underwater explosives/ seal & sea lion deterrents

[Arthur]

I'm using the term "speakers" loosely! I expect they are a form of piezo electric device and need to be waterproof to thousands of feet. A submarine sonar array is many feet in each direction to get range and bearing on identifiable noises, how big the audio pinger element of a traditional asdic would be only the navy know.

[FlareLauncher]

If you are "successful" with your whale sounds, and combine them with underwater explosions - think Underwater demolitions - you may have success, but you MAY be visited by the 'other" S.E.A.L.S. ! I may advise you to be prepared for such an eventuality, and be cool. Those be some damned serious folks. Good luck!

Bill

[Sideburns]

If you are "successful" with your whale sounds, and combine them with underwater explosions - think Underwater demolitions - you may have success, but you MAY be visited by the 'other" S.E.A.L.S. ! I may advise you to be prepared for such an eventuality, and be cool. Those be some damned serious folks. Good luck!

Bill

Yeah, I have had large bore weapons pointed in my face before in the Puget Sound. My dad, daughter and allegedly I got a little too close to a large naval warship in Tacoma, but in actuality we just appeared to be heading straight for them at high speed. (our destination was on the other side of the ship)

[Sideburns]

In other news.... I did some more experimenting the other night. The explosive type deterrents can be attractants to other seals nearby, and should only be used if there is a giant school of squid that you're actively catching in danger of being immediately chased off by incoming seals. (all this is easily seen on our fish finder) If an explosive deterrent is used because a seal is hanging around you boat, it will likely call in more nearby seals. -like a dinner bell.

 

Titanium of several different particle sizes had zero effect on the brightness of the flash underwater when added to a BP deterrent.

 

The deeper the explosion happened, the more effective it was as a deterrent to those seals feeding under the boat. Long skinny tubes with heavier ballast added and/or longer fuses. Deeper blasts were more effective than larger blasts.

 

The squid seem to attack the jig/lures out of aggression almost immediately after a blast, even if being chased by seals!

 

And just to add fuel to the fire, a damn seal bit my jigs and snapped my line, loosing 3 of my favorite handmade jigs.

 

...havent played with underwater speakers .............yet........

Edited December 17, 2019 by Sideburns

[Arthur]

I've seen flat circular piezo electric tweeter drivers that take an electrical signal and make sound, but the biggest I've seen was about 3"dia. To get much audio frequency response I think you'd need more of them or a bigger array -and you'd need to waterproof them.

[dynomike1]

M-203 ought to do it.

[Sideburns]

Just a quick follow up. Although the small weighted black powder deterrents seemed to work somewhat, I was spending entirely too much time playing with explosives and had to almost continually drop them in the water to keep the seals away. Noticing that deeper explosions seemed to be more effective, i decided to try and propel the deterrents to deeper depths with a rocket motor! These were far more effective than anything else Ive tried!

 

10 inch long 3/4 inch id rolled paper tubes, pressed halfway with a simple black powder rocket motor (nozzleless and coreless) and the remainder filled with granulated BP. I made crude nosecones out of a 50/50 mix of plaster and cast iron filings to weight the nose of the "seal seeking missile" in the right direction.

 

After noticing seals on the fish finder (sonar) screen I would drop one over the edge. The visco bubbles until just out of sight, then woosh!, a cloud of gas bubbles. Back to the fish finder screen I watched it almost instantly shoot close to a hundred feet down before exploding. Perfect! The entire screen is completely blacked out for a few minutes and when the gas bubbles finally cleared up there was nothing left but squid underneath me. No seals in site! It absolutely scared the crap out of those seals! I caught a bunch more squid while eagerly waiting for more seals...

 

After a couple hours I got to use another one, and the results were the same.... BUT, the report failed to go off! & It was equally effective without any explosion! Looking forward to trying this out again next season to verify.

 

Thanks for all the suggestions guys!

[SharkWhisperer]

Surprised your nozzleless dont' just flame out under water if unprotected/uncovered. From description, sounds like plain fuel with a visco fuse sticking out of it. Really???

 

You need a rocket motor to get your boom-boom 100 feet underwater? Seems a longer length of visco would be a hell of a lot more cost-effective.... Oh, I see now that your N-values was precisely 1, until your second failure-to-explode, though considered successful. Depth charges are cool, I guess, but larger Ns and more detailed follow-ups would likely increase the "wow" factor with your fellow pyros. Good luck; I love calamari !

 

Interesting but seems maybe not the most effective approach to dissuading seals. Why all the trouble? Just toss a few Estes motors over with a fuse (and waterproofing) in them?

[memo]

but not near as much fun

[snapper]

now try it using whistle and strobe motors > start adding headers with flashing effects or strobe, even if they cato under water its still win win

[SharkWhisperer]

but not near as much fun

Bingo. I think you and Snapper are onto something here!!!

[FlaMtnBkr]

I was going to suggest a few things but as I got towards the end I see some were suggested and even tried.

 

I was wondering what a whistle rocket would do as they produce a long, shrill, slightly oscillating whistle. Also, a strobe might be effective? Even if it didn't scare them, it might be disorienting or maybe make it hard to see their dinner for a few minutes? I doubt there is much visible light at those depths but don't know what visibility is like or how far the light would travel? However, strobes can be finicky and the increase in pressure might cause a continuous burn instead of strobe or it may just not want to stay lit, so there's a chance it would require experimenting with formulas.

 

Another thought was a tube filled with thermite. It might burn hot enough to get bursts of steam 'pockets' that would quickly condense and collapse and possibly create sound or repeated pressure waves? Somewhat similar to what happens when you put a pot on the stove that's wet on the bottom and starts dancing around sometimes fairly violently depending on how full the pot is.

 

A way to possibly get around the laws dealing with explosives would be to have a small cutting torch and use gas to make your noise. Oxygen and acetylene in the right ratio makes a very loud and low/deep explosion and can even detonate under the right conditions. I know getting a container of gas to sink might require some creativity but you might not need very much. I've never tried to see what small containers do, but a gallon milk jug can be heard thru trees close to a mile away and probably more, and rattles the windows of nearby houses. A 12 oz juice bottle may be more than enough and is as simple as hot gluing a piece of visco in the lid ahead of time. Then set the torch for a good hot cutting flame and turn the gas off leaving the ratio unchanged. Put the torch in the bottle mouth, crack open the gas for a few seconds to displace the air, and then quickly screw the lid on. Don't know how MAPP gas and oxygen would do but small disposable bottles are much cheaper, smaller, and easier to get than an oxy- acetylene setup.

 

There are also propane noise cannons used for scaring birds away from crops. Don't know if one could somehow be used - and without going deaf.

 

Anyways, it's an interesting dilemma and these were just some thoughts I had and not sure how feasible they are or if they would be effective. Good luck and let us know if you do any more experimenting and how things turn out!