[DG] [TG11] RV100 Axion 9 loosing bottom at speed

[fish for fun]

I have just fitted the axiom 9 with real vision into my boat
I set the transducer up as per instructions taking care to check the lines in my hull to stop any bubble lines forming under transducer
single engine 90 HP Murcury
Rv 100 Transducer mounted on RH side
hull is a whittley sea legend 5
The boat is only a 5 mtr boat but i have had 2 problem while setting it up

1 I loose the bottom if I am traveling at speed. If I am on the plane at low speed reads ok. At high speed it looses bottom
2 if I lower the transducer future into the water the transducer acts like a trim tab and pushers the side of the boat up and now has become very uncomfortable to ride in the boat

Any help would be appreciated to work through the problem

[Tom - Raymarine - Moderator]

Hello fish for fun,

Yes, we can work out what's going on there. The problem may well not be aeration, which is why changes of transducer position haven't fixed it - it may well be a noise problem instead.

I'd have a look at this FAQ first of all: http://forum.raymarine.com/showthread.php?tid=9371
I would also suggest having a look at this post which I am also working on which shows exactly the sort of tests we need to do to find out what's going on. This owner's transducer is definitely not suffering aeration: he has a noise problem.

Please do the same 65/15/0 tests and post pictures back here for me to have a look at.

Thanks,
Tom

[fish for fun]

Hi TOM
Tom - Raymarine - Moderator' pid='38845' dateline='1583736085
Thanks for the quick response
I have printed out the tests you have ask me to perform and plan to do this on the weekend 14/3/2020
I have also printed out the other thread 10464 and read it
I have taken a couple of photo's of the back of boat and excess cable near fuse panel
I have a duel battery set up, one battery for all the electronics's and the other for engine this did not effect sounder at all on any combination with the battery's

[Tom - Raymarine - Moderator]

Hi fish for fun,

Dual-battery systems are good from the points of view of not accidentally draining your start battery with your electronics, and not having the electronics restart when you crank the engine, but you don't necessarily have isolation between those batteries so it doesn't necessarily prove that you don't have a power supply interference problem. The negatives are almost certainly bonded for example, and you may well be charging House through a VSR or similar.

Regards,
Tom

[fish for fun]

HI Tom
Sorry for the delay with the discussion ( Covin-19) in Australia and we have been locked down and not been able to get onto the water till now

So after looking at other treads and and discussions on the forum I decided to pull side of the boat apart and look where the cable had been run and decided that laying next to all the other cables did not work for me and I re-wired half my boat and ran all the power cables in a electrical ducting along the boat and the transducer cable in a second ducting 150 mm away from the other cables. Put the boat back together and took it out on the water and it has improved all my screens and sounding's about 70/80 % but still having trouble that traveling at speed it reads for about 2 mins then stops reading and the bottom is lost .

trying to work out how to get screen shot onto post for you.
do i sent pic's as tumbnail size or bigger

[fish for fun]

Hi Tom
photo's of my testing
Hope I have completed tests correctly

[Tom - Raymarine - Moderator]

Hello fish for fun,

Your system is working very well, for those speeds. The RV-3D will never work at high speed, that's normal and expected (it's not designed to, and can't do that level of signal processing on the messy, noisy signals that you inevitably get at high speeds), but your SV and Sonar channels are working very well considering the speed (personally I have never seen SV look as good as in your 50.4kph shot, at that kind of speed.)

You do have some pulsed noise in your Sonar channel that's very apparent in the 50.4kph shot (the vertical stripes/columns of much higher background clutter) and by carefully watching that screen whilst feeling/listening what's happening with the boat at the time you might be able to narrow down where that noise is coming from (for example, is it when the boat ploughs into the back of a wave) and maybe get the image even better. You can also improve the high-speed bottom-tracking by using an appropriate manual range setting, but if you consider that the transducer is a sensitive microphone and how much actual noise there is for it to pick up, in a 50kph water flow, mounted on a vibrating transom and close to a noisy outboard and prop, it's not at all surprising that it's giving a cluttered image. How much wind noise would your phone microphone pick up if you tried to make a call in the wind at that speed?

You definitely don't have a problem with your transducer height/angle from the point of view of aeration, and you definitely don't have a fault with your system, and if you can find where that pulsed noise is coming from you might be able to improve your high-speed performance from good to outstanding.

By the way, because of the angle of the view I can't see whether the RV image is normal at low speed, but I assume it would be based on the other images.

Regards,
Tom

[fish for fun]

HI Tom
I have sent you another photo of what I did with the power cables with my boat and how I ran extra cable up to sounder to reduce the noise from the boat /power cables .
Power cables running into top conduit
Two lower conduit is the Transducer cable and to hold extra cable
This has worked very well for me as you can see from the transducer pic's

The main problem I had was loosing all soundings of the bottom at around 20kph
and had no picture just a line with no depth or bottom
Hope this helps other people fix some of the noise problems when running the transducer cable

I wish to thank you for you time TOM ,and Raymarine customer service
Happy customer
Fish for fun

(04-01-20 01:46 AM)Tom - Raymarine - Moderator Wrote:  Hello fish for fun,

Your system is working very well, for those speeds. The RV-3D will never work at high speed, that's normal and expected (it's not designed to, and can't do that level of signal processing on the messy, noisy signals that you inevitably get at high speeds), but your SV and Sonar channels are working very well considering the speed (personally I have never seen SV look as good as in your 50.4kph shot, at that kind of speed.)

You do have some pulsed noise in your Sonar channel that's very apparent in the 50.4kph shot (the vertical stripes/columns of much higher background clutter) and by carefully watching that screen whilst feeling/listening what's happening with the boat at the time you might be able to narrow down where that noise is coming from (for example, is it when the boat ploughs into the back of a wave) and maybe get the image even better. You can also improve the high-speed bottom-tracking by using an appropriate manual range setting, but if you consider that the transducer is a sensitive microphone and how much actual noise there is for it to pick up, in a 50kph water flow, mounted on a vibrating transom and close to a noisy outboard and prop, it's not at all surprising that it's giving a cluttered image. How much wind noise would your phone microphone pick up if you tried to make a call in the wind at that speed?

You definitely don't have a problem with your transducer height/angle from the point of view of aeration, and you definitely don't have a fault with your system, and if you can find where that pulsed noise is coming from you might be able to improve your high-speed performance from good to outstanding.

By the way, because of the angle of the view I can't see whether the RV image is normal at low speed, but I assume it would be based on the other images.

Regards,
Tom

[Tom - Raymarine - Moderator]

Thanks very much for the feedback, Fish for fun, that's great that you got that much of an improvement from re-routing the cabling. I hope this info is of use to other users, I really appreciate you posting back here to let us know.

Happy fishing, when next you're allowed back on the water.

Regards,
Tom