To be honest, in an engagement with a modern navy (hypothetically, the British, French, Russian, or Chinese navies), any aircraft carrier that comes under direct fire probably wouldn’t last longer that that. Despite the sheer bulk of the craft, they’re sorely vulnerable to attack; losing rudder control would substantially inhibit maneuverability, and losing even a single prop or engine would slow the craft down to a fraction of its speed rating; either would probably inhibit the ability to perform flight operations, which is pretty much the only thing an aircraft carrier can actually do. And, as the British discovered during the Falklands Island Conflict, it doesn’t require a first-rate opponent to do damage and make your life hell. Hence, why aircraft carriers (and capital ships in general) are always accompanied by a large complement of smaller craft whose jobs are to do nothing more than protect it and/or act as sacrificial decoys. If you could get through the rings of protection to hit a mast, you could probably wreck havoc with the deck and supestructure anyway.
Sam Stone’s response is exactly on point, and is an astute analysis of the problems with building a wind-powered aircraft carrier. Viability is a key issue; if it can’t actually perform launch operations (i.e. head up into the wind, provide a clear deck space for a runway, et cetera) then there’s no way to build one, period.
Now, you could certainly build a sail-power boat to launch balloons or small zepplins, but I don’t think these are going to stand up to even primative 20th Century airpower, even if you could arm them with the most advanced protective systems available. But launching powered aircraft off of a sailboat, regardless of how large it is? Not a possibility, and for the reasons Sam Stone lists.
In addition to Sam’s laundry list of flaws I’d like to add one: No source of auxiliary power for all of the extras that go with aircraft carriers or any majory ship (Yes, you could add a generator, but then why not just go whole hog and put in engines.)
(For the record though, during the second world war the vast majority of carriers peaked out at 15-20 knots at most)
During the second world war the US operated paddlewheel steamer aircraft carriers (only for training on the great lakes). Perhaps that is retro enough for the OP, given the problems with sailing ships.
Suppose you built a triple hull catamaran? The two outside hulls would have sailing masts (which would presumedly avoid the problem of off-center sails) and the middle hull would have an open flight deck.
I don’t see any in principle reasons why it’d be impossible. Obviously it’d never match the effectiveness of nuke or diesel designs, but a great huge cat using a “wingsail” design to minimize rigging and crew should be reasonably workable. You couldn’t move straight into the wind for flight operations, but you could run before the wind which would give you almost still air. Good catapult and arresting gear should take care of the rest. Mind you, powering the catapult is gonna be a bit of a bitch. You might wanna go STOL-only like the small Royal Navy carriers.
You don’t want still air, though; you want to land into a strong headwind, better to stall you quickly while matching speeds with the carrier deck. And when running with the wind you’re going to have your sails at maximum angle. Sure, you could run them wing on wing, but as any sailor knows, a straight-downwind course is asking for an unintentional jibe, and that would be seriously bad when landing the aircraft.
That’s if you’re running fore-and-aft sails. Wouldn’t have that problem with a barque, although the rigging might present a bit more of a challenge. And a square rigger’s fastest point of sail is slightly away from straight downwind.
Everybody’s talking about moving into the wind as if it’s required during launch and recovery. It’s certainly desirable, and aircraft carriers do it because they can. But as long as we’re imagining, why not a carrier that turns into the wind and stops during flight operations? (You lose the advantage of extra wind over the deck, but it’s better than sailing downwind.) Make the sails and rigging retractable, or have big openings at the bow and stern with the flight deck between them and another deck above for the sails.
It would be really impractical, and really dangerous, but that’s not the same as impossible.
Okay, I was just looking for an excuse to post one of my pictures.
Seems to me that if you have a cat with rigid wingsails on each side, you’d have the sails extended at maximum angle in opposite directions, and you’d be very unlikely to jibe. But I’m no sailor, maybe I’m wrong.
If you’re “wing on wing” (i.e. sails out to both sides) there’s a very strong tendency, especially in light or flukey winds, for a sail to suddenly jibe over, hence the use of a “whisker pole”, “spinnaker pole” or “jibe rod”. Jibe rods (for large craft) are typically made of some kind of carbon fiber composite for high bending strength, and even then they break not infrequently owing to the enomous stresses they carry. Unintentional jibing can also be very dangerous to the crew and the boat.
It would also take an enormous crew to handle conventional sails for a boat the size of an aircraft carrier. The triple deck “ships of the line” typically took a crew of at least a couple hundred just to manage her and keep her trimmed and fit, and fatalities were high. You’d need lines and sails of considerably higher tensile strength than silk, comperable to or exceeding the best synthetic high tensile fabrics today. Using cylinder sails or somesuch might be more plausible, but given the thrust to drag ratio I doubt you could make more than barely steerage way, and you probably couldn’t make an upwind course much past a beam reach. Even with the ridiculously deep and profiled keels on modern aircraft carriers they still have an enormous amount of wetted surface area. Even if you could head upwind, you’d need to keep the deck leveled; even with a massive counterweight or gyroscopic stabilization I don’t think it would be feasible.
As for turning into the wind and remaining still, I suppose that might be possible if you could shorten the required landing distance and/or extend the runway sufficient to land a plane (though you aren’t going to land a Tomcat or a Hornet this way), but that poses another problem; once you give up steerage way (i.e. the minimum amount of movement required to maneuver to boat) you’re at the mercy of the ocean, and she’s a miserable bitch to give the reigns to. Maintaining your heading without anchoring or using some kind of auxillary thruster is going to be impossible, and the last thing you want as a pilot is a runway that keeps changing heading as you attempt to land. And then once you complete operations, you’ll find yourself “in irons”, forced to backwind the jib sail to get any movement.
There’s a reason that navies long ago gave up on sail power (despite the brauvera and fun of beating Nature at her own game), and that’s because you have a very limited ability to control your course, speed, and attitude. An uncontrolled environment is the last thing you want when you’re trying to land an aircraft on something barely larger than a high school sports field. I just don’t think it feasible–even in concept–to do this for anything larger than a toy plane.
So that’s twice now you’ve responded to my suggestion as if I were proposing a single hull with conventional sails, when both times I’ve suggested a large cat with rigid wingsails. Talk of heeling and unintentional jibes? What gives?
I’d also question the necessity of being able to land Hornets or Tomcats. Is HMS Invincible not a carrier? She’s just a toy, an infeasible design?
Obviously a sail-powered carrier will suffer all the problems of any sailboat. She’d be slow and ungainly, and often at the mercy of the winds. I don’t see where the OP or anyone else thinks those basic problems are going to be overcome. I take the question to be something like “could you make a sail-powered carrier that could keep up with a squadron of Nelson’s navy?” Perhaps not. Perhaps my proposal would actually have sufficiently inferior sailing qualities that Victory could come out of drydock and sail rings around her. If that’s the case then I’d withdraw my suggestion, but merely saying that fighting sail are obsolete is hardly addressing the OP’s question.
What I was thinking in the catamaran design was something like this:
|
/ |
/ |
/---| -+-
______|_______
\ / \ /
V V
You could even have one side for launches and the other for takeoffs.
And a weight dropping catapult.
FYI The F6F at the low end of the wieght chart needed 450ft to take off:
Okay, let’s talk about a cat. You can’t make a standard two-hull cat significantly longer than it is wide lest you make it completely unmaneuverable. So you’ll be talking about a ginormous spread between the twin hulls. Cats are also not upwind creatures; their best point of sail is slightly windward of a beam reach, and performance rapidly declining from thence. This is a result of having essentially no hydrofoil arm from the hull; you could put keels on the hulls but then you’d lose whatever maneuverability you have. (Removable daggerboards are a possibility but you probably won’t be able to make them an efficient shape.)
If we’re talking about a vessel that you could land an ultralight aircraft on then this is possible; heck, you can practically land one of those atop a small building by stalling on the landing. But something large enough to land even a light aircraft, much less a plane useful for combat? The thing would have to be so huge that generating the lift necessary to even maintain steerageweigh would require massive sail area (be they fabric sails or wingsails), and the jibing forces (even on rigid sails) would be correspondingly enormous. At any rate, I doubt you’d be able to cram this all on the deck along with a clear space for a runway.
The HMS Invincible is what is now termed a light aircraft carrier, although the Navy folk I know still refer to it by the traditional nomenclature of a “through-deck cruiser”, indicating the origin design as a cruiser with a clear deck space for vertical landing. By this definition, an ASW frigate is also an “aircraft carrier”, although neither of them are fit to conduct flight operations for horizontal landing. And you’re not going to mount sails to either of these things and get them to budge. (I’ll also note that Invincible’s lack of horizontal landing operations and the subsequent very limited range and capability of the Sea Harrier (<3000kg payload capacity, <1200km max range) made what should have been a modest effort to defeat a much more poorly equipped Argentine Navy into a major conflict in which the British lost much more than the Argentines.)
I still think the idea of a sail-powered carrier nonfeasible in any practical sense of the word.
Note that:
The sponsons don’t need to be the same length as the hull
The deck can be longer than the water line length
Catapults / arresting lines can make a short deck effectively longer
I might take some of the F6F specs and do some math…
By the by, I was playing around with some concepts tonight, and I came up with this. The hull in the center is of about the same size as the Thomas W Lawson (400-odd feet), and the flight decks are about 400 feet long, each (about 100 feet short of the deck of the USS Wolverine. The idea being that the ship could tack at an angle into the wind while keeping the flight deck straighter into the wind, and maximize the distance between flight deck and the ship’s centerline and sails. Eh?
Of course, even with my limited knowledge, I can think of at least two or three reasons why this configuration “might” not work. (Like issues of structural stability, or the fact with slow enough aircraft and/or a catapault of some kind, you wouldn’t NEED to launch into the wind.)
The angle you have those decks at would require the vessel to sail much closer to the wind than it would be capable of doing to have the runways straight into the wind. You’d need an angle nearer 45 degrees.
Even if you achieved the necessary angles, that doesn’t mean the aircraft would be landing straight. It would have to be crabbing something chronic in order to allow for the fact that the vessel would be sailing across its flight path. I leave it to the Board pilots to say how hard that would be to do
I could probably try to figure out and fly it on a simulator, but I’d have model the ship, then futz around with getting the right aircraft, weather settings, etc. Not technically impossible, but a royal PITA. Blast.
No different from landing in a cross wind, and a sail powered boat isn’t going to be going very fast at all. Ideally you’d have the deck angled such that at an average wind speed the combined movement of the vessel and the wind would result in a wind straight down the deck.
