I was just checking up on unusual ship designs the other day, when I happened across an old favorite: the Thomas W. Lawson, a seven-masted schooner launched in 1902, and the largest pure-sail ship ever built.
Looking up the deck length—392 ft—I couldn’t help thinking; “Say, that’s almost as long as some of the earliest aircraft carriers.”
Hey…now that’s an idea!
Which brings me to my question: Would it be possible to build a sail-powered aircraft carrier?
I’m not talking about a Nimitz-level supercarrier, or even a WWII-level carrier’s capabilities. I’m thinking of taking a ship about the Lawson’s size and installing a flight deck long enough to launch and land primitve aircraft. (I’ll leave the military effectiveness of this to another discussion.)
The thing is, I don’t know a whole heck of a lot about sailing vessels, so I’ve got some questions about the whole scheme. Like, how far “off center” can you place the sails to increase deck space—could you build the flight deck as a complete extention over one side and leave the sail structure alone, split the difference and move the sails and flight deck both off center, or build the flight deck as a kind of catamaran addition? Would any of the standard sails hang over the flight deck during normal maneuvering? Could you sail into the wind enough to increase wind-over-deck to any usable degree?
Well, that’s…it, for the moment. All I can think of, anyway. Can anyone help me out with this?
There are a great many difficult issues that would need to be overcome. Many workarounds would be required to cope with problems avoided by central masts and conventional rigging. For example, mast strength derives from the mast itself in compression, and stays to triangulate the massive forces fore and aft and from side to side created by the sails. If the masts are to one side, how do you triangulate a force from that side? Another example: conventionally rigged vessels have sails, rigging and spars going in all directions. It’s not just a question of where the masts are. Even if (say) the masts are all to port, when you are on a port tack the sails will be out to starboard, potentially across your flight deck. There are answers and compromises that would get around these problems, I suspect, (though I can’t see why you’d bother).
A sailing vessel can’t come very close to wind at all. 45 degrees is the usual rule of thumb, but better is possible. In any event, they certainly can’t come close enough to the wind that an aircraft landing while the ship tries to sail into the wind won’t be crabbing something chronic.
Setting aside your request that is not be powered and setting aside the real world application that it is really inefficient, you might consider a Flettner ship with multiple cylinder sails and flight decks on either side. (Put it on a pair of cat hulls with the “sails” in the center and the flight decks out to each side.)
Of course, your “sails” would probably not survive the first cruise (what with planes jamming wings into them every couple of landings), but you might get a few launches/recoveries out of it.
You have one huge problem right off of the bat: sailing ships, pretty much by definition, sail in the direction of the wind or close to it. Thus any planes taking off would not get the advantage of taking off into a headwind that planes on modern aircraft carriers get. So either your plane is very, very long (to provide more runway) or else your planes have to be very, very light (to make do with a short runway and no headwind). Probably nothing heavier than an ultralight.
Or, you know, helicopters. Or Harriers, I suppose.
The last thing you want in a floating airport is a gigantic aerial obstruction sitting in the flight path. No thanks.
And to elaborate on the last message - aircraft carriers typically do 30 knots straight into the wind when conducting flight operations. That 30 knots can make all the difference in the amount of distance an airplane needs to take off, and it makes landing much, much easier. A sail carrier would not be able to do this - tacking 45 degrees into the wind would make for a horrible crosswind landing, and of course, you might not have any wind at all.
Also, the sails you would need would be immense. An aircraft carrier is a gigantic vessel, and much, much heavier than a sailing vessel of the same length.
Finally, your sails would be incredibly vulnerable to attack. A sail mast would last about 30 seconds in a shooting war these days.
A modern nuclear power plant is almost the perfect power source for a large military ship. Why on earth would you want to use something else?
Sam Stone, go back and re-read the OP for comprehension, please.
He’s not talking about the viability, nor is he seriously proposing use of such technology. He’s strictly talking about how one would build one, for the fun of thinking it through.
Have you sailed much Orbifold? Because although sailing vessels can"t sail close to the wind, vast amounts of sailing is done with the wind from 45 degrees off the bow to 45 degrees off the stern on either tack.
Yeah, I read it. Aside from my last comment about nuclear power, all the other stuff stands. These are issues that sit in the way of building a sailing aircraft carrier.
You could fudge a bit on both counts: insead of sail, wind turbines could harvest power to batteries. I’m told these are more efficient than sails, and not subjuect to wind direction.
And you could have an air arm of seaplanes that launch from a catapult but are recovered by crane after they land on the water. IIR, the Swedes had an aircraft carries in the 1930’s with over haf-a-dozen seaplanes but no flight deck.
I haven’t sailed much, no. However I was under the impression that tacking was not exactly a fast maneuver compared to sailing with the wind. Plus, a wind coming from those angles still wouldn’t be very helpful in getting an airplane to take off, unless the runway was at a very sharp angle to the keel.
From what I’ve been able to gather, modern aircraft carriers will travel at up to 35 knots into the wind to assist flight operations. Do you expect a sailing ship large enough to carry aircraft to tack into the wind at anything close to that speed?
Well, obviously there are huge problems with doing it for aircraft carriers, but consider it for more widely used, and larger, ships. . .container ships.
It’s probably still not feasible to stick a huge mast in the middle of one of those, HOWEVER, I was reading an article a few months back about the potential to hook a giant “kite” to a container ship. A kite roughly the size of a football field.
If the Japanese could build submarines capable of launching three seaplanes using a catapult (and smaller ones with only a single plane) and relying on recovering them after they landed close by in the sea, I imagine something could be worked out. Aircraft-carrying submarine
And could they not catapult them off the stern instead of the bows to gain assistance from the wind (and avoid the masts)?
In addition to all the other nearly-insurmountable problems, there’s also the problem that if your masts aren’t on the center line of the ship, you’re going to have to work a lot harder to keep the ship going straight.
Question about another consideration: Don’t the jets typically based on carriers have to have a huge amount of thrust, which combined with the catapult is necessary to get them airborne at the end of the shortened runway? Presumably the sails on this hypothetical wind-powered carrier wouldn’t be very happy to have such a hot blast in regular proximity.
(The OP specified “primitive” aircraft; would a Sopwith Triplane even have the juice to get into the air in such a short distance?)
Cervaise, yes. Sopwith’s don’t need a whole lot of wind to fly. In the 20’s, most of the major naval powers had platforms built on the top of their main gun turret to launch a biplane (with the aide of a catapult powered by a black powder charge) for spotting and search purposes.
The problems with sailing ships have been mentioned:
The masts and rigging take up a huge amount of precious deckspace. They also require a lot of manpower, even with motorised spar hoists, so you have lots of potential FOD around. (FOD is Foreign Object Debris, or Damage, depending on the context. For my purpose, more crew and more gear on or near the flight deck means more sources of potential debris to foul jets or props.)
The sails, masts, and rigging also will contribute to airflow problems across the area of the ship.
The pressure of the wind on sails causes a ship to heel to the side. An uneven deck makes for tricky airplane landing, launching, and even taxiing around.
The quickest solution I can come up with would be a sail powered seaplane carrier. The aircraft are stored in holds (called the hanger deck, nowadays). They are brought out to the weatherdeck on elevators, and winched/craned to the surface of the sea for take off.
The problems with seaplane carriers is:
The slow pace of flight ops. Not only does it take much longer to winch planes aboard than it does to crash land aboard, but also the ship has to slow down (or stop) while doing so, and can be left behind by the rest of the battle fleet.
More reliant on a good (calmer) sea state than flight deck carriers. A seaplane carrier will need to have a much lower freeboard (to make craning aboard aircraft as fast and safe as can be) than the current supercarriers. But a higher sea state will be dangerous to the aircraft, and slightly less so, but still more, dangerous for the ship, as well as restricting the opportunity for flight ops more than it does currently.
In short, to make your barge effective, it would need to be large.
To make your airstrike effective, as many aircraft as possible need to be launched against an actively defended target. Launch your guys in penny packets, they can get shot down much more easily.
To increase the effective range of your strike, and the strike’s time-over-target, you need to get it in the air, assembled into strike groups, and on it’s way as fast as possible.
This means all your aircraft should be assembled (“spotted”) on the barge for the strike before the first aircraft takes to the air. (That first strike aircraft launched is the one that will use the most fuel, and determines the net range and time-over-target your strike will have.)
The more aircraft you wish your sailing carrier to haul around, the bigger it’s flight deck will need to be, whether it is on the sailing ship itself, or on a towed barge.
If you just want a handfull of aircraft for recon, or “search and rescue” duties, then a “barge” is fine, I guess.
A large barge will slow a sailing ship down, and a sailing ship itself is not a speedy devil already.
EDIT: The British toyed around with towed barges (carrying a single biplane fighter for fleet air defense) in the late 19-teens. They dropped the idea, because the small barges they were using became dangerous at high speed, or in heavy seas. (Among other things.)