Carrier Fuel Question

[HPL]

I was just wondering.

Okay, Aircraft Carriers need fuel. The planes and helicopters that are based off that carrier need fuel.

Do they both use the same fuel, or totally different types?

[whatami]

Most , I believe (but am not sure!) all of the US's carriers are now nuclear powered. I know that they do have fuel bunkers on board for the planes and helicopters. The carriers themselves however, need no external fuel source.

[Ale]

Totally different; the carrier uses fuel oil, while the planes use jet fuel, which is refined kerosene plus some additives.

[tomndebb]

Non-nuclear carriers are usually driven by steam where the boilers are fuled by "Bunker C," a heavy oil that is close to tar in consistency and must actually be warmed up to be piped into the firechamber for the boilers.

Aircraft, as noted above, use a variety of kerosene for turbojet and turboprop engines.

Back in the days of reciprocating engines (before turboprops), aircraft used high octane "av gas".

It is possible that a few non-U.S. carriers are powered by diesel-electric combinations, in which case they would run on a variety of kerosene called diesel fuel. I am not aware of any warships that actually use that combination, although it is increasingly popular in the merchant marine.

[First Amongst Daves]

Originally posted by tomndebb
Non-nuclear carriers are usually driven by steam where the boilers are fuled by "Bunker C," a heavy oil that is close to tar in consistency and must actually be warmed up to be piped into the firechamber for the boilers.

Aircraft, as noted above, use a variety of kerosene for turbojet and turboprop engines.

Back in the days of reciprocating engines (before turboprops), aircraft used high octane "av gas".

It is possible that a few non-U.S. carriers are powered by diesel-electric combinations, in which case they would run on a variety of kerosene called diesel fuel. I am not aware of any warships that actually use that combination, although it is increasingly popular in the merchant marine.

The Ukrainain carrier delivered to China a little while ago was a diesel/electric combination.

I also vaguely recall the HMS Ark Royal is a diesel boat, but would appreciate confirmation of that.

[Crusoe]

Originally posted by The God of Muesli Bars
I also vaguely recall the HMS Ark Royal is a diesel boat, but would appreciate confirmation of that.

All three ships of the Invincible class are powered by gas turbines -

The ship is powered by 4 Rolls Royce Olympus Gas Turbines, from the same family as the engines which are fitted to Concorde, giving a maximum speed of about 30 knots. The engines drive two shafts through the largest reversing gearboxes installed in any ship in the Western world. Designed and built by David Brown Limited, these gearboxes allow any number of engines to be selected to drive the ship according to the power and manoeuvrability required.

Electrical power, sufficient to light a medium sized town, is provided by eight Paxman Valenta Diesel Generators. The diesels and the main grid can be controlled from a central console and switchboard in the Ship Control Centre.

[county]

Originally posted by tomndebb
Non-nuclear carriers are usually driven by steam where the boilers are fuled by "Bunker C," a heavy oil that is close to tar in consistency and must actually be warmed up to be piped into the firechamber for the boilers.

Actually Bunker C is crude oil that has had most of the "good stuff" (gasoline etc) refined out of it, the "Bunker C" is what is left.

I don't know about use in boilers but the Bunker C has to be ~70 degrees to pump the the stuff due to it's consistancy.

(Oh yeah, it doesn't come out of clothes, very bad stains)

[KenGr]

The US carriers that were fossil fueled did indeed use Bunker C. The jet fuel is carried in tanks in the lower part of the ship and also serves as ballast. As the tanks are emptied of fuel they are refilled with sea water to maintain the ballast configuration.

[Desmostylus]

whatami hit the nail on the head.

According to the Navy, there are currently 12 and a bit carriers. (The thirteenth carrier only had its keel laid on the 6th of September this year).

Of those, only the USS John F. Kennedy (CV 67) and the USS Kitty Hawk (CV 63) are non-nuclear.

[Desmostylus]

I mean, as far as US carriers are concerned.

[Chicago Faucet]

Just to add to what has been said already, aircraft fuel is known internally as JP5. It is stored in vast reservoirs in the bowls of the ship, and would be pumped up to the flight deck in huge hoses to refuel the aircraft.

I spent about two years of my life floating on aircraft carriers. As I can remember from the 90's, our aircraft carrier would be replenished about once a month.

In a Carrier Group, there are anywhere between 8 and 12 ships, including the carrier, and usually two submarines. All of the other ships are lesser Destroyers, Cruisers, and Frigates. Once the Carrier Group gets to their destination, say, the Mediterranean Sea, we would just cruise in circles around each other and play war games. There were so many ships in the Carrier Group because atleast one was in port at any given time. The others basically ran as backup, protection, and supply for the carrier. The ships would be careful not to cruise too close to the carrier, but would be in constant communication with the carrier. On clear days, you would just see the silhouettes of the other ships on the horizon.

To see the carrier get replenished was quite something. Since this would be the most vulnerable situation for a carrier, a couple of the other ships in the group come in closer. The supply ship pulls up beside the carrier, and it begins.

There are three ways carriers get resupplied. Flight operations for the day are halted so that helicopters can "drop" crates and pallets on the flight deck. At the same time, a Yeoman or Bosunmate fires, what looks like, a shotgun with a softball on the end of the barrel, with a cable attached, over to the supply ship. About four or five of these are fired across the water. Then more crates and pallets are brought across the cable, hanging over the water. And this is the same way that fuel gets on the ship, via tubes and hoses that span the distance. This is how a carrier stays supplied with food, fuel, and all the random supplies a city would need to keep operating. The whole operation takes several hours to complete.

A majority of the US aircraft carriers are nuclear powered. The old diesel carriers are no longer manufactured, but the US must always keep one active. One of the reasons is because the carrier that is assigned to patrol the part of the Pacific ocean closest to Japan must adhere to their regulations against nuclear.

[starfish]

I thought Japan accepted nuclear powered ships and just asks that there be no nuclear weapons.

[KP]

Japan, which has no petroleum and no appreciable native coal, was hit very hard in the "oil crises" of the 70s. Today, 35% of its electric power comes from 17 nuclear power facilities. However, there have been a few tiffs over the docking of US nuclear powered carriers, not because of our safety record, but because of theirs. Every time the scandal racked Japanese nuclear industry has an accident or disturbing public revelation, they get nervous about our carriers. This happens more often than you might think: e.g. they had one of the world's worst meltdowns in 1999, and just a few months ago, public revelations caused them to take ALL their nuclear power facilities (over 1/3 the nations power) off-line for inspection.

On the subject of US nuclear weapons in Japanese ports: despite their public stance, they have had a an attitude of tacit approval since 1972. Of course, this have been subject to great fluctuation over the years, and the volatility of that "tacit approval" adds weight to public concerns in port cities' concerns over nuclear-powered carriers. The US must be expecially responsive, militarily and diplomatically, if they want the tacit approval to resume after a uproar.

[KenGr]

Originally posted by Chicago Faucet


A majority of the US aircraft carriers are nuclear powered. The old diesel carriers are no longer manufactured, but the US must always keep one active. One of the reasons is because the carrier that is assigned to patrol the part of the Pacific ocean closest to Japan must adhere to their regulations against nuclear.

Just to keep the story straight, the US fossil fueled carriers are not diesel. They have boilers and generate steam which runs turbines. They have both turbines which directly drive the props (usually four great big ones) and electric generators.

One interesting point is that the last WWII carrier (Forrestal) had 8 boilers, a pair for each shaft. Because of the available size of the early reactors and layout similarity, the first nuclear carrier (Enterprise) has 8 reactors. Later carriers have just two large reactors.

[Hail Ants]

It is possible that a few non-U.S. carriers are powered by diesel-electric combinations

As far as I know the only sea-going vessels that are diesel-electric are submarines. There would be absolutely no reason for a surface ship to be. Boilers make steam which spins turbines connected to the props (and nuclear powered ones just use a reactor to boil the water). Adding an electric generator/motor to the loop would be needlessly complex.

[Ale]

About the heavy fuel oil used for the boilers, I forgot to add that it´s actually used as another hull protection, it doesn´t burn easily and the tanks on the sides of the ship can absorb an explosion; such as a torpedo hit, for example.

[Xema]

Originally posted by tomndebb
[b]Non-nuclear carriers are usually driven by steam where the boilers are fuled by "Bunker C," a heavy oil that is close to tar in consistency

Nuclear carriers employ steam, too. The difference is the fuel they use to make it.

I'm a bit surprised to hear that carriers use Bunker C. I was in the US Navy more than 25 years ago, at which time the standard fuel was NSFO (Navy Standard Fuel Oil - somewhat heavier than home heating oil). The understanding at that time was that Bunker C was obsolete and either had been or soon would be phased out.

[tomndebb]

As far as I know the only sea-going vessels that are diesel-electric are submarines.

I assume you mean naval vessels in this statement. There are lots of diesel-electric freighters wandering the seas. In fact, I suspect that diesel-electrics power well over 90% of the freighters built since the 1970s.

I'm a bit surprised to hear that carriers use Bunker C. I was in the US Navy more than 25 years ago, at which time the standard fuel was NSFO. . .

I will admit that my statement was based on merchant marine experience extrapolated to the Navy. When I was sailing 31 years ago, we used bunker C and, since my ship was contemporary with the Kitty Hawk, I just figured the carrier used the same stuff.

[ nitpick ]

the last WWII carrier (Forrestal)

The Forrestal was the first from-the-keel-up carrier designed after WWII. The last WWII carriers were the Midway, Coral Sea, and Franklin D Roosevelt which were all designed and laid during WWII, but were completed too late to participate in WWII.
[ /nitpick ]

[KenGr]

I did a little searching around and found a few Ranger, Forrestal, etc. history pages that do state, in fact, that they were fired with "bunker fuel". To the tune of about 120,000 gallons per day when cruising.

I don't think the US Navy has much use for large diesel combat ships (just cargo and maintence ships and maybe some LSTs) but they do have some gas turbine technology in some pretty large ones such as the Spruance class destroyers.

[Joe Mahma]

Originally posted by KenGr
The US carriers that were fossil fueled did indeed use Bunker C. The jet fuel is carried in tanks in the lower part of the ship and also serves as ballast. As the tanks are emptied of fuel they are refilled with sea water to maintain the ballast configuration.

How do they keep the sea water from contaminating the jet fuel?

[KenGr]

Originally posted by Joe Mahma
How do they keep the sea water from contaminating the jet fuel?

That was something that always concerned me but the Navy guys told me it was no problem. Water and fuel (oil) don't mix and, before refilling they did a quick purge and rinse. In the open ocean, the seawater is pretty clean.

[whatami]

This makes me think of something else. What type of fuel do most of the freighters today use. Like the great big oil tankers or just the car carriers.

Is it

originally posted by tomndebb
I assume you mean naval vessels in this statement. There are lots of diesel-electric freighters wandering the seas. In fact, I suspect that diesel-electrics power well over 90% of the freighters built since the 1970s.

??

[First Amongst Daves]

Originally posted by Desmostylus
I mean, as far as US carriers are concerned.

The only other carrier I can think of is the Charles de Gaulle, France's sole carrier, which is nuclear and IIRC is stationed in the Med.

I have no idea at all about Russian carriers.

Does any other country use aircraft carriers? Australia did have one (HMAS Melbourne?) but retired it about 20 years ago. Australia was going to buy the Ark Royal to replace it, but the British changed their minds when the Ark Royal proved its use in the Falklands War.

[tomndebb]

World Aircraft Carriers List: Carriers Summary (As of November 26, 2001)

- - -

Ship Propulsion: From Oars to Marine Engines
Ship's propulsion layout: More than one way to get the job done
According to these sites, it appears that direct drive diesels currently outnumber diesel electric systems. Given that the advantages of diesel-electric has been known for decades--and that it has an analogous application in railroads--I am surprised at that statment, but I have no reason to doubt the claims of the two companies that actually manufacture the systems.

In any event, diesel fuel would be the most common fuel, regardless of the relative numbers of diesel vs diesel-electric. Steam turbines are a dying breed and reciprocating and universal drive steam engines are archaic, regardless of their fuel source.

[t-bonham@scc.net]

Originally posted by starfish
I thought Japan accepted nuclear powered ships and just asks that there be no nuclear weapons.

And even on that Japan was a bit lax about it.

It was common for people* to say that there were no "nuclear weapons" on a ship. Technically true, because there were only "nuclear weapon components" that had to be assembled to create an actual "weapon". (The assembling took about 30-90 seconds to complete.) Many (most?) nuclear weapons were never stored as a fully functional weapon.

And the Japanese government knew about this 'loophole', of course, but just ignored it rather than annoy a major ally and trading partner.

This is based on info from my brother, who served on a US carrier about 15 years ago. But I doubt if much has changed in this regard since then.

*People said this, not the US Navy. All US armed forces refuse to state officially whether any particular ship, plane, etc. does or does not have a nuclear weapon on board.

[Hail Ants]

There's an old British/Australian aircraft carrier for sale on eBay.

[Desmostylus]

Originally posted by tomndebb
Steam turbines are a dying breed and reciprocating and universal drive steam engines are archaic, regardless of their fuel source.

Not quite. If the fuel source is nuclear, what else can you use?

[Desmostylus]

Originally posted by tomndebb
Steam turbines are a dying breed and reciprocating and universal drive steam engines are archaic, regardless of their fuel source.

Not quite. If the fuel source is nuclear, what else can you use?

[Desmostylus]

Originally posted by tomndebb
Steam turbines are a dying breed and reciprocating and universal drive steam engines are archaic, regardless of their fuel source.

Not quite. If the fuel source is nuclear, what else can you use?

[Desmostylus]

Jeez.

[Crusoe]

Originally posted by The God of Muesli Bars
The only other carrier I can think of is the Charles de Gaulle, France's sole carrier, which is nuclear and IIRC is stationed in the Med.

I have no idea at all about Russian carriers.

Does any other country use aircraft carriers? Australia did have one (HMAS Melbourne?) but retired it about 20 years ago. Australia was going to buy the Ark Royal to replace it, but the British changed their minds when the Ark Royal proved its use in the Falklands War.

In addition to tomndebb's list below, many countries are working on aircraft carrier projects. The three Royal Navy Invincible-class ships are to be replaced by two 55,000-tonne carriers (named in November 2003 as HMS Queen Elizabeth and HMS Prince of Wales). According to sources, "[t]he carrier's propulsion system will be Integrated Full Electric Propulsion (IFEP) based on four gas turbines."