Active Sonar + Marine Life

Originally Posted by Drebbel

Target ? Or the navy using their equipment and exercising on a contact they found ?

The way I see it is that if you are not going to attack it it was probably not a target after all and there was (afterwards) no need at all to use that sonar.

Every navy that has these systems which have such an effect on species that are so high on the list of animals the general public loves should be really worried and make a huge effort in searching for alternatives.

I apologize if I should have used the word 'contact' ISO target. I'm a SH3 guy and everything is a target.

As far as the plausability I don't think the scenerio is out of reason. Wasn't it a couple of months back that a report about a Chinese sub was alleged to have creaped into a US Carrier Battle Group? The reports of the Russian subforce being a wreck doesn't preclude the sortie of at least a few boats probing US defences.
China could also be probing.

I thought that tactics precluded the use of active SONAR under most situations. Letting the contact know they have been detected seams like one of those situations. No one can tell how long the contact was monitored for its passive signature B4 they were pinged. Its not called the 'silent service' for nothing.

As you know the book 'Blind Mans Bluff' is illuminating as to the deception inherent in sub sevice.

[Ishmael]

I would be interested if there are any marine life surveys taken from the early 1960's through the early 1980's. That was really the early heyday of high-powered active sonars like the SQS-26 models. There weren't any mass dolphin or whale kills from that time as I remember. The reason I keep hearing for such kills seems to be bacterial infections caused by compromised immune systems. I've never heard of acoustics being the cause of that.

[leeclose]

Can i point out a small problem here 90% plus of all sonar work is done passive. IE no emissions so i would love to see where the heck there getting there info from in all my years in Subs i only ever saw us go active once Reason*****classified*** and skimmers er cough surface ships prefer to list passive as well only real active stuff are dipping sona boays from those pesky bean cans with rotors and as loud and annoying as they are i dont see em frying a whale

[Kazuaki Shimazaki II]

Passive sonar is done extensively in the US Navy, I believe, because for a long time they had an acoustical superiority over their main prey - Russians. Most of the time you get to hear them, so why let them know you are hearing them?

If you have aren't sure of an acoustic advantage, your use of active will go up, hoping to create a less penetrable "buffer zone" - even if you tell the target where you are, hopefully it is harder for him to get within X miles, so at least you have some space to play with when he attacks.

With subs inching closer and through the background noise level of the ocean, active searching (not just occasional rangefinding) will become more common. You can play games with signal processing for awhile, but eventually there's just no signal that stands out above the randomness. At that point what's left is to hit your own sound waves into the water.

[SUBMAN1]

One thing I would like to point out - this is a minor problem as compared to everything else we are doing to damage the planet. Some of the energy spent here could be better served down in the Amazon or something.

-S