Merchant Ship conversion to Aircraft Carrier?

By the time you’ve gone to the time and expense of chopping up an MV, you might as well build from scratch leaving off any nice to have but not vital pieces in a similar way to the RN WW2 Colossus class carriers.

With the double hulled tankers the strength is now better divided. Cutting a hole in the deck would be possible. Adding tween decks will also give addition strength to compensate for these possible holes. Steel only costs about 7 dollars a ton, so no real problem there. They would be mounted over large areas, so cost and time of welding will be more or less limited too.

Deck strength is the major problem I think. Most tankers only have a helicopter spot to winch someone up, not to accomodate a helicopter. The last ones, like the Hellespont ULCC’s, have a spot strengthened to let even a Sea King land, safer for pilots to come onboard. Yet that’s again only a single strengthened spot. The remainder of the deck is weaker.
However strengthenin that deck will make it stronger to divide the forces again.
I think it’s possible, but indeed will come at some cost. A tanker is slow though, these Hellesponts are capable of doing 19kts in ballast (at 150,000t displacement) with good weather.

Well, have it converted by a ship yard with cheap labour………….

With the double hulled tankers the strength is now better divided. Cutting a hole in the deck would be possible. Adding tween decks will also give addition strength to compensate for these possible holes. Steel only costs about 7 dollars a ton, so no real problem there. They would be mounted over large areas, so cost and time of welding will be more or less limited too.

Deck strength is the major problem I think. Most tankers only have a helicopter spot to winch someone up, not to accomodate a helicopter. The last ones, like the Hellespont ULCC’s, have a spot strengthened to let even a Sea King land, safer for pilots to come onboard. Yet that’s again only a single strengthened spot. The remainder of the deck is weaker.
However strengthenin that deck will make it stronger to divide the forces again.
I think it’s possible, but indeed will come at some cost. A tanker is slow though, these Hellesponts are capable of doing 19kts in ballast (at 150,000t displacement) with good weather.

Problem with a tanker would be hull rigidity and deck strengh, and because the hull and decks are load bearing you can’t just cut holes like you can with a container carrier. Many older tankers were single hull with added implications fro damage control, although because of the regs on double hulled tankers you could probably pick up an old tanker for nothing. Other thing is speed, tankers tend to be slow, probably 16-17 kts tops in most cases, although a carrier conversion would be light so should get a bit more. Whilst possible (like the British MAC ships which just stuck a flat top on top of a bulk carrier or tanker type hull) it’s need a lot of structural work, wouldn’t be cheap and would be slow and unweildy.

Would a former tanker be a option? While much of the internal space would be open. Surely, you could add decks and hangers………….better to add than to cut and remove!:rolleyes:

A picture from the Russian Nikolay Cherkasov. This is a RoCo ship as Turbinia described. She looks a lot like Conveyor in concept but apart from this picture I never found any additional information on this project/plan.

Exactly, the statement is politician speak for saying the exclusion zone is not a limiting factor and that the UK felt free to attack targets outside it. However since 1982 many people have claimed that the exclusion zone was some sort of self imposed limitiation of operations by the UK. Quite wrong.

From the time indicated, any Argentine warships and Argentine naval auxiliaries found within this Zone will be treated as hostile and are liable to be attacked by British forces. This measure is without prejudice to the right of the United Kingdom to take whatever additional measures may be needed in exercise of it’s right of self-defence, under article 51 of the United Nations Charter

Italics mine.

Just the relevant passage, I can’t be bothered to copy the whole announcement, hope this helps.

Sufficiently wooley to enable virtually anything to be done.

The advent of the F-35 Lightning II is going to open up alot of possibilities……………add a few Helo’s and any Merchant Ship could to turn in to a Aircraft Carrier in days…………:rolleyes:

No change since 1969, then. 😀

From the time indicated, any Argentine warships and Argentine naval auxiliaries found within this Zone will be treated as hostile and are liable to be attacked by British forces. This measure is without prejudice to the right of the United Kingdom to take whatever additional measures may be needed in exercise of it’s right of self-defence, under article 51 of the United Nations Charter

Italics mine.

Just the relevant passage, I can’t be bothered to copy the whole announcement, hope this helps.

The advent of the F-35 Lightning II is going to open up alot of possibilities……………add a few Helo’s and any Merchant Ship could to turn in to a Aircraft Carrier in days…………:rolleyes:

The US Navy conceived the ‘Arapaho’ programme inthe late 1960s. A container ship would be modified to permit testing of its suitability to operate special mission helicopters. The aim at that time was to allow a significant proportion of wartime convoy escort and sealane protection tasks to be performed by such ships, manned by USN reservists. The Arapaho concept involved an LPD-size flight deck 200ft (61m) long and 64ft (19.5m) wide, and a 4,000 sq ft (372m²) hangar large enough to accommodate four Sea King helicopters. The complete installation weighed 900 tons, and could be installed on a container vessel in less than 18 hours. In 1982 such an installation was emplaced on the 18,000-ton Export Leander, and 178 helicopters landings and take-offs were performed. In the following year the Arapaho equipment was leased by McDonnell and installed by Camel Laird at Birkenhead on the 27,900-ton MV Astronomer (subsequently remaned RFA Reliant) for tests in the South Atlantic. In efforts to exploit the sales potential of the Sea Harrier, which rested largely on its ability to operate from small, inexpensive ships, British Aerospace proposed the installation of ski-jump decks on commercial vessels, and the ‘Skyhook’ concept that would allow such aircraft to operate in the VTOL mode from ships without any form of aircraft deck.

Below MV.Astronomer, one of the ships taken up from tradefor the Falklands War, later converted to take aircraft, and after the war turned into RFA Retainer, the next picture. The picture of RFA Reliant making a bit of a splash is deceptive as the ship is far larger than it looks from this aspect.

As for the fitting of lifts and hangars… I’m surprised RFA Argus, which started life out as the container ship MV Contender Bezant, was dismissed here so quickly. The ship was requisitioned for service in the Falklands War and purchased outright in 1984. After a four year conversion at Harland and Wolff in Belfast the ship entered RFA service in 1988, replacing RFA Engadine in the aviation training role. Since then, the Argus has proven to be a versatile vessel, serving in many wars. It would be the obvious example of a conversion, including of cost and effectiveness.

See also: www.hazegray.org/navhist/carriers/uk_helo.htm

Not immediately to hand, however if memory serves me right the British official history ( an essential book if you’re interested in Falklands history and well worth the pretty steep price) has it as an appendix, I’ll try and dig it out.

The question of the 1982 exclusion zone is one of those things that is just picked up and since few reporters bothered to cross reference the original declaration becomes an urban myth. If people read the terms of the exclusion zone it quite specifically did NOT exclude military action outside the zone, however few media outlets have ever bothered pointing that little fact out:(

Out of interest, do you have the actual wording as I’ve never been able to find something that hadn’t been scrambled by the media, the politicians and more recently the web apart from something I read at the time.

Also, do you remember if the attack on the Hercules was reported much at the time, its just the only time I can remember hearing about it was on an episode of Have I Got News For You when they showed footage of what was apparently the Hercules being scuttled.

Hi Neptune, I’ll be off until the week after next for e-mail. What I would say is that Maersk were looking at older vessels, if that gives you a clue:)

Hard to see, but what you’re seeing here are a bunch of longitudinal strengteners and some moveable tween decks. They can adapt the number of decks and hence number of vehicles they can carry. If they are carrying cars, they can lower the decks and take a lot more cars. For trucks they require more height and they can pull up some decks to the ceiling and create more space between the decks.

As for lifts, I think a container vessel with its own gantry crane would be suited too. These cranes can lift over 20-30tons and can drive along the length of the ship. Normally they collect the big hatches you see below the containers. These hatch covers weigh some 20t too, they are very strong because they have to take some of the transverse strength of the ship. So for carrier operation you could store a few aircraft below these hatches and lift them when necessary.
Something like this:

And here is a RoCo which Turbinia seems to prefer 😉

You could use the back vehicle storage as a hangar with an entrance to the forward container deck if necessary.
Once again these would be Harrier carriers and hence no true carriers.

I’ll be waiting for that info Turbinia as I still haven’t seen a way to counter torsion with longitudinal strength members… But if the guys at Maersk have figured it out I’m pretty sure it could indeed work!

Quite, I agree, my point was aimed at the vocal lobby of mainly British critics who still claim sinking the Belgrano was a war crime and cling to the exclusion zone as vindication, when the fact they cling to the exclusion zone as proof it was a war crime proves they have never actually read the British exclusion zone terms.
In fairness, for the most part both countries did try to contain the war to the two belligerent nations and localised to the Falklands combat zone, and it is one of the features of that war that for the most part both countries acted in what by war time standards was a pretty decent manner. Certainly if you look at the amount of neutral collateral damage of most other wars, and the fact that rounding Cape Horn is still quite a busy shipping route it is quite marked how little damage was inflicted on non combatant vessels from neutral parties.

However, is it in any way legal to attack the shipping of a neutral nation, that is nowhere near the combat area, and which is not involving itself in any way with either belligerant nation? 😡

Note (from the legal brief):
“Respondent United Carriers, Inc., a Liberian corporation, chartered one of its oil tankers, the Hercules, to respondent Amerada Hess Shipping Corporation, also a Liberian corporation. The contract was executed in New York City. Amerada Hess used the Hercules to transport crude oil from the southern terminus of the Trans-Alaska Pipeline in Valdez, Alaska, around Cape Horn in South America, to the Hess refinery in the United States Virgin Islands. On May 25, 1982, the Hercules began a return voyage, without cargo but fully fueled, from the Virgin Islands to Alaska. At that time, Great Britain and petitioner Argentine Republic were at war over an archipelago of some 200 islands – the Falkland Islands to the British, and the Islas Malvinas to the Argentineans – in the South Atlantic off the Argentine coast. On June 3, United States officials informed the two belligerents of the location of United States vessels and Liberian tankers owned by United States interests then traversing the South Atlantic, including the Hercules, to avoid any attacks on neutral shipping.”

Or does being at war entitle Argentina to sink any ship of any nation they want, anywhere it might be, if they can reach it? 😡

At least the Belgrano was a warship of one of the belligerant nations!

The question of the 1982 exclusion zone is one of those things that is just picked up and since few reporters bothered to cross reference the original declaration becomes an urban myth. If people read the terms of the exclusion zone it quite specifically did NOT exclude military action outside the zone, however few media outlets have ever bothered pointing that little fact out:(

Turbinia, Interested in your comments as always. Assuming a container or container RoRo is the prefered option, how do they hanger any aircraft if they don’t have lifts ? Is it a case of fabricating a ramp and winching aircraft up and down it to the lower levels or is everything done on the very top level ?

Maybe if someone could post a cutaway image of the internals of a ship like this I might be able to visualise it better.

Good question, some of the plans involve fitting regular aircraft lifts. A container or container ro-ro already has the deck openings and structural rigidity is not a problem, and since the hatches are much deeper than any aircraft carrier conversion would need then space to install a lift is also not a problem.
The main problem in all these projects is cost. Compared to a CVF, or even worse, a USN CVN, these look cheap, but to get a meaningful comparison you have to compare against the price of a new build hull along the lines of HMS Ocean, ie. a dedicated warship type built using commercial techniques and to commercial class standards in many areas. Once you do that the costs are nothing like as good for a conversion, and even in terms of time to get a ship that would be truly useful (as opposed to just a flat top for emergency ops like Atlantic Conveyor) wouldn’t be a five minute job. I’ve seen the cost/time estimates for the Maersk projects and whilst they’ve obviously got good reasons for doing the hard sell on the idea even they recognised any customer would be a bit mad to go for it instead of a new build. The “L” class boats they converted for USN MSC were a company joke, they could almost (but not quite) have bought four brand new container vessels of the same capacity and speed for the price of each conversion. Like I say Maersk did well out of the deal but whether the USN got a good buy is a moot point.
One interesting thing is that there are several drop in point defence systems already available if needed, probably the best known might be the British containerised Sea Wolf VLS developed after the 1982 war.