Getting Transducer Parrallel

[isljam]

Hey folks.

Ok, maybe a dumb question, but how do you level the transducer horizontally, i.e. starboard to port (not vertically, I get how to do that) so it is perfectly parallel with the bottom. Obviously, I’m doing the install on dry land with boat on trailer.

I know the driveway is not level. And even it was, I can’t assume the boat is perfectly level sitting on the trailer.

I decide to use a spirit and wheel jack to get the boat level. But what surfaces can I assume are level on the boat.

Not sure the transom is level or the carpeted floor. Do I just lay a spirit level from starboard beam to port and assume that is a level surface?

Man It seems whenever I undertake a DIY, seemingly simple steps become overwhelmingly complicated. But I’m determined to get this done.

 

[dingbat]

Hey folks.

Ok, maybe a dumb question, but how do you level the transducer horizontally, i.e. starboard to port (not vertically, I get how to do that) so it is perfectly parallel with the bottom. Obviously, I’m doing the install on dry land with boat on trailer.

Eye ball…..

As you noted, the exercise is to mount the transducer parallel to the bottom (of the water), not the boat. The only way to do it otherwise is to float the boat and go from there.

Having said that, you will find the transducer’s fore and aft adjustment to be far more critical to performance.

The ability to run WOT without interfere is the ultimate goal. Some hull configurations/designs will not run a clean transom mount no matter what you do.

 

[isljam]

Eye ball…..

As you noted, the exercise is to mount the transducer parallel to the bottom (of the water), not the boat. The only way to do it otherwise is to float the boat and go from there.

Having said that, you will find the transducer’s fore and aft adjustment to be far more critical to performance.

The ability to run WOT without interfere is the ultimate goal. Some hull configurations/designs will not run a clean transom mount no matter what you do.

Re clear water. That is another concern as the chines are quite close together. There is just enough width in between to cover the width of the transducer.

There is a wider gap but that is right at the widest point of the boat. Not sure if that is ideal, as most instructions suggest midway between motor and edge of bow.

 

[robert graham]

I don’t think the transducer has to be perfectly parallel with the bottom…just eyeball it when you get in the water….mine is mounted on a little up/ down pivot with a nut/ bolt friction deal to prevent it getting broken off upon an impact with solid object….if it gets knocked up or down say 5 degrees or so then the depth reading will be off…I just reach down and set it about level with the water surface….it’s not a big deal…

 

[isljam]

I don’t think the transducer has to be perfectly parallel with the bottom…just eyeball it when you get in the water….mine is mounted on a little up/ down pivot with a nut/ bolt friction deal to prevent it getting broken off upon an impact with solid object….if it gets knocked up or down say 5 degrees or so then the depth reading will be off…I just reach down and set it about level with the water surface….it’s not a big deal…

Right. I have a sliding transducer mount too. Small adjustments to fore and aft angle are easy. But left to right (horizontal level) are relatively fixed. So pays to get it as close as possible. Its the horizontal level I'm struggling with.

 

[isljam]

Right. I have a sliding transducer mount too. Small adjustments to fore and aft angle are easy. But left to right (horizontal level) are relatively fixed. So pays to get it as close as possible. Its the horizontal level I'm struggling with.

 

[dingbat]

Re clear water. That is another concern as the chines are quite close together. There is just enough width in between to cover the width of the transducer.

There is a wider gap but that is right at the widest point of the boat. Not sure if that is ideal, as most instructions suggest midway between motor and edge of bow.

Let’s start with what transducer are you installing and what are your expectations in performance.

If all you want is depth, it’s not complicated. It was done with weights and ropes for years. Bolt the transducer on the transom and go

If your goal is max. sensitivity and or installing side scanning, the margin of error becomes quite small both in location (distance from keel) and adjustment.

The deeper the water the more critical things become.

 

[isljam]

Let’s start with what transducer are you installing and what are your expectations in performance.

If all you want is depth, it’s not complicated. It was done with weights and ropes for years. Bolt the transducer on the transom and go

If your goal is max. sensitivity and or installing side scanning, the margin of error becomes quite small both in location (distance from keel) and adjustment.

The deeper the water the more critical things become.

Ok

The transducer is a Garmin GT56-UHD.

3-in-one td with side imaging, 2d and chirp down imaging to 1000hz.
Fishing mostly in 4-20m but up to 30-40m.

Just want the clearest image possible and ability to use different sonar functions. Generally sounding at trolling speed and no real facility for high speed readings. Though I know I can adjust for/aft angle of td to better match higher speed trim angle if needed.

 

[dingbat]

Ok

The transducer is a Garmin GT56-UHD.

3-in-one td with side imaging, 2d and chirp down imaging to 1000hz.
Fishing mostly in 4-20m but up to 30-40m.

Just want the clearest image possible and ability to use different sonar functions. Generally sounding at trolling speed and no real facility for high speed readings. Though I know I can adjust for/aft angle of td to better match higher speed trim angle if needed.

Same setup I’m helping a local board member install.

I’m running a GT51M with a separate CHIRP thru hull transducer for running. Way better high speed performance.

The location from the center line of the boat (15” from prop blades) isn’t negotiable. Otherwise you clip the outdrive with side scan.

The one thing they don’t address in the literature is sensitivity to heave. The higher the frequency the higher the resolution on the screen but it reduces the depth and increases sensitivity to heave considerably. I run 260kHz while trolling anywhere from 9 to 20 meter. Just turn it off on sloppy days

Interesting to see how that transducer performs at those depths in open water. 1000kHz isn’t doing you any favors.

 

[Bondo]

Ayuh,.... Just eyeball it,..... How often out on the water is a boat, dead level,..??
I'm guessin' next to never, with the wind, waves, 'n currents,.....

 

[isljam]

Same setup I’m helping a local board member install.

I’m running a GT51M with a separate thru hull transducer when running.

The location from the center line of the boat (15” from prop blades) isn’t negotiable. Otherwise you clip the outdrive with side scan.

The one thing they don’t address in the literature is sensitivity to heave. The lower the frequency the higher the resolution on the screen but it reduces the depth and increases sensitivity to heave considerably. I run 260kHz while trolling anywhere from 9 to 20 meter. Just turn it off on sloppy days

Interesting to see how that transducer performs at those depths in open water. 1000kHz isn’t doing you any favors.

Interesting. Thanks for the info re mounting position. I don't know much about the implications of heave. Will have to do some more research.

Why do you say the 1000hz is not helping? You said lower frequency = higher resolution but reduced depth? You mean higher frequencies right?

 

[dingbat]

Interesting. Thanks for the info re mounting position. I don't know much about the implications of heave.

In simple terms it the motion of the ocean. Up down, back and forth.

Just like the blur induced taking a picture of a moving object, the same blur happens to side scan when the boat is bouncing around.

In reality, I find side scan pretty useless on open water. Comes in handy though scanning bridge piling or grass beds on semi-claim days or on a boat big enough to remind stable under the conditions

You mean higher frequencies right?

Yes, I corrected it after the fact.

 

[isljam]

Interesting to see how that transducer performs at those depths in open water. 1000kHz isn’t doing you any favours. To clarify the frequency specs are:


Traditional High-wide CHIRP (150-240 kHz); ClearVü/SideVü 455 kHz (425-485 kHz), 800 kHz (790-850 kHz), 1000 kHz (940-1100)

Just curious why you say 1000kHz isn't doing me any favours?

 

[dingbat]

Just curious why you say 1000kHz isn't doing me any favours?

Couple of problems with that transducer..

The first is power. Unless they changed the specs of the head unit since I installed mine a couple of years ago, the unit is rated to run 600W conventional, 500W side scan.

The transducer you selected/came with the unit is rated at 350W. Your leaving a ton of power on the table in a game where putting power on the target is critical to performance.

Just as fyi, cut the advertised max. depth by half under real world conditions. This is with any unit, not just the one your installing

Issue 2…the higher the frequency the less penetrating power it has. Less power = less signal return = more gain = more distortion of image

This is a good primer on transducer performance though they don’t address side scan in particular. The same principals apply to side scan technology as well

https://www.airmar.com/uploads/brochures/guide-to-transducer-technology.pdf