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**Pete7** · 18-07-2010, 13:32

I think the M80 is the quivalent of a UK Thunderflash used by HM Forces to...... well make a noise, provide a distraction and frighten when you need an edge over the enermy.

We used to give two demonstrations before issuing them to troops. A normal aluminium mess tin would be placed over the top of a thunderflash. After the bang the mess tin would be recovered from some distance away only it now resembled a very flat frying pan. The second demonstration woudl involve the use of an issue steel helmet. It would probably go 200 feet up and therefore required quite a safety distance so we didn't hurt anyone.

We did carry them with lead weights glued into the hollow handle to sink when we were diving, as a diver recall signal. Underwater the noise could be heard 1/2 mile away and always resulted in the divers returning to the surface.

I would venture that setting one off from a liferaft is more likely to attract any nearby sharks rather than repel them, if just out of curiosity. Still eating that shark could just save you.

http://www.hfmgroup.com/professional...erflashes.html

Pete

Ahnlaashock · 19-07-2010, 06:56

The Rolling Thunders were about three inches long and a little over an inch thick. They used a very think cardboard casing. Power level is hard to place by noise, but they make the ground shake, even going off a couple of hundred feet in the air. If you have ever been to the Arch fireworks display, you will understand what I mean. They can be heard 20 miles away when they go off in the air. I know, because we can hear them at the Arch, and I am over 20 miles away. Don't know what the explosive was. They could be purchased in Arkansas, but no where else I know of without a license, and that was the early 80's.

There is no doubt that anything in the water near one of them was going to be in trouble.
When I was a kid, Dad bought a new C-10 1969 Chevy truck right before the fourth. He and an uncle were sticking cherry bombs in holes in bricks, blowing them up. He had very carefully put his new truck on the other side of a big barn, where it was safe.
When we got done blowing things up, he went to put stuff back in his truck. About half of one of the bricks was stuck right in the middle of his windshield! It apparently got blown straight up and came down on the truck! Over a three story barn!

detav007 · 19-07-2010, 07:46

In Michigan, if you've got any farm or orchard you can buy explosives that are used to kill burrowing animals (groundhogs, moles, etc.). I've heard people call them 1/4 sticks but I don't think they are. Some have called them M100's but not sure as I've only blown them up, never bought any. They will launch a 5lb coffee can about 100-120 feet in the air but it holds together. I don't think I'd use it around a rubber raft unless the shark was already chewing on it.

David_Old_Jersey · 19-07-2010, 13:26

France had the best fireworks - usually had at least 1 annual school day trip when the boat home could have been vaporised by a stray cigarette

Not all lasted until Guy Fawkes day (for our international readers, that's 511 - the day we burn a Catholic

(nowadays only in effigy

).

stevensc · 19-07-2010, 13:54

If you "Google", shark repellent, there is lots of information on different trials and some products, even an acoustical one which must emit a sound which is supposed to run them off. It doesn't look like any of them are very effective.

I'd be more concerned with the "the sharks that swim on the land"
Steve

zeehag · 21-07-2010, 15:41

has anyone else found there are no stupid questions--just lots of entertaining ones????

Chipg · 21-07-2010, 17:10

The best shark repelent is called A-2, it is the scent of dead sharks, it freaks them out and they scatter very fast. Buy a tube of it if your worried about it.

**GordMay** · 22-07-2010, 05:05

Quote:

Originally Posted by Chipg

The best shark repelent is called A-2, it is the scent of dead sharks, it freaks them out and they scatter very fast. Buy a tube of it if your worried about it.

Where? “A2" Shark Repellant doesn’t appear to be commercially available.

A U.S. patent application filed in November 2007 by Eric Stroud of SharkDefense describes installing Lanthanide electropositive metals (magnets) into scuba flippers, a bracelet and a special belt that divers or swimmers can wear to ward off sharks
➥ Elasmobranch-repelling electropositive metals and methods of use - Patent Application 20070256623

Before stumbling on the magnet discovery, Eric Stroud of SharkDefense was working on a shark repellent made from chemicals extracted from the flesh of rotting sharks. Sharks are known to stay away from the rotting corpses of their brethren, so Stroud took that as a cue to research it as a possible repellent. Testing the solution referred to as A2, it had the desired effect.
➥ Repellent Could Save Humans and Sharks, Too - washingtonpost.com

➥ Repellents

➥ RepelSharks.com, Shark Deterrent Technologies

IceMan · 25-07-2010, 16:41

Gordy,
This is in regards to M80's equal to 1/4 stick of dynamite. As you already answered the question of powder types, aluminum based flash powder for M-80 as compared to TNT for dynamite. The flash powder is fast(3 aluminum based powders(which I will not name) were clocked at 1. 4655fps 2. 4687fps & 3. 4013fps. But TNT is 23,000fps and is used as the lowest base number for all explosive devices.)

But not to hijack this thread, I was wondering if liquid ammonia would be a good shark repellent? Oxygen breathing animals cannot exist where there is ammonia on the loose. Wouldn't liquid ammonia spread around where you were at disperse sharks? Of course, one must ask, "am I going to have a couple of bottles of liquid ammonia in my ditch bag".
WD

svcambria · 25-07-2010, 17:49

Quote:
Originally Posted by Ex-Calif

Actually it's simply a matter of posting, "I agree" after anyone posts.

You'll be right up there in no time.

(ask me how I know - LOL)

Quote:

Originally Posted by Aaza Dana

I agree.

And so I meet your agreements and add mine too...

Michael

John A · 25-07-2010, 19:29

This has got to be a slow day!!

M80's are small exploding devices used in the US Army during training in the early twenties and were about two inches long about 5/8" in diameter and olive drap in color, the fuse was equal distance from the ends. M80 or M8000 was their military designation., and this has been corrupted to include any large firecraker.

How the heck do you keep the matches and powder dry getting into and living in the liferaft?? There's several other things to worry about if you must live in a liferaft than sharks.