Weapons for Mer-people

Question

Thanks to this question on undersea fortifications, I have begun to wonder about the kinds of weapons mer-people would use when fighting one another. Normally, mermen are assumed to use tridents, but I assume this is more of a cliche than an actual tactical decision.

So, given the fact that you are a half-man, half-fish in an aquatic environment, fighting against an individual with similar properties, what kind of weapon would you want to bring to the fight? Considerations should be made to 3-dimensional combat, the unique movement system of merpeople (tail propulsion), and the extra resistance of water instead of air. Optional consideration includes the added difficulty of fighting in groups/formations, though I plan to ask a follow-up question about what kinds of formations mermen would use. Also, I would like to know about what kinds of armor mermen would use to combat these weapons, though again that might make this question too broad.

I am mostly concerned with a medieval tech level, or at least its undersea equivalent. I guess you can assume any weapons or armor could be forged by blacksmiths on land if that's a problem.

Answer 1

I think the simplest weapon would be a long spear used in a manner somewhat similar to a lance. The merfolk would couch the spear securely with both hands and possibly some sort of a harness and swim at maximum speed towards the enemy. At last moment they might try to swerve to avoid being hit while still trying to hit themselves.

Tactics might resemble tactics used by ancient triremes. They'd definitely would try to make flanking movements to get hits on the flanks with reduced risk of being hit themselves.

Galleys often ended up with boarding action. The analogue would be grappling with weapons. The weapon for that would be a long knife or short sword used to repeatedly stab the enemy. This would probably be the part that generates most fatalities.

The charge would require a helmet, possibly a rigid vest of some sort to protect shoulders and upper body. Possibly with attachment to couch the spear for charge. For melee, the off-hand forearm would be armored for parry. Maybe the weapon hand as well, but I don't see them using the weapon for parry.

So they'd circle around each other for a while for advantage, charge with spears set, and then resolve things in brutal melee with long knives and grappling. Minimal armor would make it brutal and fatal. I'd assume most battles would be won by the losing side losing its nerve and trying to run. (Or swim.) So units not breaking would win battles.

Answer 2

The problem with using traditional melee weapons as a merperson is that there is really no way for you to obtain purchase underwater, thus you'd have no leverage necessary to effectively swing/slash/thrust a blade. As a merknight, your best bet for fighting with traditional weapons would be something like jousting. In this case, a trident actually isn't such a bad idea.

However, as they spend most of their time underwater, it seems like a merperson would be more adroit in the use of their tailfin, not to mention that it must be the most muscular part of their body^{citation needed}. Arms may be somewhat useful underwater, but I just don't see how a merperson's upper body strength would be anywhere near as useful as their lower body strength.

My idea, as it is, is to attach something like a tessen to the end of a merwarrior's tail. The resulting melee fighting would look strange to the common landlubber, but awesome.

Answer 3

The physical properties of water are the key considerations here. Water is about 800 x denser than air, so projectile weapons and weapons which rely on speed to provide the momentum to deliver damage such as light swords will be severely hampered.

Short range projectile weapons are possible, so the merpeople could start combat with exchanges of "fire" from spear guns and similar weapons, but this would resemble firearms exchanges in the 1500's. Since fighting in water is 3 dimensional, we are talking about something similar to cavalry units of this period, who would form circles and ride past points in the enemy defense, each trooper firing a wheel lock pistol into the enemy formation, then riding out of range to change weapons. Formations similar to schools of fish weaving in constant three-dimensional patterns to fire or evade would be the analogue here.

Once the projectile weapons are out, then combat would become more "hand to hand". Thrusting weapons like spears would work well, but the inability to form walls or phalanxes (you would be constantly outflanked in all three dimensions if you assumed a static formation) would make combat resemble the individual duels found in the Illiad rather than clashes of bronze-clad warriors in classical times. If the combatants were to grapple, then daggers would be the biggest threat.

Body armour would not be a big thing since it would interfere with the mobility needed for combat. Protection of formations might be achieved through the use of nets along the flanks, but anyone losing situational awareness would risk getting entangled themselves. Other defenses adapted from that environment might include the release of "ink" into the water to mask movement, or having skin similar to that of a squid, to change colours to match the environment.

The use of chemical explosives would mean formations would have to be far more open (the shockwaves of an explosion would kill many merpeople if they were all close to the blast), and there might be some adaptation to shaped charge explosives to focus the shockwave in a particular direction, although there could be no "gunners" to serve the device; it would have to be aimed and fired either through timer or by remote control.

Other naturally occurring weapons could include bursts of concentrated sonar, or even electrical devices modeled after electric eels, although these would be more like shock batons than ranged weapons.

Answer 4

Spearguns
Spearguns use either an elastic band or compressed air to fire a bolt. If materials like this are not available, a crossbow will make a fair approximation. The weapon is high powered, but does not have an incredible range. There are a plethora of venomous/poisonous animals in the sea which can lend their venom/poison to these barbs. This allows for smaller and more deadly projectiles.

Knives
Large weapons are difficult to wield without proper stance. Small slashing and stabbing weapons like knives would be the best for close quarters combat. Again, venom/poison will make these more effective.

Fish Armor
Armor is difficult for a tail. It's not just a single joint. A good option for armor would be to be surrounded by a school of fish. The fish would act as a mobile and confounding barrier to incoming projectiles. A light armor could then be used to protect in close quarters against slashing weapons.

Answer 5

Assuming no fancy technology/biological stuff, some weapons I would expect:

• Long, thin spears, for charging, or defense against charges

• Crossbows - would only work short range, basically as an alternative to spears that works better for moving targets (waving a spear around is not practical)

• Rapiers, for short-ranged combat (defense, or after a spear charge)

• Daggers, as a left-hand weapon, or a fallback once spears and crossbows become useless

• Ink for concealment, either for retreat/dispersal or for obfuscating attacks (send several merfolk trailing ink clouds, in only one of them attackers are hidden)

• Nets with hooks, or strings with hooks, especially if you can get nasty nearly-invisible wires. This can be a good defense to leave somewhere, or to trail behind you if you're being pursued, or to hide in an ink-cloud.

Armor is also pretty interesting, because hydrodynamics become important, so armor that makes you swim more slowly would definitely be a problem.

As you mostly swim forward, a helmet and shoulder plates become much more important, but also, three dimensions makes peripheral vision much more important, so I would expect helmets that stick much more closely to the face, but leave the eyes open (glass visors would of course make things better, if the tech is there).

What could work would be combined forces of heavily armored spear-men leading a charge, along with rapier/crossbow wielders who are more lightly armored (for better peripheral vision) who protect the spear-men once a charge is done.

Answer 6

I think for underwater combat it would be useful to take a look at the different predator-prey relationships that already happen under the sea.

Consider the most popular, and villanized sea creature: the Sharknado.

Sharks will basically ram their target as they latch on and bring about death with their sharp pointy teeth. And so do most other sea predators:

Barracuda, Killer Whale, Sea Lions...

With the preference to being able to consume your target in one go.

I'd expect our mer-people would try to follow the same pattern - as some others have mentioned, it would pretty much look like jousting. There would probably be a strong preference for guerilla warfare - waiting in ambush and then striking when the enemy is caught unaware. Most other sea predators, like the stonefish do this.

One interesting thing about the water is how seals find their prey - by using sensitive whiskers. It seems reasonable that Mer-people would either evolve similar abilities, or cultivate companion animals the same way we do with dogs.

Answer 7

Armor

You would want some sort of metal protective layer covering the tail, however this should not impede movement much. I suggest Chain Mail as your first line of defense.

Very close quarters:

Your best chance to pierce the mail armor of your opponent will be using a Stiletto or similar weapon. You want it to be a stabbing weapon as swinging will increase the water resistance and decrease the strength of your blow. Chain mail was also designed to minimize the effect of swinging blows. If you stab you will have a better chance of piercing your enemies' armor. After they are bleeding and crippled leave them for the sharks.

Long distance

You could have some sort of coral ballista that fires harpoons. These harpoons will also be attached to nets that entangle multiple enemy soldiers at once.

Near surface combat

I imagine Mermen swimming near the surface and raining harpoons down on their enemies. They could also drop rocks and just about anything else to put their enemies in disarray.

Massive nets could be dropped to entangle entire battalions of Mermen.

Mounts

The best mounts would be Dolphins and Sharks due to their fast movement and strength. Dolphin riders would also benefit from the inherent intelligence of their steeds. Whale riders would be rare (why don't you try catching and training one) but I can imagine a scene in your story not unlike that in The Lord of the Rings when the elephant riders (forgot their canonical name - it's been a while) charge in and scatter the riders of Rohan.

Answer 8

Water resistance is going to be the biggest limiting factor.
Swinging a sword is going to be hampered by it, and any kind of club is pretty impractical for the same reason.

A spear/trident is really a good option for hand to hand combat because the thrusting of your arm has very little surface area, versus the entire side of your arm for a sword swing.

Another great option would be a speargun. You might be able to use a bow as well, though I don't know how well that would work, with the arms of the bow pushing against the water. The arms would have to be very thin to avoid water resistance.
EDIT: bows kinda work under water.

EDIT 2:
For very close combat knives would work, but also blades attached to the tail would be useful, and provide a lot of swinging power.

Also you could have fast swimmers dragging lines with hooks or blades on the ends to catch at enemies.

Lastly you could make a "blood bomb" to draw in sharks and start a feeding frenzy. You just wouldn't want to be close to where it burst.

Answer 9

I have to agree with some of the other people on here that tridents really don't seem like a bad option, as cliché as they may be. I feel like you'd be much more likely to see thrusting weapons like tridents or spears than anything swung like a sword or club. I've never swung a sword underwater, but it seems like the extra resistance from the water would slow it down a lot. Maybe a small, short club with a sharp, hydrodynamic shape could be effective though... perhaps some thing like a mere from New Zealand. In fact, I recommend looking at some of the other weapons used by Maori warriors. The shark-tooth club and stingray spear are of particular interest.

Answer 10

I might take a cue from nature, and the old frontier, and use some variant of biting Steel Animal Traps. One of the most effective predators in the ocean is a shark, and the shark's mouth is basically a natural one of these. The only barrier to these is how many of them you can carry, but smaller ones can be just as effective... You could even design a fairly effective melee weapon that bites...

Piercing weapons are also effective, and spring-powered tools work well underwater, so it ought to be fairly simple to construct some form of waterproof Nail Gun.

The last thing I'd want, in the water where actions are that much slower, would be for my weapon to drop from my hands, so in addition to having straps (and velcro?) to keep my weapons where I want them, I'd also have barbed gloves and bladed (shin/tail)guards.

As for tactics, one might consider most of the 3d tactics used in space combat sims like "Homeworld"; Wall, Sphere, X, and Claw are rather nice. More options can certainly be derived from these.

Answer 11

Take inspiration from the animal world:

Electric eels stun their prey with a very brief high voltage shock, using special organs in their body. As electrical discharges under water are omnidirectional, your mer-people could employ such an electric shock as a last ditch panic response.

Mantis shrimp use mechanical energy stored in their exoskeletons like a spring to pop a punch that moves so fast that a cavitation bubble follows. The cavitation implosion provides a substantial part of the damage inflicted by their punch.

The state of the art in human underwater warfare involves stealth torpedoes and very fast-moving supercavitating torpedoes that can travel a couple hundred miles per hour underwater by generating a bubble around the torpedo to reduce water resistance. So cavitation seems like a mechanic worth exploring.

Answer 12

I would bet on domestication and training of war animals: sharks, killer whales, dolphins, etc.

The tactics would be to surround enemy formation and push it to the surface. Even minor wounds from projectiles or melee attacks would draw blood and attract sharks and other predators.

See https://youtu.be/6zOarcL1BSc for how this works in real ocean.

Projectiles could be launched close to the surface so they don't lose speed as much and also to make them less noticeable and thus harder to avoid.

Also your fighters can wear stripes to be less detectable to the sharks, see https://youtu.be/DCIL2nvU4x8

Answer 13

Since not much is know about merpeople these are my thoughts:

I would assume that they would use found undersea items to craft weapons and armor, or occasionally, things found in shipwrecks. Items like sharpened coral or natural rock would work well for spear points and blades(of any length), and could be used to reinforce armor, but could get heavy and unwieldy if used for an entire suit of armor. I would imagine a more "leather" armor approach using woven seaweed (or other tough underwater plants, interwoven with strategically placed, shaped coral, rock or shells to protect vital organs). Possibly consider a "new" undiscovered plant grown by the mer-folk specifically for the armorcraft.

I don't imagine poison would be a good option, because once extracted from its source (animal, plant or synthetic) it would be nearly impossible to apply to any kind of weapon without the water washing it off or affecting an entire area, thereby polluting all of the environment in the surrounding area. There is no way to isolate a specific area for poison dispersal, so either an anti-toxin would be needed or a different approach. This would also have an effect on the surrounding flora and fauna of the sea, and I imagine the merpeople to be more eco-conscious than their land-dwelling counterparts and would decide on a better, more effective method.

Typically plant and animal based toxins need to be ingested or delivered directly into the bloodstream to be effective. Consider giving the merpeople some form of natural defense mechanism that utilizes toxins by touch or under their fingernails, used as a last resort, scratching the skin could administer the toxin or some other method. Maybe even a dissolving bullet/projectile, or false tip on a blade, that contains the toxin and is released once it enters an enemy body. Or contains a large enough dose to kill/paralyze an enemy, but small enough that if it dissolves on the ocean/sea floor, it wouldn't be harmful.

Any kind of traditional "gun" would be difficult to build for underwater use. Combustion is a key component of using a FIREarm and would not hold up to long-term use well. However, a more crossbow approach for projectile weapons could be considered. Using a somewhat heavy, sharpened object would likely be effective, but any projectile would not be very useful underwater unless a very great force could be used to propel it or if used for mid-range combat. Water, obviously, is very dense and creates much resistance when trying to move quickly, whether defensively or offensively. Spears would be the best bet for long-range attacks, or maybe some kind of spear-launcher, for added range.

As for mounts, I think that sharks and dolphins would be a good bet, but really, merpeople are equipped with the same mode of transport...are they really faster? Dolphins would be a more intuitive choice since they are more intelligent and would respond better to the interactions. Sharks, obviously, would be more lethal and would probably be used by more practiced, disciplined hands.

I hope these thoughts make sense, and I hope that you can create well-defined, believable world! Good Luck!

Answer 14

Since currents in the water a much more persistent that breezes in the air above, water-borne poisons would have a greater range and could be targeted with greater accuracy than their airborne counterparts.

Answer 15

The popular musical ensemble Dethklok has you covered with the lyrics to the smash hit - Murmaider. Its a song about mermaid murder!

• Knives
• Rope
• Dagger
• Chains
• Rocks
• Laser beams
• Acid
• Bodybag
• Shiv
• Pipe
• Hammer
• Axe
• Swords
• Saws
• Clubs
• Claws
• Hatred
• Anger

Reference: http://www.azlyrics.com/lyrics/dethklok/murmaider.html

Graphical presentation: http://www.youtube.com/watch?v=hqJKZVnNLT0

Answer 16

don't forget to consider the material of armor and weapons. It'd have to be bronze, as iron wouldn't last very long in salt water. Goes without saying they would have to be made by humans, so they would be obtained by trade, for pearls or whatnot.

Whales in war? You might know that killer whales, dolphins etc hunt fish schools by beating their tails and sending concussive shockwaves into them. It might be an effective use of a mermaid's tail, or a very large tamed aquatic mammal.

On the subject of mounts, why not Hippocampi, which is the mermaid version of a horse with presumably a much more powerful and muscular tail. They would not straddle them but lie across their backs secure themselves to their necks and arm with a lance and act as shock cavalry.

Answer 17

I think there could be some benefit to using the low visibility of being underwater, and/or the way light works underwater, to utilize surprise, camouflage, or distraction tactics to confuse and disorient the enemy.

While flash bombs may be too complicated for a medieval underwater-dwelling civilization, squid-ink, sudden reflections, and sand can also be used to disorient or distract. Wearing reflective armor and staying in a tight group while in motion will make it difficult for an enemy combatant to distinguish between targets. Like mackerel and anchovies (and zebras). At the same time, if your water is murky, wearing something that flashes and reflects is going to tell the enemy exactly where you are. metal weapons too, will reflect and flash, so consider non-shiny materials for those situations and emphasize camouflage and surprise tactics.

I know this question is about weapons, but defenses are a good thing to consider too. If you want shields, you will need ones that are shaped to be hydrodynamic to avoid slowing your fighters down while swimming. Same thing with armor. You'd also want armor that is lightweight for the same reason. Heavy things sink, which will slow down your combatants. You will probably want fighters that are patient, and then very fast and effective, that means lightweight weapons and armor. (Speaking of sinking, weighted nets are a fantastic idea for this and net guns are fairly simple in terms of engineering I think).

One other thing to consider is that sheathing/unequipping a weapon or shield is going to be different if your merpeople have fins in odd places. Dorsal fins mean no weapons/shields sheathed or held on their backs, and no straps or belts there either. Consider sheaths and belts worn on hips and arms or along the tail.