Sonar wattage for offshore fishing?

[Tyangelo]

This long-planned offshore fishing trip for salmon, prawns etc,?is coming up, and other than mounting the kicker, everything is good to go. Am, however curious as to how I can expect my current sonar to perform in 200'+ water.

Right now, running an Eagle Fisheasy 320C. 60 deg beam, and 800 w, (100 rms). Transom mount. What can I expect from this unit? Would I really benefit that much from looking at installing a more powerful etc unit, or should I be fine with the 320C?

[TJG]

If you want your sounder to be able to shed some light on the composition of the bottom under your boat or use it for fish finding in water over a couple hundred feet deep you’ll be best served by choosing a unit with dual frequency capabilities and at least 500 watts RMS power output.

Most recreation depth sounders have between 100 and 1000 watts of RMS power. The definition of RMS power is really irrelevant; we just need to compare units on an even keel. So remember, if a unit states maximum power with a peak-to-peak rating that is simply eight times its RMS power rating. So a machine rated at 4800 watts peak-to-peak is also rated at 600 watts RMS.

The maximum depth capability of a fish finder with 500 watts of output power would be about 500 feet at 200 kHz and somewhere between 1000 and 2000 feet using 50 kHz.

Originally Posted by Tyangelo

This long-planned offshore fishing trip for salmon, prawns etc,?is coming up, and other than mounting the kicker, everything is good to go. Am, however curious as to how I can expect my current sonar to perform in 200'+ water.

Right now, running an Eagle Fisheasy 320C. 60 deg beam, and 800 w, (100 rms). Transom mount. What can I expect from this unit? Would I really benefit that much from looking at installing a more powerful etc unit, or should I be fine with the 320C?

[Kokanee9]

May I suggest trying a BC fishing forum. http://www.bcfishingreports.com/forums/forum.php

My boat has never touched salt water and I don't see too many answers pouring in here. I'm thinking a lot of other people on here have not tried that particular model in salt water.

Manufacturers website as a source of help perhaps?

[incept]

To be honest, your current unit will not provide the results you are after. For serious fishing in the salt you'll need to step up the game in sonar quite a bit. It may work ok however you will miss most of what you are after. For really good results, check out the Furuno and Raymarine stuff. The upper end 'bird and Lowrance also work well. Pick up a 1kw transducer for it and your good to go! Have fun!

[elnino54]

I haven't tried anything else, but the Furuno unit on my boat is 600 watts and it works fine.