Prop Exhaust

[cache22]

I was wondering if the effects of prop wash as shown in humviewer are real..... if so, one should be cautious about motoring, even at slow speed, over your favorite honey hole! These shots indicate effects clear to bottom in 37' of water or is it just the way the data has been rendered??

[jaxsprat]

my prop wash is just mixed air and water and always rises to the top of water surface

[Redge]

I have seen something very similar and it goes deep as you stated!

[rnvinc]

Could be plankton ...

Rickie

[cache22]

Always thought it was exhaust gasses mixed into the prop turbulence. Never would have guessed it reached this deep.

[CrappiePappy]

Always thought it was exhaust gasses mixed into the prop turbulence. Never would have guessed it reached this deep.

It wouldn't unless you had your boat practically standing on end.
Prop turbulence won't go more than a few feet deep, if that, since the gasses would rise quickly once the water current from the prop had dissipated some.

... cp

[kickingback]

I get that image now and then when I start out with my motor on full. I myself assumed it was from the prop wash and wondered the same thing, why it looks like it goes down so far. But after reading about the "cones" of the sonar I came to the conclussion that the prop wash is sent out in all directions out the back and the sonar picks up on air bubbles and with the air bubbles in the cone of the side imaging it shows them like they go all the way down. If you notice the wash in the image as you drive away the image of the wash slowly dissipates and goes away when the bubbles have risen out of cone.

[genec]

DISTANT AWAY,DOES NOT HAVE TO BE THAT DEEP, JUST THAT FAR AWAY,CAN BE ONLY A FOOT DEEP BUT 20 FEET AWAY AND WOULD LOOK LIKE THAT DEEP,THAT IS WHY A BRUSH PILE MAYLOOK LIKE IT IS 15 FEET TO TOP BUT TO ONE SIDE BUT IF U GO STRAIGHT OVER IT THEN IT IS 5 FEET TO TOP,EVEN ON DI AND 2D U MUST GET STRAIGHT OVER IT TO TELL HOW CLOSE IT IS TO THE TOP. THAT IS WHY WE SOMETIMES HANG UP WHEN WE COUNT DOWN OUR JIG WHEN WE THOUGHT THE PILE WAS DEEPER,WE WERE NOT STRAIGHT OVER IT ,HOPE THIS DO NOT CONFUSE U,ON DI WHEN I GO OVER PILE I LOOK AT BOTTOM AND SEE IF BRUSH LOOK LIKE IT IS DEEPER THAN BOTTOM APPEAR AND IF SO HOW FAR IT LOOKS TO GO PASS BOTTOM AND ADD ABOUT THAT MUCH MORE TO TOP OF BRUSH

[cache22]

DISTANT AWAY,DOES NOT HAVE TO BE THAT DEEP, JUST THAT FAR AWAY,CAN BE ONLY A FOOT DEEP BUT 20 FEET AWAY AND WOULD LOOK LIKE THAT DEEP,THAT IS WHY A BRUSH PILE MAYLOOK LIKE IT IS 15 FEET TO TOP BUT TO ONE SIDE BUT IF U GO STRAIGHT OVER IT THEN IT IS 5 FEET TO TOP,EVEN ON DI AND 2D U MUST GET STRAIGHT OVER IT TO TELL HOW CLOSE IT IS TO THE TOP. THAT IS WHY WE SOMETIMES HANG UP WHEN WE COUNT DOWN OUR JIG WHEN WE THOUGHT THE PILE WAS DEEPER,WE WERE NOT STRAIGHT OVER IT ,HOPE THIS DO NOT CONFUSE U,ON DI WHEN I GO OVER PILE I LOOK AT BOTTOM AND SEE IF BRUSH LOOK LIKE IT IS DEEPER THAN BOTTOM APPEAR AND IF SO HOW FAR IT LOOKS TO GO PASS BOTTOM AND ADD ABOUT THAT MUCH MORE TO TOP OF BRUSH

I think this is right, Genec! It is the way down image is generated from the side image on my 998. Clue is in the wash track I went over at an angle showing 2 legs compared to the one I crossed at 90 degrees having only 1 leg. Guess I will stop worrying about stirring up my honey holes and forget using down imaging. (it sux)

[slabbacks]

Yea cache, your good to go. That prop wash is at the top but just misleading the way BH DI is having to use the SI. What caught my eye was that standing timber, may be a sweet spot this winter if that's your max depth.