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May 11 16 7:11 AM
The cargo figures given for AOs and AORs are normally exclusive of their own bunker requirements, thus in the example you have quoted SUCCESS could go 4308 miles, offload, and return, although of course she would never do that. And, if necessary, most of them can rebunker from their own cargo supplies so she could conceivably have a range greater than that although, again, it is a scenario which would probably never occur.
So far as I know there are as yet no warships which are powered by a combination of a liquid fuel and LPG, although there are certainly one or two merchant ships which are. It may happen in the future although the damage control implications of carrying large quantities of gas would be considerable.
Other warships, escorts in particular, have a much lesser range and it would be typical in a task group on an oceanic passage for escorts to fuel every three to four days. Not that they would probably burn all their fuel in that time but it is normally considered good practice (and indeed it is safer) to have full rather than partially empty fuel tanks. One sometimes does get down, although most Navies set a limit to which you can go under ordinary conditions, 30% of burnable fuel remaining being a common limit. Further, ship stability is affected by the amount of fuel onboard so many warships, particularly in heavy weather, need to ballast when getting low on fuel. And, in that context and depending on how bad the weather is, low might be 50% BFR.
"Combined Diesel or Gas" (CODOG) refers to the engine types - diesel or gas turbines. Gas turbines will burn a variety of fuels but in the naval context they burn the same fuel as the diesels - F76, Marine Gas Oil (MGO) or Automotive Diesel Oil (ADO) depending on which has been bunkered by the ship. Aviation fuels (usually F44 AVCAT) are sometimes downgraded to propulsion fuels and used for bunkering when they degrade for some reason, but they are never deliberately embarked for that purpose.
The rules for the stowage of petrol ("gas" in US parlance) in warships are very strict - normally it has to be stowed on the upper deck in containers which can readily be dumped overboard. Even in amphibious ships it is quite normal for embarked force vehicles using this fuel to be defueled when on passage. However, most land forces use exclusively diesel vehicles these days. In the days when navies used piston engined aircraft which burn AVGAS, effectively a very high octane petrol, there were stringent rules about how the fuel was managed, stored and embarked.
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