/wiki/SS_United_States

Eliminate Aviation Amphibious Ships

The Navy’s dilemma in amphibious assaults is that they don’t want to risk the high cost, high value ships like LHA/LHDs close to shore.  Well of course they don’t !  Those ships cost several billion dollars each and we have way too few to risk.  Unfortunately, that means we can’t actually execute an amphibious landing because the ships have to stay too far from shore for the landing craft to get there with the troops in any kind of functional condition.

What’s the problem?  Why has this situation occurred?  Can we do anything about it?

Let’s start by asking, why do we even have a problem?  It’s because we did something very foolish some time ago: we combined an aircraft carrier and a troop transport to get the LHA/LHD.  The LHA/LHDs are gigantic ships that cost a fortune and cram both the aviation element and the ground element together in the same ship.  Talk about concentrating risk!  If we lose a LHA/LHD, we lose both elements and several billion dollars worth of investment.

Wasp Class LHD - Ground + Aviation

Yeah, that’s true, you say, but that’s the way it’s always been.  Wrong, bilge breath!  In WWII those functions were separate.  Let’s recall how it was done then.

The aviation element, in WWII, was contained on a small escort carrier.  This carrier was free to maneuver and remain well off from the landing site because a few dozen, or more, miles meant nothing to the airplanes.  Thus, the carrier could provide effective support for the ground troops without having to risk the ship, itself.

The troop transports (APA attack transports) were free to move in near shore to unload their troops into landing craft.  Being smaller, with the risk widely dispersed, the transports were expendable in the sense that the loss of one would not cripple the entire assault.

We need to return to this model.  We need to separate the aviation and troop transport functions.

We need to build small carriers that house the assault aircraft and that have no other function.  These small carriers can stand as far off from the landing site as needed.

We also need to reevaluate what constitutes assault aircraft.  If the assault aircraft are dedicated to ground support (as opposed to air-to-air fleet defense) then they don’t necessarily need to be high performance stealth fighter designs.  They could, potentially be more akin to an A-10 or Skyraider.

We need to build small (on a relative basis) WWII type troop transports, each with a couple dozen landing craft (which also need to be designed and built).  This reduces the cost, disperses the risk, and makes a landing actually feasible again.

Attack Transport

Eliminating big deck amphibious ships and breaking them up into small, separate, ground support carriers and troop transports reduces risk, reduces cost, and increases the feasibility of amphibious assaults.  Let’s do it, Navy! 

Separate Aviation From Amphibious

During WWII, amphibious troop delivery to the beach was provided by small, specialized transport ships, the attack transports (AP/APA).  The APA carried two dozen reusable landing craft that were stored above deck and launched over the side.  Thus, the full internal volume of the ship was available for troop and supply storage instead of needing a voluminous well deck.

The other distinguishing feature of the APA compared to today’s amphibious ship was the absence of any aviation capability.  True, the helo had not yet been developed but it would have been possible to build a combination carrier-troop transport, just as we have today, and yet the ship designers opted not to do that for a variety of reasons.

I don’t claim to know the thinking of ship designers of that time but here are a few considerations that I would assume impacted their thought process and which should impact ours, today:

Volume of Firepower Delivery – Aviation simply can’t provide the volume of explosives delivery required to support an assault.  An aircraft, then or now, is limited to a small handful of bombs/missiles and can generate, at most, a few sorties per day before maintenance needs ground the aircraft.  Pilot rest is also a factor.  So, three sorties per day per aircraft is simply, woefully inadequate when the requirement is for continuous bombardment for days on end.

That being the case, that aviation can’t even begin to provide the requisite firepower delivery, why design a ship dedicated to that purpose?  Firepower delivery was left to the heavy gunned naval ships and aircraft chipped in when and where they could.

Yes, aircraft can supply small scale, close air support to ground forces (weather and aircraft availability permitting, of course, and assuming no enemy air forces in the vicinity) for use against a few, specific targets but that hardly justifies the expense of a dedicated aviation-centric amphibious-troop ship.

Fleet Defense – No fleet, no assault.  The fleet’s existence comes first.  Thus, ALL available aircraft will be used for establishing air superiority, first and foremost.  The aircraft of WWII and those of today had, and will have, as their primary responsibility, fleet defense.  Today’s LHA/LHDs, with their F-35Bs, will be tied up fighting for air space and defending the fleet in any peer defended assault scenario.  Those F-35Bs will not be available for ground support – not that a handful of F-35Bs constitute an significant firepower delivery, anyway.  Later, days or weeks into the assault, when air superiority has been established, the F-35s will become available for ground support but, of course, by that time it won’t matter.  The assault will have already succeeded or failed.

Risk Dispersal – Today’s LHA/LHD encompasses 1500 troops, their supplies, ship to shore connectors, F-35Bs, combat helos, transport helos, medical facilities, etc.  That’s a LOT to risk in a single ship.  WWII ship designers were all about dispersal of risk.  This alone dictates to any reasonable force designer that the aviation and troop transport functions should not co-exist in a single ship.  The risk is too geat.  Lose an LHA/LHD and you lose a third+ of a MEU plus most of the MEU’s aviation assets.  That’s a foolish risk to take.

Cost – A WWII APA was just a short term (term of the war) troop transport.  Indeed, many were converted from commercial liners.  The purpose built APAs were bare bones, no frills, troop transports.  Troop comfort was not a consideration, nor was ship longevity.  These APAs were not the glorified luxury cruise ships of today.  APAs were quick, easy, and cheap to build.  Adding an aviation capability would only drive up cost and reduce the number of vessels that could be built.  Then, as now, the addition of aviation would either cut the troop and cargo capacity in half or double the size of the ship. 

Troop Delivery Efficiency – As noted, APAs stored their landing craft (ship to shore connectors, as we now refer to them;  aside: when you start giving basic functions fancy names, you know you’ve lost sight of what’s important) above deck, launched them over the sides, and disembarked the troops over the side.  This method allowed for the carry of large numbers of landing craft without impacting troop capacity by taking up precious internal volume with well decks.  The addition of a flight deck to an APA would have forced the landing craft to be stored internally or, in reduced numbers, in boat pockets on the ship’s sides.  The LHA/LHD of today demonstrate this with their landing craft (those that even have them!) carried in large well decks.  Proponents might argue that the well deck allows easier, more efficient loading of the landing craft.  This may or may not be true.  An APA could load two dozen landing craft with troops in a remarkably short time and all of them nearly simultaneously.  Today’s amphibious ships can certainly load their landing craft easier but is degree of ease really the issue in combat?  The real question, though, becomes whether the benefits of a well deck (if there are any) outweight the immense loss of internal volume, larger resulting ship size, increased cost of ship construction, and lengthened construction times?

Flexibility – Troop and cargo transport requires that the ship be in a specific location for the duration of the assault unloading.  In contrast, aviation works best when the carrier is free to roam and able to take the best position for whatever task is at hand.  Thus, the two functions are almost diametrically opposed as far as what each needs the host ship to do.  A carrier/transport that is tied to a specific location can’t reposition to meet an enemy assault without abandoning its troop and cargo landing responsibility.  Shades of Guadalcanal ! 

With the above considerations in mind and the lessons of WWII firmly in hand, we have to ask, does it make sense to combine aviation and troop transport in one ship?  The answer seems clear – aviation and troop/cargo transport should be separated.  

Return To Troop Transports

We need to return to smaller, cheaper, easier to build APA type troop transports.  I would go so far as to say we should abandon the LCAC and return to a modern version of the venerable Higgins boat landing craft – but that’s a topic for another post.  These modern APAs should not be cruise ships.  They should not be sent on peacetime deployments.  They should be war vessels - manned and operated when needed but otherwise left pierside in idle status.  If we design such a ship and keep it cheap and quick/easy to build, we don’t even need to keep many in service.  We can simply build them when war comes and just keep enough in service to maintain an institutional knowledge of how to operate them.

The separated aviation component should be simply our standard carriers.  As we noted, the first responsibility of any aviation component is fleet defense so it makes the most sense to leave the aircraft with the aircraft carrier.  When air superiority has been established, the carrier air wing can turn its attention to ground support.  That would provide far more ground support aircraft than the half dozen F-35Bs that a LHA/LHD carries and, after all, isn’t that why the Marines have been so insistent on having their own aviation assets – to ensure and maximize the number of aircraft supporting the ground force?

Optionally, given the shrunken size of our air wings, a additional one or two squadrons of strike aircraft could be added to the regular carrier air wing, specifically to conduct ground support (you know, when not needed for fleet defense!).

USS Nimitz - 1997

Put Amphibious Aviation Back Onto Carriers In The Form Of Extra Squadrons

Get Back To 90+ Aircraft

The only sticking point is the Marine’s desire for attack and transport helos.  For this, it might make sense to have a very small, dedicated helo carrier.  Such a ‘carrier’ would not be a conventional carrier in any sense of the word.  Instead, it would be, essentially, a converted commercial cargo ship with a flat deck  As with the troop transports, it would be a no-frills, non-deployed vessel that is kept pierside other than for training.  Again, just a few are needed to maintain institutional knowledge.

An alternative might be to design a smaller, full-fledged carrier intended to carry a ground support air wing which would include attack aircraft and helos.  The problem with this approach is it provides a much less capable and flexible air wing at nearly the same cost as a regular carrier.

The current path of $4B combined aviation and troop ships is unaffordable and inefficient.  We also need to abandon the peacetime cruise ship mentality, cease deployments, and return to building utilitarian WARships.

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.