My early 20th Century (ww1/interwar/early ww2) alternate world has armoured airships (I haven't fully worked out the physics but I assume some sort of handwavium to allow armoured ships not just zeppelins).

Would 'wet navy' i.e. traditional ships, still be needed? edited to update to reflect comments thanks all Assume very similar to early 20th century tech expect flying warships. i was assuming more flying airships than 'ships' that fly. i am assuming that traditional ships still exist for bulk trade but i suppose that air freighters/liners may overtake for high value/low weight traffic.

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    $\begingroup$ Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. $\endgroup$
    – Community Bot
    May 10 at 9:26
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    $\begingroup$ I think we need more details about your world to answer, especially what are your airships, technically. Are they identically the same boats you had in water, or are they different? If so what differences are there, beyond flying? $\endgroup$
    – Tortliena
    May 10 at 9:31
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    $\begingroup$ A mix of wet-navy and air-navy occurred in real-life in the 1920s-1930s in the USA. Airships used their advantages in speed and invulnerability to submarines for scouting and secure rapid transport of high-value lightweight items and VIPs. During the 1930s, those roles were replaced by airplanes, but blimps were still used very effectively through WWII as submarine-hunters - their loiter time was a great advantage. $\endgroup$
    – user535733
    May 10 at 12:55
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    $\begingroup$ One could have asked exactly the same thing about submarines. Would they make a surface navy obsolete? $\endgroup$ May 10 at 17:28
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    $\begingroup$ As Demigan suggested, please edit the details into the body of the question - comments are ephemeral and not to be relied on to stick around for the long term. $\endgroup$ May 10 at 18:16

5 Answers 5



The air fortresses use armored underbellies and a deliberate all-or-nothing armor scheme that is set out in such a way that if shot at from below many many of the nacelles need to be damaged to force the airship to the ground - or water.

Most Cargo has bad stowage to transport fee ratio

While airships will be a good way to transport light cargo with high revenue rates fast (like mail, where a few grams with tiny volume earn a considerable fee), most other cargo has really bad ratios for $\frac {Weight \times Volume}{Fee}$. Even fragile material like porcelain is more economic to be transported by water!

Also, did you know that they had to develop special extra light porcelain for the Hindenburg because normal porcelain would have been too heavy?

Wet Navy supplies the Air Navy

Thing is, that these airships still need fuel, and shipping fuel is easiest and most efficient on the waves. The airships fly to rendezvous with oilers and supply ships, which also act as radio beacons.

Wet Navy offers SAR

The Air Navy is still somewhat fragile, and to support them, it is best to have dedicated, fast and mobile ships that go out and pick up the survivors from crashes. These SAR vessels are, due to a lot of the planet being water, of course water-bound and operate out of the support flotillas that act as waystations for the Air Navy.

Wet Navy has a lower profile

Compare the radar profile of an aircraft carrier to a flying aircraft of its size and you will realize one thing: To see the ship, it needs to be above your horion. A Japanese Flattop like Ryūjō has only a height of about 15 meters over the waterline. Assuming you are a radio station mounted on a similar height, the tangent to earth that allows you to see her is about 19.5 kilometers.

enter image description here

However, would that be a 15-meter aircraft flying with its belly at 200 meters height (Hindenburg's cruise altitude), the flattop can see the airspip appear over the horizon at 46.75 kilometers. enter image description here

If both are flying, and have their bellies at 200 meters, then the spotter on top of them can see the other spotter on 74 kilometers. enter image description here

So in effect, the smaller surface ships can get much closer to the enemy fleet before being detected.

Wet Navy has more Dakka

You can armor the airships, but you need to place much much more guns to fight of fighter aircraft as well as surface air defence. Surface ships only need to mount more and more anti-air guns because weight is not as much at a premium as in airships and you only need to put them on the upside, not 360° around the ship.

The Development might possibly forgo part of the development of aval artillery to 16' guns for many more fast firing multipurpose guns from the getgo, though I can see Yamato and Musashi engaging airships at about eight to ten nautical miles with their 46 cm Type 3 anti-air shells - while ineffective against bombers, against lumbering airships enveloping them in flaming shrapnel will prevent fighter launches effectively and might damage engines or rip crew off the walkways.


Yes there would still be a need for a wet navy.

For example an armored airship needs to be build to deal with enemies above, on the same level and below it so it needs guns facing everything. A battleship only needs to fire above and on the same level, which simplifies the design to "guns on top".

While theoretically such armored airships would be able to reach high speeds especially when using jetstreams high in the air (hindenburg did 130km/h without) the time to accelerate and decelerate would be bigger than the wet navy ships. So a wet navy would be able to react faster to changing conditions while a well-prepared airship raid could catch up and do its business quickly.

While modern tech lets us use airships without mooring masts and many people to land them we did in WWII. Technically you could cut down on time to bring in logistis because you dont need to land in the harbor but can land close to the target destination instead, but supporting it with traditional wet navy logistics is likely a good plan.

That said these things would be GOOD. A battle-airship flying at a few hundred meters would have more range than its water based counterparts, its harder to adjust aim when firing at these airships since you cant use the water spray to judge the missed distance (and good radar controlled weapons werent available), missile technology was less capable than torpedo's so its only vulnerable to other large caliber rounds, they would be able to function as artillery platforms above land and not be limited to the sea... but they wouldnt replace the wet navy.


Also although its been beaten to death, an aerial aircraft carrier could easily support your aircraft. Unlike the depictions in media or the use of the real-life Acheron aircraft carrier you could go up to a certain height and simply drop the aircraft down to launch them. This decreases the need for steam catapults and the risk of the aircraft crashing into the sea. Also in WWII climbing to the correct height was a time consuming task. Being launched high above the sea (or land!) is a great advantage. It also makes it possible to launch and land aircraft at the same time pre-modern aircraft.

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    $\begingroup$ "A battleship only needs to fire above and on the same level" - discounting submarines $\endgroup$
    – Bergi
    May 11 at 0:11
  • $\begingroup$ @Bergi the physics involved make it easy to drop/launch things from the deck to attempt hitting submarines, that isnt as effective for dealing with ships on the surface or airships below you. So I discounted it to prevent the answer from getting too long (for once). $\endgroup$
    – Demigan
    May 11 at 8:12

This question can be answered simply, based purely on the difference in density between air and water.

For any specific displacement, a water ship can carry 200x as much armament and/or cargo as an equivalent ship in the air. Unless you have anti-grav tech, then there are numerous areas where it isn't possible for the air ships to outperform the water ships.


In all likelyhood, the answer is "Yes, definitely", though it depends slightly on the nature of your handwavium.

While airships hold many advantages over a traditional Navy, matching the sheer bulk and durability of seagoing vessles requires a lot of handwaving. Like a lot a lot. Let's look at a few aspects that might give some idea of just how much handwaving is required:

The Hindenburg's empty weight was around 120 tons. A Queen Elizabeth class Battleship displaces around 33.000 tons of water. So you're looking at a difference in weight of a factor of roundabout 275, give or take. If you want your airships to perform similarly to the Battleships, they are likely going to require similar levels of weight. In the real world, airborne units faced much lighter guns than Battleships did (obviously), if we assume flying battleships we must assume them fielding battleship size firepower. These airships would also be large enough (and probably slow enough) for large caliber, land based Artillery to realistically hit them, directly. Armoring against that is very, very heavy, and requires a lot of handwaving.

While the Navies in the mentioned time period fought very flashy battles with dozens of capital ships and hundreds of smaller vessels, a very important task of Navies in warfare is related to logistics. Britan required a constant supply of resources brought in via ship, which was why the u-boat campaigns were so damaging to them. To take over all of this transporting duty would require a lot of airships. They would have to be incredibly 'cheap' to build in order to fill this role entirely, hardly any more expensive than a comparable ship in terms of carrying capacity.
Also, loading and unloading an airship is likely going to be much slower than a ship, though if you handwave enough they'll be able to 'land' properly, which might remedy this somewhat.

Storms on the high seas are a danger for seagoing vessels even to this day. During the world wars, they caused significant casualties. Airships would be much more vulnurable to adverse weather, and being able to operate in rougher, stormier conditions is something that would be a definite advantage of seagoing ships.

  • $\begingroup$ Actually airships are very well able to handle bad weather. In WWII there already were airships that made this trip (to and back without landing) and during the cold war with bad weather over the north pole the airships were the only nuclear early warning systems still able to operate in the area for several weeks. $\endgroup$
    – Demigan
    May 10 at 10:37


These airships are great - some kind of antigrav lets them float in the air despite armor plate. Literal lead zeppelins (well, steel perhaps). And they can go downwind quite fast.

Problem: they still can only propel themselves with fans, despite their massive inertia. The war is over before they get there. So somebody needs to lead your lead zeppelins.

So the zeppelin drops a line and a high-speed tugboat snags it as it drives past. The zeppelin is jerked into motion like a parasailer (parasailor?). It can veer far side to side, or swoop down and momentarily shut off its antigrav for immense crushing force, while its nimble tug dodges enemy artillery for dear life.


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