Transducer leveling issue?

ChaseTheBait

Eat em raw
Mar 19, 2019
83
102
35
San Diego
Name
Chase
Boat
Carolina Skiff 1800
I recently installed the Lowrance Hook2 7 on my CC, and am having some minor issues as expected. The transducer is a triple shot so it is like 12" long.

The only issue I have is that in deep water (maybe over 60ft) the bottom just looks flat and nothing is picked up pretty much anywhere in the water column. Just blank space. In mission bay I can see everything pretty well, mark fish, see grass, etc., and in the kelp it picks up kelp stringers, fish, seals, etc. But when I go out to 100-200ft deep it looks completely empty and the bottom only shows slight variations.

Temps, speeds, and depths seem to be correct, and everything seems to work well at cruising speed. I'm assuming that since it works shallow it must be a leveling issue (the deeper I go the worse the return signal)? I leveled the transducer the best I could by running a straight edge along the bottom of the boat, but the transducer is so long that is it level in the front, but as it moves away from the boat it lifts slightly until it is maybe 3/4" too high at the back.

I'm just wondering if I should bring a level on the water and check the boat while it is not moving on the water, and level the transducer to that, or if I should idle at 4-5mph and level to that plane? I've never had to mess with such a long transducer before. It's mounted on a stern saver so I can move it around a bit as needed.
 
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mullet

Metal Fabricator
Jan 10, 2006
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Brookings Oregon
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mike
Boat
19"Gregor
Have you tried zooming in deeper water ? The deeper you are the variations are going to look smaller due to more target on the screen .
 
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ChaseTheBait

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Mar 19, 2019
83
102
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San Diego
Name
Chase
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Carolina Skiff 1800
Have you tried zooming in deeper water ? The deeper you are the variations are going to look smaller due to more target on the screen .

I'll try to zoom in on the bottom to see if it looks different. But something definitely looks off if at 100ft im getting stuck in rocks and catching fish and everything looks clear and the bottom looks really flat. I should be able to see some kind of rock piles or something.
 
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CMOR_Mapping

CMOR Mapping
Sep 10, 2020
7
3
Florida, USA
www.cmormapping.com
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CMOR Mapping
Boat
Survey Vessel
Could possibly be the transducer strength and frequencies that it works on. Typically deeper water you are going to need a stronger signal and lower frequencies. However you should be able to get a little something out of that transducer in those depths.

Have you checked settings to see if you can tune up the gain any. I am not super familiar with the settings on the Hook units. If you can increase the gain you should be able to pick up more targets in the deeper depths and get some bottom structure to show.

As stated above zooming in on the bottom if you are strictly looking for bottom structure will help as well.
 
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ChaseTheBait

Eat em raw
Mar 19, 2019
83
102
35
San Diego
Name
Chase
Boat
Carolina Skiff 1800
Could possibly be the transducer strength and frequencies that it works on. Typically deeper water you are going to need a stronger signal and lower frequencies. However you should be able to get a little something out of that transducer in those depths.

Have you checked settings to see if you can tune up the gain any. I am not super familiar with the settings on the Hook units. If you can increase the gain you should be able to pick up more targets in the deeper depths and get some bottom structure to show.

As stated above zooming in on the bottom if you are strictly looking for bottom structure will help as well.

I've increased the sensitivity and it just shows all kinds of noise all over the entire screen. So I just increase it by 2 to try to pick something up. Can pick up things 20-30ft under the boat great like sealions or kelp.
 
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ChaseTheBait

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Mar 19, 2019
83
102
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Chase
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Carolina Skiff 1800
What frequency is the transducer

High CHIRP, wide angle operates at 200 kHz, while SideScan and DownScan Imaging operate at 455/800 kHz.

I honestly haven't messed with the side and downscan very much but it seems to be about the same, showing nothing much in the water column.
 
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Unassailable

Professional Amateur
Aug 26, 2009
1,327
729
San Diego
Name
John B
Boat
BW
I agree with what everyone has said before. That 200 kHZ regular sonar only uses 200 watts. While that should be enough wattage at that depth (not great though), high frequency push needs more power. That transducer is really more of a low end freshwater/bay/inshore transducer IMO. Zooming in may help.

You really want a higher wattage transducer with a lower frequency to penetrate saltwater and all the sediment it has in the water column if you want bottom detail. A 600 watt 50 kHZ transducer will be more than ample for up to 300ft of bottom detail and should track bottom to about 1000 ft.

Also, I think your inclination is correct about the level. If you were to err on the side of higher or lower on the backside of the transducer, you'd want to make sure it is a little lower (pointing forward) so the cone has time to shoot back at you as you are cruising. You may never be getting a return as the cone is expanding farther away from the boat the deeper you go.

I went through a few different transducers trying to figure this out years ago, so this is just what I've experienced.
 
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ChaseTheBait

Eat em raw
Mar 19, 2019
83
102
35
San Diego
Name
Chase
Boat
Carolina Skiff 1800
I agree with what everyone has said before. That 200 kHZ regular sonar only uses 200 watts. While that should be enough wattage at that depth (not great though), high frequency push needs more power. That transducer is really more of a low end freshwater/bay/inshore transducer IMO. Zooming in may help.

You really want a higher wattage transducer with a lower frequency to penetrate saltwater and all the sediment it has in the water column if you want bottom detail. A 600 watt 50 kHZ transducer will be more than ample for up to 300ft of bottom detail and should track bottom to about 1000 ft.

Also, I think your inclination is correct about the level. If you were to err on the side of higher or lower on the backside of the transducer, you'd want to make sure it is a little lower (pointing forward) so the cone has time to shoot back at you as you are cruising. You may never be getting a return as the cone is expanding farther away from the boat the deeper you go.

I went through a few different transducers trying to figure this out years ago, so this is just what I've experienced.

Thanks for all the good info. This is what I'll be working with for now so I guess it'll have to do. Hopefully I should still be able to ping fish that are closer to the boat in the water column.
 
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ShadowX

I Should Upgrade My Account
Oct 10, 2010
2,348
2,585
Los Angeles
Name
Alex
Boat
None
Its your transducer angle that needs to be adjusted properly. The 200w should allow you to go down to 500 feet if you are not moving. There are three adjustments you need to make.

The first one is the angle in relation to the center line of the boat. If the transducer is cocked to one side, the beam does not reflect back to the boat at deeper water. The way you can tell your angle is off is to drive the boat and put it on plane. If you don't see the bottom being tracked while you are moving, turn left or turn right. If you suddenly see the bottom, it means your transducer is tilted to that side slightly. One trick I use is get an app for the phone that you can measure angle like a level bubble. Use that on top of your transom to get a baseline measurement. When you mount the transducer, put the phone on top so its flat and make sure the angle matches the reference from the top of the transom. It would mean you are close to parallel to the transom and pointing straight down perpendicular to the center line of the boat. Once you are sure its perfectly lined up to the centerline, draw a line parallel to the mounting bracket with a sharpie. This line tells you the angle you want to maintain when you make other adjustments.

The second adjustment is the position of the transducer in height away from the water column on the bottom of the boat. It is much easier if you have a transducer mounting plate. It allows you to drill new mounting holes without having to worry about leaking into the transom. You basically move the transducer up and down to have the correct distance in relationship to the water flow. Use the line you drew before as a reference to make sure your transducer is lined up properly. Your mounting bracket should always be parallel to the line as you make these other adjustments. Most mounting suggest the location to be a half way point of the deadrise angle. I would say experiment because every boat is slightly different. You may get better performance moving it down further or it might actually get worse. The main thing to watch out for is to ensure there is no obstruction in front of where you mount your transducer that can cause turbulent water flow. If you have a strake or pump intake screen in front of the transducer, that is not a good location for the transducer..

The third adjustment you need to make is the angle of the transducer to the water column. Generally, you want the end to be further down so it bites into the water as it flow by. However, too much is not good either. You will create a rooster tail and you will also create more turbulence around the transducer.

I have adjusted some transducers 10-20 times until it worked perfectly. You just need to experiment and each boat is different. The first thing to make sure you can track bottom when the boat is stationary. After that, you make adjustments so it can track while you are moving at planing speeds. That second part is harder on a transom mounted transducer. The good part is the 200 KHz frequency has better noise rejection for air bubbles. At 50 KHz or 83 KHz, it is more sensitive to bubbles.

With a 3-in-1 transducer, it will never be perfect. The position/angle for best performance in plane may not be the best angle when you are doing side scanning. When you use side scan sonar, the boat is moving slower and the bow of the boat is higher. The transducer works slightly better when the back is angled up. It keeps the transducer parallel to the water column at the slow speed. However, the up angle is not good for high speed tracking since its better when the transducer is tilted down. Its all a compromise based on what sonar functions you use the most. Ideally, if you want the best performance, get an Airmar transducer. They have higher sensitivity and sharper response curve (or "Q").
 
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ChaseTheBait

Eat em raw
Mar 19, 2019
83
102
35
San Diego
Name
Chase
Boat
Carolina Skiff 1800
Its your transducer angle that needs to be adjusted properly. The 200w should allow you to go down to 500 feet if you are not moving. There are three adjustments you need to make.

Thanks for the input. I'm going to go through this checklist within the next few days. This makes me feel better about using what I have, I just need to adjust until I dial it in properly. Luckily it is mounted to a stern saver.
 
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