How accurate are ALL depthfinders?

[walleyehed]

Re: How accurate are ALL depthfinders?

ThomWV, great explanation....taught me something, Thanks!

 

[18rabbit]

Re: How accurate are ALL depthfinders?

Something just dawned on me… sound travels faster thru denser material. My books are packed away so I can’t reference them but if my memory is correct (no guarantees or warranty implied ) sound travels at something like 1120-ft/sec in air, and somewhere close to 8 or 12 times faster (can’t remember) in sea water…either 8960-ft/sec or 13,440-ft/sec. That’s why you cannot tell the direction of travel for a boat motor when you are underwater…you can hear it very clearly but your ears aren’t far enough apart to get a bearing on the origin of the sound traveling at that speed.<br /><br />Where does the measure of 4500-ft/sec for the speed of sound in water come from?

 

[ThomWV]

Re: How accurate are ALL depthfinders?

18Rabbit,<br /><br />Every reference I've run across tells me 4,500 ft/sec.<br /><br />Thom

 

[18rabbit]

Re: How accurate are ALL depthfinders?

Got it. The velocity of sound is:<br /><br />343 m (1127 ft) per second in air at 20C (68F)<br />367 m (1137 ft) per second in air at 25C (77F)<br /><br />1482 m (4862 ft) per second in fresh water at 20C (68F)<br />1493 m (4898 ft) per second in fresh water at 25C (77F)<br /><br />1533 m (5030 ft) per second in sea water at 25C (77F)<br /><br />I would presume the magic number of 4500-ft/sec is an acceptable working average for the velocity of sound thru fresh and seawater, warm and cold.