Thread: Proposed Test

I hate being a skeptic, but I are (gov conditioning)! But I always thought sonar was a picture of sound waves reflected from underwater. Air transmits sound waves but at a slower speed than water. If the air bladders in fish or air inside PP balls is what shows up, then our submariners are in bad shape as far a stealth goes. Sonar reflections may be more a function of shape and material density difference from water. IDK how it works, but do know that flat metal reflects well, flat plastic (from structure made of PVC siding) shows much better than round pipe. This being said, if you go over fish f***ts they show up, but then on sidescan you wouldn't get shadows if sound waves were transmitted through objects

CACHE, SONAR WAVES DO NOT TRANSMIT THRU AIR,I THINK I AM RIGHT,THAT IS WHY WE PICK UP AIR BUBLES AND IF TRANSDUCER COMES OUT OF WATER THAN IT WILL NOT TRANSMIT,YOU ARE RIGHT ABOUT THAT

Originally Posted by cache22

Sonar reflections may be more a function of shape and material density difference from water.

Correct....on both counts...

Shape ...in that the target's surface can be directing the sonar right back at the xducer (instead of bouncing off at an angle)....

Material density ...in that sonar sees the difference in density of the water and the target...

Rickie

Originally Posted by vic n

Kosmo and others who like to experiment-
I've been over on the "crappie cover" forum looking at some of the fish cover they build and install, because I'd like to do something at a local spot. The problem is these guys all say that PVC is about the same density as water, so it is basically invisible in the water to SI and DI. I was hoping that would be a challenge some of you might like to prove or disprove. Kosmo's pics showing ping pong balls makes me wonder if PVC will show up if it is closed up with air inside....basically a giant ping pong ball. I'm sure no one wants to try and sink a PVC thing that is completely sealed up, but what if each piece of cover had just one piece sealed? Would that show up? I guess if you wanted to see it on DI, you would want a horizontal piece....maybe 2" x 18" to show up and be distinctive. I don't know if you would want a vertical piece for SI, or if the same horizontal piece would be just as good?
What do you guys think? Has this already been done?

Here is a shot of a couple of PVC attractors.

Originally Posted by genec

CACHE, SONAR WAVES DO NOT TRANSMIT THRU AIR,I THINK I AM RIGHT,THAT IS WHY WE PICK UP AIR BUBLES AND IF TRANSDUCER COMES OUT OF WATER THAN IT WILL NOT TRANSMIT,YOU ARE RIGHT ABOUT THAT

Maybe that's why I don't hear so well!

LARRY, YOUR DI IS SHOWING EVERY POST AND CRAPPIES ON THAT SECOND-THIRD ONE,LOOKS GREAT

Well I may not get my test, but it was sure a fun discussion....thanks

Originally Posted by genec

LARRY, YOUR DI IS SHOWING EVERY POST AND CRAPPIES ON THAT SECOND-THIRD ONE,LOOKS GREAT

It took about 2 weeks for the crappie to show up and we caught a few. Then someone hauled the habitat off somewhere and we've never found it again. Hate that when it happens.