spotting tuna

[Sallysea]

Hello,
I currently have a c127 with a 50/200, 600kw transducer and an a78 with downvision.

I fish for albacore that are suspended in deep water. The bottom is a couple thousand feet down. Currently, I set the units to manual at 150 feet full screen. Have tried all three frequencies with some success. Among the products you sell, is there a better transducer or unit available for this type of fishing. Our troll speed is 6-8kts.
Do you have any suggestions on improving the search?

It would be really neat if there was a way to see to the side when searching for fish, but all the side scans that I have owned don't work for this kind of fishing. They apparently work better in shallow water where they can find the bottom. Suggestions?

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Sallysea,

The bottom depth which you have specified exceeds the operational depths for both DownVision and CHIRP (high CHIRP conical) provided by the a78, as well as for the 600W 50 kHz / 200kHz fishfinder circuitry of the ax7/cx7/e7D/ex7/eSx7 MFDs. For operation in depth specified, it would be recommended that a CP470 or CP570 high power CHIRP sounder module with wide beam LH-W CHIRP transducer a be added to this system if seeking fish at depths to the bottom. Should I have misunderstood your query and should you be seeking recommendations for finding fish suspended within the upper 150' when operating in the depth specified, then please respond accordingly.

[Sallysea]

My fault in not making myself clear. The intent is to locate tuna in the top 150' of the water column and ignoring the other 1850'.
what would be optimum is as wide a cone angle as possible with adequate gain to get a good signal return. I know 50khz is wide and have used that. Just wondering about other options as the signal strength is not good at times. I am using a standard transom mount transducer.

[Chuck - Raymarine - Moderator]

Sallysea,

With respect to adjustments using the currently installed equipment, I can only recommend that you try to use to the Zoom feature only show the top 150' or so of the water column and that you try increasing the Gain settings to better show fish targets. With respect to equipment additions, the aforementioned CP470 CHIRP Sounder Module with a A80318 TM275 LH-W - Transom Mounted Wide CHIRP Sonar Transducer may be just what you are seeking to improve marking fish within the upper 150' of the water column.

[Sallysea]

looks like I will live with what I have. The cost of the cp470 and the transducer is a little steep. Will try setting up a FF icon with dual screens, one of them zoom .

[Chuck - Raymarine - Moderator]

You're welcome.