Transducer Mounting - No Spray at Speed?

[Bigstorm]

I put a new locator on the boat this spring and have had problems getting it positioned correct so that it wouldn't spray up and get water in/on the back of boat at speed and also to have it read depth at speed. (when I say ready depth at speed I mean 20 to 30 mph, boat tops out at 31mph)

I believe the problem was that it was mounted too low in the water when I first installed it. I had to replace the mounting board to raise it up and now have it positioned so that is sits just barely below the bottom of the boat.

My hope is that it doesnt spray water up on the back of the boat and also reads depth properly at speed. Take a look at the 2 pictures and tell me if you think I'm in the ballpark now or if it would need to be mounted higher yet

Thanks

[nikmark]

Looks to me like the transducer mounting board is extending below the bottom of the transom and causing the spray.

[Bigstorm]

the board is sitting flush with rivets on the underside of the boat. The old mounting board was in the same place and it didnt spray until I installed the new locator/transducer.

I mounted the new board in the same location (as close to as possible so I could avoid drilling new holes in the boat

[nikmark]

Okay, must just be the way the photo looks. You might try adjusting it up a little more and tilting the back edge of the transducer down. Water might be catching on the front edge causing it to shoot up. It looks really level in your photo, but the way your boat sits when running may make the front edge lower than the back edge.

[REW]

There is a very simple solution.
1. Forget about the spray.
2. Adjust the transducer however you have to adjust it to get a perfect reading at all speeds from stopped to going wide open.
3. Now, if you have spray from the transducer, make a spray hood and screw it to the transducer board.

If you find that you are getting objectionable spray when going at speed, have someone else drive, the boat and with you wearing a life jacket - peer over the boat - and determine the pattern of the spray. Determine what and how much have to be covered with a spray shield.

Generally, when making such a spray shield, it does not have to be very big. You just need something to keep any spray that might be going vertical to not get to any place in the boat. A simple piece of aluminum as wide as is needed with a flange bent into one side and screwed into the transom will solve the issue.

Bottom line - you really don't care about spray, but you do care about a good transducer readings at all speeds.

When you go to do some testing, you could bring along a foot long piece of 1X4 or 1X6 and hold it in the general area of the transducer to see if one or the other would be sufficient to eliminate the problem before actually bending up a piece of metal and mounting it on the boat.

You might actually find that a deflector that is angled up at 45 degrees or so might be perfect. In other words, just deflect any spray that might come up - back far enough so that it never comes into the boat. Just deflecting the spray is likely a better solution than trying to blank it out entirely.


p.s.
You are not alone. I have seen quite a few boats which have a considerable transducer caused spray that gets the rear of the boat wet, especially during certain wind conditions.

REW

[MC620]

Even simpler solution:

cover the gap in the bracket mounted to the boat with a couple wraps of tape.

sheesh.........

[fireboat]

Originally Posted by Bigstorm

I put a new locator on the boat this spring and have had problems getting it positioned correct so that it wouldn't spray up and get water in/on the back of boat at speed and also to have it read depth at speed. (when I say ready depth at speed I mean 20 to 30 mph, boat tops out at 31mph)

I believe the problem was that it was mounted too low in the water when I first installed it. I had to replace the mounting board to raise it up and now have it positioned so that is sits just barely below the bottom of the boat.

My hope is that it doesnt spray water up on the back of the boat and also reads depth properly at speed. Take a look at the 2 pictures and tell me if you think I'm in the ballpark now or if it would need to be mounted higher yet

Thanks

If you put a straight edge from the boat to the mounting board you will see how much the mounting board is below the bottom of the boat. The board has square edges, the back of the boat is at an angle. Sand or file the trailing edge of the board to be inline with the boat. This may not be the spray problem but with the edge of the board below the boat it's creating unnecessary drag.

[DJL66]

This may not be the spray problem but with the edge of the board below the boat it's creating unnecessary drag.

I thought the same thing when I had looked at your pictures. When I had installed my transducer board I took in consideration the angle of the transome and bottom of the boat with the boat sitting level. I believe there was about 7 degrees difference and cut the bottom edge of the board to match the boat bottom and placed the board slightly above the bottom edge. If the board is below the boat it causes extra turbulance and gives poor readings. I get a clear reading at 40+ mph with mine. Took a little fussing around but works great.
BTW with the way I have mine set up I get no spray from my transducer.

[SpokaneJim]

I agree with the last two replies regarding the transducer mounting board. My boat had a 14 degree angle from the bottom of the boat. I cut the bottom of the board to match this angle. In addition, everything I read about mounting it said to set it up from the bottom of the boat by 1/4". Then you'll have a free and smooth flow of water from the bottom of the boat to the transducer (assuming of course there are not any rivets, etc. on the bottom of the boat that may cause turbulence.) Again, probably has nothing to do with a spray problem, but would have an affect on quality of signal at high speed.