[TG] [TG11] Marking Fish in Deeper water

[solidnetworks]

Hi,

i have an Axiom 9 with the RV-100.

it is marking fish in shallow water up to about 30 meters deep.

i have been out a few times between 90 and 130 meters and it shows the depth fine, it doesn't seem to be marking fish though screen is completely blue and only shows the bottom. i thought its just that there wasnt many fish in the sea the first couple of times :) even though others where catching fish near us..

i went out last weekend offshore to a Fish Attracting device and we where able to see the fish jumping out of the water and heaps under the boat, the depth was about 130 meters and it still was not showing anything on the sonar, i tried to adjust the settings from the default AUTO setting and couldn't work out what to set them at and which one to adjust.


From all the searching i have been doing on this forum for the last few months, the Axiom 9 with the RV-100 should mark fish up to about 300 meters?

i have the latest software installed.

[Tom - Raymarine - Moderator]

Hello Solidnetworks,

I wouldn't say that the RV system could mark fish in 300m - I'd say that that was about the upper limit for marking the bottom, but it's unlikely to show anything much smaller than a large, dense bait school deeper than 150m or so. Generally I recommend RV for use in up to around 100m of water. People do certainly use it deeper with good results, but that's dependent on water conditions, the noise environment of the boat (electrical background noise, hull vibration etc.) and the user's expectations so I prefer to err on the side of caution.

I would definitely stay on Auto for all of the Sensitivity settings - only the most experienced charter skippers, on the water 200+ days a year can generally out-perform Auto - but I would use Auto+50% Gain when in deep water, and offset this with an Auto-minus (say Auto-20%) Contrast/Intensity/Colour Gain so that the image isn't too over-saturated and simply red/blue (if it is, you lose valuable information about the strength of the return which can help separate a school of bait from a single predator.)
One exception to the all-Auto rule is if you're looking for surface fish, e.g Mahi mahi around the FAD. In that case it would be a good idea to use 0% Surface Filter/Noise Filter (TVG), because non-zero Surface Filter can reduce the intensity of near-surface echoes.

If you'd like to take some photos or better, screenshots (via the Power menu) next time you're out, I may be able to say more. If taking photos, please make they're high-resolution, in-focus and include the whole screen rather than just a part.

Regards,
Tom

[solidnetworks]

Hi Tom

Thank you for the reply,

i will try the settings as suggested, and take some photos of the screens i get.

what will i need to upgrade to be able to get a better reading in deep water? i plan to start venturing out to 500- 1000 meters.

Thanks
George

[Tom - Raymarine - Moderator]

Hi George,

This question which I've just answered posted a very similar question, worth having a look. For bottom-tracking in 500-1000m I'd say CP370 with 1kW transducer as a minimum, CP470 with 1kW as the recommended system.

If you want to track the bottom whilst also looking for pelagics (running two very different range scales at once) then you really need CP570 rather than CP470. One example of this is people fishing for marlin in Seal Rocks canyons, NSW. A CP470 will track the bottom in over 1000m at trolling speeds, but if you also try to look at the near-surface layers split-screen, dual-range, then the CP470 has to alternate pings between the shallow and deep ranges and you end up with an unusably slow ping-rate for the shallow range. The CP570 has dual independent transceivers and can ping two different ping rates on the two ranges, fast/shallow and slow/deep.

As I mentioned to the other poster, there are a lot of different transducer options for different mounting styles and fishing types, so you should go through that with us or your dealer before making a decision about a specific transducer. There's no one-size-fits-all.

Regards,
Tom

[solidnetworks]

Hi Tom,

Thank you for the information, i have been monitoring the other threads on this also and seen the options for the better transducer and cp470.

i have also watched the youtube video for the cp570 looks good, a bit out of my price range for the time being and my Tinnie is much smaller than that :)


i guess i will look into it once i get more experience and start venturing out chasing Marlin etc.

for the time being as long as i can get it to work in up to 150m finding fish that will do the job.


i am planning on getting out to the fads off Sydney tomorrow so i will test it out and get you some photos.

[solidnetworks]

Hi Tom,

i went out again this weekend to the botany wide FAD and was not really sure about it, it could be just that i am not reading it correctly.

in 100m water i guess fish will just show up as dots? we drifted around out there and didnt really mark anything, didnt really get much bites either so it could just be that there wasnt much there.

i am guessing that single fish like kingfish would be a faint dot when looking at the screen as a whole, then need to zoom in to make it look larger?

a school of yellowfin and mahi and who knows what else turned up but we where too frantic trying to catch them to look at the screen.. i am guessing that i would have had to have the surface filter set to zero as you suggested for them to show up as they where feeding on the surface?

[Tom - Raymarine - Moderator]

Hi George,

Sorry for the delay replying.

Next time you're out, take some screenshots and send them in to us here so that we can see what you're seeing. We'll be able to give you better advice that way.

Regards,
Tom