Underwater Archery Better Than Underwater Firearm

Capture

Sometimes, the most absurd idea can yield some fascinating results. The latest to fall into the category is Eastman’s Hunting Journal who took to experimenting with archery underwater.

At first, I thought it was going to be a miserable failure (especially considering bullet’s tendency to lose velocity in mere feet), but seeing the release, of the arrow continues towards its target with lethal velocity for significantly longer than a bullet.

Its basically a long flachette and its shape and relative lack of velocity allows it to move through the water without losing energy as quickly. For those looking for the scientific reasoning, turn to Andy Lemke, a physicist on Quora answering, “How much speed does a bullet lose when fired into water?”

It depends on how long is has been in the water, what the speed was when it entered, the drag coefficient for the bullet and the density of the fluid. The initial speed is entirely variable here. Are we talking about a little 9mm or a .50 cal round?

I can tell you however, the relationship between drag force, velocity and the density of the fluid. Drag force scales with the square of velocity andwith the density of the fluid:

Now ρ for water is about 1000 greater than it is for air. This means that the drag force will immediately increase by a factor of 1000 once a bullet hits the water. From that point on, the velocity will rapidly attenuate with every millimeter traveled, but you probably already knew that.



Nathan S.

One of TFB’s resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR’s, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.

Nathan can be reached at Nathan.S@TheFirearmBlog.com

The above post is my opinion and does not reflect the views of any company or organization.


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  • Giolli Joker

    Cool video, unsurprising result.

  • Blake

    Consider the fact that humans have been bowfishing for thousands of years…

    Let’s go get some Chesapeake snakeheads 🙂

  • junyo

    Isn’t this effectively how spearguns work?

    • wetcorps

      Pretty much. I’m not surprised.

    • J-

      Given how mulch a good spear gun costs and how cheap I can get a decent compound bow at a pawn shop, I’m gonna start bow hunting fish than buy a new spear gun.

      • iksnilol

        Some duct, broomstick and a compound bow and you have a kinda slam fire spear gun.

        NOTE: Please don’t do that, I wouldn’t be surprised if it blew up. Leave stuff like that to professionals such as RoyalNonesuch.

        • J-

          I figured next up would be a coffee can filled with tannerite in the middle of a lot of chum. Get back about 50 yds and let ‘er rip with something centerfire. Then just scoop up the fishies that float to the surface.

          • iksnilol

            Man… We should go fishing sometime.

        • Sianmink

          “professionals”

        • Zebra Dun

          Hawaiian sling, rubber tubing and a cylindrical piece of wood add a spear and ya got a spear gun cheap.
          Works giggin’ frogs also.

      • Tassiebush

        Prices are inverted here. Spearguns start $100-200 and compounds are $450+

        • J-

          I got my first compound bow at a Pawn Shop for $60. It was a #70, double cam Bear. I had to add a set of sights and a new arrow rest but it came with the stabilizer and quiver. Worked well for a poor college kid for quite some time.

          I’m not taking a new bow into the drink, but I don’t think I need it to be really fancy for a 10 yard shot under water. Another $60 pawn shop special would work nicely.

          • Tassiebush

            Haha it just struck me what a dumb idea it would be to use a New bow for that! Yeah that pawnshop approach sounds wise! I have built a kind of underwater slingbow using fat theraband gold band and homemade steel spears but then I impulse bought my speargun so it’s not been tested in water cos the speargun seems such a nicer fit.

    • Anonymoose

      And flechette/dart-firing pistols and assault rifles.

  • Tassiebush

    Good test of the idea with standard modern fancy bow set up. They’d probably get a bit more performance if they took off the fletches and used a heavier shaft.
    Regarding arrow vs bullets in water it’s quite comparable to what we see with boat hulls. If we ignore planing hulls which cheat by riding mostly out of the water (speed boats, some fancy sailboats etc). For boat hulls that sit in the water (displacement hulls) length is the main factor in hull speed. The longer they are the faster they’ll go for any given frontal area.

    • Just say’n

      Yup, the longer canoe always wins the race.

    • actually, it is the square root of the length. That is, making it 4 times as long cuts the drag by 1/2.

      • Tassiebush

        Great clarification there! I’d forgotten about the 4/1 ratio. Was unaware that submerged have own formula although it totally makes sense.

  • Major Tom

    And that’s why the APS underwater rifle uses those little flechette style bullets. Regular bullets don’t work that great underwater.

  • Phillip Cooper

    Very interesting, even if it does replicate a speargun.

  • TheNotoriousIUD

    Good thing he wore his baseball hat.

    • Bill

      Results would have been a lot better if it was backwards, with a fish hook run through it.

  • Bill

    Besides the fact that it’s essentially the same principle as as a spear gun, I can’t imagine swimming with a bow, but there is also a lot of stuff, like a long string, cams, cables and such that are all going to interact with water, and not help things work. Try it with a recurve, longbow, and a couple crossbows and see what happens.

    This is important stuff, given the whitetail population explosion, eventually they’ll go amphibious, and bow season is way longer than gun season. Now we need underwater tree stands and some way of drinking beer while submerged.

    • Rock or Something

      Damn amphibious deer…

    • Blake

      Yeah, we have to keep the population under control lest they start getting hit by submarines…

  • Vhyrus

    Anxiously awaiting underwater crossbow zombie fight scene in Walking Dead.

  • Capt. Obvious

    Dude in video has no choice but to hold his breath when he squeezes one off.

  • Mrdakka

    Is he wearing sunglasses underwater?

  • Yes we do–

    • Jon

      Ok, so what does the bow superior to it?

  • DL

    Drop the Boom. Grab the Floaters.

  • Zebra Dun

    Loyd Bridges plays Robin Hood on SeaHunt!

  • jcitizen

    KEWL video – cool music. Why can’t Hollywood do this?