So, Blue Submarine No.6. Other than the nightmare-inducing CGI, it's also notable for being furry/scalie bait, complete with the fish lady, Mutio.

Most of this bait is thanks to Dr.Zorndyke, a brilliant genetic engineer, who decides that it's time for humanity to be replaced and orchestrates a polar shift to flood the Earth's coasts, killing billions, and we can't even sell their now underwater apartments.

So, Zorndyke also has an army of hybrid creatures, including the Musucas (see pic related for more info). Musucas serve as transport for the Water Spiders, nimble mechanized troops that, along with the Ghost Ship, seem to be the primary offensive force. We know little about Musucas, but they were grown in underwater "cultivation tanks", near one of the poles. They are sentient and sapient and capable of verbal communication and probably have organic sonars as well.

enter image description here

This is what happens when you max-out Google-fu. Here's a video of one, though it has spoilers, so...

But, would that be workable in a realistic setting? Musucas aren't designed to engage in direct combat and when they do, the mortality rate is 100%, though they can score kills. Their role is transportation, the question is what (if any) advantages would such bioships have over modern, conventional waterborne military vehicles (larger ships and submarines)?

  • $\begingroup$ your two biggest problems are feeding it and buoyancy, air filled chambers will need a lot of heavier than water weight to counter balance. . $\endgroup$ – John Jul 26 '20 at 2:09
  • $\begingroup$ Radar engineer: "Sir, something big is approaching fast and I think it is drunk!" $\endgroup$ – user6760 Jul 26 '20 at 9:14
  • $\begingroup$ @John I think algae will be good enough. $\endgroup$ – Mephistopheles Jul 26 '20 at 9:39
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    $\begingroup$ If you are going to try to have it feed on its own you have the issue that it will need to spend most of its time feeding, and keeping in mind a whales feeding mechanism takes up nearly half its body. algae is not evenly spread across the ocean, it will need to stay in warm fertile waters. $\endgroup$ – John Jul 26 '20 at 13:24

Bioengineered is almost another way of saying "based on nanotech". So whatever those advantages and disadvantages that entails which includes pliable materials, distributed systems, and superior system integration.

One of which should be (if you so choose) superior senses and situational and structural awareness since you don't have a hull made of a single material, but can have sensory organs embedded throughout.

Flippers and undulating bodies (high Reynolds number propulsion methods) also have a number of efficiency, maneuverability, and stealth advantages over propellers.

With these two things combined, you should be much better at navigating crevices and canyons.

Another potential thing is with the pliability of organic structures, you might be able to constrict and reduce unused interior open spaces on the fly which would provide an adaptable method to increase buckling resistance against water pressure. I'm imagining something like an automatic door, except it's an automatic corridor that opens up in front of you and closes up behind you as you walk.

Would be useful for immediately isolating leaks as well. You might also be able to absorb the water out of any room rather than need a discrete pump or anything like that.

Potentially it could refuel, reoxygenate, and desalinize in-situ though nuclear submarines can also do these things (or simply don't need to).

  • $\begingroup$ definitely quieter, although it should be possible to pick up their active sonar like a whale. $\endgroup$ – John Jul 26 '20 at 2:10
  • $\begingroup$ Why do you claim that it's almost always based on nanotech? $\endgroup$ – NomadMaker Jul 26 '20 at 6:04
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    $\begingroup$ @NomadMaker Because that's what biology is as we know it: a naturally occurring form of nanotechnology. Look at the molecular machinery of how cellular division, bacteria, viruses, DNA, ATP, hemogoblin, and proteins all work. It's all a form of nanotechnology. Their function is based on very careful construction of atoms into molecules into specific shapes running around doing things, manipulating atoms at a time. What's the are viruses and bacteria if not a form of nanite? You are a lumbering machine based on nanotechnology. $\endgroup$ – DKNguyen Jul 26 '20 at 6:38
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    $\begingroup$ Based on really hard to program, utterly unreliable nanotechnology that sometimes decides to just not work for no reason at all. $\endgroup$ – Joe Bloggs Jul 26 '20 at 7:18
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    $\begingroup$ "biotech" and "nanotech" are often just similar flavors of applied phlebotinum $\endgroup$ – Dragongeek Jul 27 '20 at 13:25

I can think of a few reasons they would be better. Please note I haven't seen the video that has the creature in it.

  • if they get injured but not killed, they can heal with enough time rather than needing replacement parts
  • they can find 'fuel' wherever they are as opposed to finding gas(nuclear submarines don't need this though. )
  • They probably have better maneuverability than traditional submarines
  • the surface of the water, even when calm, is a very dangerous place for a submarine. depending on your creatures tolerance levels, it might be less dangerous.

A modern submarine, even a non-nuclear one, costs billions and requires a shipyard with hundreds of workers and many years effort.. A bio-submarine costs whatever plankton etc you need to feed it on while it grows.

Hence there are only a handful of submarines but you can have as many of the bio version as your ecosystem will support.


There already are bioweapons. Horses have been used for a long time.

Need I make it clear, the reasons these arent used:

  1. You need humans on board to control it. Large animals are dumb. That means most sea travel is out of the question because sea animals prefer to be underwater, and that would require extensive oxygen and energy supplies. Oxygen machines are about a kilowatt. If a blue whale is 1000 times heavier than a human who has a useful output of a few watts, then using metabolic scaling, even the whale would struggle to provide enough energy to support a human. You would need a power system anyway and it would end up being larger than the animal.

  2. Assuming your controlled horse, whale or whatever has a human available to ride it now the problem is maintenace. Horses were replaced by cars because of both speed and maintanability. Cleaning up and feeding an animal is a frequent task while maintaining a submarine only happens when it is in port. Even if it is equally time consuming, machines have a more controlled maintenance schedule that disrupts operations less.

  3. The obvious reason is speed- no animal has the kind of speed that machines do. Whales go about 12mph while submarines can go several times that.

As for stealth, whales have an IR signature visible a good distance away, so they would need the same coatings military weapons do for the same effect. And you would need humans to control it so you need machines anyway.

On purely a cost front, diesel and uranium are cheaper than biofuels, so that's an additional problem. The cheapest of all is a sailing ship which has no fuel. You can use plankton but that severely limits the size of your fleet.

So control, scheduling, speed, and cost are the reasons machines were picked over animals.

  • $\begingroup$ I see. No.1 isn't a problem for the aquatic non-humans in Blue Sub. For no.2, horses were selectively bred, not designed top-down to be a method of transportation, which changes some things. I don't say the point is entirely unapplicable, though. Also, thanks for that horse article, it will make for a nice question. $\endgroup$ – Mephistopheles Jul 29 '20 at 20:18

Stealth. Stealth. Stealth. It's about all about the Stealth.

A submarine's primary and main advantage is it's inability to be detected. Modern-day military submarines go to extraordinary lengths to enhance this capability, as for a submarine there is nothing worse than being seen.

Once detected, submarines are very vulnerable - a simple torpedo (nuclear or not) or modern depth charge would destroy it easily, as it cannot go very fast, cannot manoeuvre and it has only very limited countermeasures.

It is such that even knowing the general 'area' of a submarine means it defences are compromised. Dependant on range, Active Sonar systems can detect modern day submarines easily. In fact, modern-day submarines use 'Passive' Sonar (ie. sonar that does not send any signal) because to send any sonar signal would reveal its location. Efforts include Anechoic tiles to absorb sound, submarine shapes designed to reduce turbulence, dampeners utilised to reduce engine noise.

A submarine that does not have the advantage in stealth may as well be a surface ship, which are much cheaper and safer - or an aircraft, which are much faster.

An organic submarine would therefore be better than a mechanical submarine if it enhances its stealth capability. There are many ways to do this:

  • Organic passive sonar signatures can confuse detection systems. The software on a listening device may require upgrading and testing to adapt to the organic signature of your creature, giving it a short but vital advantage before the software is upgraded (perhaps your creature can alter its acoustic signature further if this happens).
  • Propulsion is one of the major ways to detect a mechanical submarine. Propellers create rythmic pressure waves (or a 'wake') which can be detected. Your organic creature may use much slower, smoother sideways movements to propel itself forward more silently and with little wake.
  • Any metal on submarines can be detected by specialised aircraft. This is a major strategy of Anti-Submarine Warfare. An organic creature, however, has no metal components that can be detected via Magnetic Anomaly Detection, and this alone would severely disrupt ASW destroyers and aircraft techniques to detect them.
  • Another aspect of warfare is also intelligence and defence procurement. In other words, Stealth of a submarine is not just in the object itself, but in the secrecy in which it is designed, the disclosure of any manufacture of its parts. These are closely kept secrets. By having (presumably) a breeding programme for your creatures in a single location, you reduce the potential leaks of intelligence that sometimes occur with thousands of subcontractors and suppliers that would severely affect the ability of the submarine to remain secret. Perhaps your breeding programme could occur in just limited underwater pens, known only by an elite few.
  • $\begingroup$ Soooo, Blue Sub got most things right? $\endgroup$ – Mephistopheles Jul 26 '20 at 14:20

The idea of bio-ships is old in SciFi. One of the better examples from my generation was "Moya" from the TV show Farscape.

Advantages? They can heal. They can react. They can maneuver.

Disadvantages? They can be poisoned, infected, disabled more easily, and killed - all of which (pro and con) were considered during the program's run time.

Disabled is the most contentious. But a living thing is worthless without all those nerves and a brain that keeps a sense of self-preservation going. In other words, the creature must necessarily feel pain and react to protect the entity based on the nature and severity of that pain. This is a massive disadvantage — and the more you remove it as a reality of a biological ship the less you have a biological ship and the more you have a wooden or steel ship that's just a bit more squishy.

However, the only answer to the question "would that be workable in a realistic setting?" is NO! because we don't know how to build bioships and therefore have no experience with what could go wrong. We literally have no way to realistically judge the answer without you completely describing what a "realistic setting" is.

As for advantages. @Flox is right that stealth tops the list (maybe, as I think about it, you still have heat, motion, displacement...) but you also have...

  • Fuel, the bioship can eat like whales by straining shrimp, etc. You wouldn't need to bring fuel along. (Disadvantage: rather than fuel tanks you have a digestive system, which can result in indigestion.)

  • Depth, I can imagine a biological ships achieving greater depths than beer cans.

Additional disadvantages:

  • Putting hard, rigid things inside a biological entity tends to bruise, cut, etc. the biological entity. This means you don't really have rooms with hard floors and walls. You have cavities that must accommodate the motion of the creature. Moving people around might actually be a chore.

  • Cells decay, die, and even rot. There would be no cavity that wasn't constantly shedding cells in one form or another. Yuck.

  • Defecation, which (unlike electricity-powered subs) would be pretty easy to track.



Vision: while we think of sonar as clicks-and-returns, or passive listening for voice patterns, dolphins can actually "see" for miles by broadly illuminating a space and listening to the reflected sound.

enter image description here

Scientists have attempted to reproduce this, and generated this image of a diver. However, we know this reproduction isn't complete enough - dolphins have demonstrated the ability to discriminate between colors at depth.

We have side-scanning sonar that reproduces this quality of sonar details in 2D. To the best of my knowledge it hasn't been done in 3D.

Hearing/Touch: many aquatic animals have a lateral line system that allows per detecting pressure changes (very low frequency sound) < 100 Hz at long ranges.

Smell/Taste: sharks can detect chemical concentrations in a few parts per billion

Reaction Times

In a mechanical vessel, this information is processed by software and put up on a display for a sensor operator to interpret. This is relayed verbally (taking a few seconds to communicate and understand) (or electronically) to a captain who uses this low-resolution data to make decisions, which are reported back verbally (taking a few seconds) to pilots or weapons operators.

By contrast, in one integrated animal : the sensor operator, captain, and pilot are the same mind. Decisions are made in tenths of seconds, rather than seconds.


The typical fish (44 mph / 70 kph) is as fast as than the world's fastest submarine, the Soviet Alfa (76 kph). Some fish can swim at double this speed (80 mph / 130 kph) and literally be at their destinations before satellites notice they've gotten under sail.


The deepest diving fish can reach depths of up to 8 kilometers, with little risk of implosion. And they can dive quicky.


Invisible to Sonar

Like all animals, a bio-ship is mostly water. That means Sonar waves will travel straight through it rather than bouncing off a hard metal craft. This makes the bio-ship invisible to sonar.

Bonus Advantages

(1) Ship can function with fewer crew. It can both pilot and repair itself so fewer people needed to do this.

(2) The ship can navigate its way down a trench much more easily than a normal vessel.

(3) Fire Hazards: Fire is the worst thing that can happen in a submarine. Fortunately if your submarine is mostly made of water the fire does not spread so fast.

  • $\begingroup$ Aquatic life is neither invisible nor transparent to sonar, because if it were, fish finders wouldn't work and whales could not use echolocation to hunt. Softer to SONAR maybe, but not invisible. $\endgroup$ – DKNguyen Jul 27 '20 at 19:14

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