From: Tun Kai Poh [t_poh@hotmail.com] Sent: Friday, April 02, 1999 2:16 AM To: blue_planet@mpgn.com Subject: Re: [BLUE PLANET] - Cetaceans and sonar (snip) >Hope this helps, > >Jeff Barber >aka - Bataku's Ina informant >Biohazard Games It's fascinating as far as anecdotes go, buuuut... it doesn't give me any more of an idea of how to crunch up stealth and sonar ratings for cetaceans in vehicle combat, does it? Kai Poh, Malaysian Lagomorph Get Your Private, Free Email at http://www.hotmail.com *************************************************************************** To unsubscribe from this list send mail to majordomo@mpgn.com with the line 'unsubscribe blue_planet' as the body of the message. From: BIOHZD@aol.com Sent: Thursday, April 01, 1999 11:57 PM To: blue_planet@mpgn.com Subject: Re: [BLUE PLANET] - Cetaceans and sonar Hey Kai, You have some questions: >>>>Okay, the reason I asked has to do with the fact that we had an Orca character trying to sneak up on a hovercraft and a guy in a hardsuit. The players reasoned that the Orca would be _harder_ to spot on sonar than conventional military subs, because of "natural stealth" whereas I was thinking about the "biological interference angle >>>>Can cetaceans "turn off" their sonar? The question is in the form of sonar being used - passive or active? In 2199, both are much improved in terms of sensitivity and definition, but passive sonar remains a limited tool. Passive sonar only works if the potential target is making noise. Cetaceans can shut off their sonar at will and do it all the time. Orcas hunting dolphins and dolphins trying to escape hunting orcas play a tense game of echo hide-and-seek. They do the passive sonar verses active sonar tango, just like military subs. Remember too that cetaceans have very good eyesite (above and below water) and in even dim lighting, vision remains a valuable tool. An orca in "stealth" mode is essentially silent. Except for body sounds (as Jim correctly pointed out), and their admittedly limited bow wake, there is no noise for passive sonar to pick up. Even these unlikely sounds would only be very short range giveaways. Active sonar however, either on the part of the target or the hunter, is another story. In 2199, making loud sounds underwater is as good as shouting in church. By way of real example, a few years ago the US Navy declassified thousands of hours of sound recordings from their SOSUS system. You should hear these things - real live Whalesong Theogeny stuff. Researchers quadupled their knowledge about whale song and population distribution, just from studying these tapes. In fact, the Navy now admits the SOSUS net was useless for months after its activation, until they learned how to filter out all the background noise - primarily whale song, but also waves, crustaceans and fish. Hope this helps, Jeff Barber aka - Bataku's Ina informant Biohazard Games And then there's Greg Benage's Bataku story in the main book, where the Orca native chief and his warpod sneak up on a well-guarded underwater facility without being spotted... And another thing - can uplifted cetaceans "turn off" their echolocation to avoid having their sound pulses detected? This also came up in my BP game. The other problems included integration of an Orca into long-range travel plans, etc. Frankly, the number of cetacean-related game problems got so confusing that as a result of the 3rd Malaysian game (which I will get around to writing up as soon as I can) we shelved BP for the time being and are now doing GURPS World War 2 until I can fix BP's cetacean rules. Anyway, if Jeff could give us an official word on this (or better yet, real hard stats in an upcoming Undercurrents) this would be nice, hint hint... *************************************************************************** To unsubscribe from this list send mail to majordomo@mpgn.com with the line 'unsubscribe blue_planet' as the body of the message.