What are your offshore fishfinders?

MattFred1414

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    For you guys in smaller private boats fishing bluefin, what fish finders are you using?

    I have an Axiom 9 which is great for nearshore, but it only reads depths to 900ft. Pretty much useless after that where the bluefin are sometimes.

    If I get the opportunity I’d like to catch a bluefin out of my rig with some flat falls. But I’d have to change up the fish finder setup. What’s your guys recommendation? I have a 20ft bay boat center console
     

    MattFred1414

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    Who's jigging for tuna at 900+ ft?
    I could be wrong, but anything over 900ft the signals won’t make it back to the transducer. So you won’t even see fish suspended 300ft down. I don’t have much experience trying to mark fish in >900ft of water and I thought that’s how it worked.
     
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    John Stidman
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    I just learned by reading on this site that if you set your depth manually and take it off auto it will not be searching for a bottom it can't read. In greater depths, set for your need.
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    Azores559

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    I could be wrong, but anything over 900ft the signals won’t make it back to the transducer. So you won’t even see fish suspended 300ft down. I don’t have much experience trying to mark fish in >900ft of water and I thought that’s how it worked.
    You don’t need to see bottom to get signal back from suspended fish.
     
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    OnoEric

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    I could be wrong, but anything over 900ft the signals won’t make it back to the transducer. So you won’t even see fish suspended 300ft down. I don’t have much experience trying to mark fish in >900ft of water and I thought that’s how it worked.
    When you’re offshore, set the depth scale manually to 300 feet or less. It doesn’t need a bottom lock to see fish in the top part of the water column. Auto-mode is not your friend offshore. Learn your fish finder settings so you can set at least the depth and gain manually.

    EDIT: I’ll give a plug to @Dave Hansen. Watch his videos on how to use your fish finder.
     
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    MattFred1414

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    When you’re offshore, set the depth scale manually to 300 feet or less. It doesn’t need a bottom lock to see fish in the top part of the water column. Auto-mode is not your friend offshore. Learn your fish finder settings so you can set at least the depth and gain manually.

    EDIT: I’ll give a plug to @Dave Hansen. Watch his videos on how to use your fish finder.
    This was really helpful. I’ll give it a whirl on Saturday when I head out. I guess i had some false information already in my head
     
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    ShadowX

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    Oct 10, 2010
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    I could be wrong, but anything over 900ft the signals won’t make it back to the transducer. So you won’t even see fish suspended 300ft down. I don’t have much experience trying to mark fish in >900ft of water and I thought that’s how it worked.

    You can mark fish down to around 2000+ feet if you have a 1KW transducer at 50KHz. We had some strange marks very deep when crossing over to Catalina at close to 2000 feet.

    The penetration depth depends on three main factors, the frequency, the cone angle and the power level. Lower frequencies penetrate deeper. Large cone angles are good to look for fish around the boat, but limits the depth. Narrow cone angles can go down deeper. The power level is obvious, so higher power units can penetrate deeper.

    The Airmar B175L can penetrate more than 2500 feet deep. They can actually penetrate even deeper, but that is the transducer is spec to.

    Unless you are looking for swordfish, you don't need to look that deep. If the tuna is that deep, you will have a hard time bringing it up to the surface with normal fishing gear.

    Most of us set our fish finders to a fixed depth of around 500-750 deep when fishing offshore.

     
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    ShadowX

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    For you guys in smaller private boats fishing bluefin, what fish finders are you using?

    I have an Axiom 9 which is great for nearshore, but it only reads depths to 900ft. Pretty much useless after that where the bluefin are sometimes.

    If I get the opportunity I’d like to catch a bluefin out of my rig with some flat falls. But I’d have to change up the fish finder setup. What’s your guys recommendation? I have a 20ft bay boat center console

    What and brand type of transducer do you have on the boat? What is the frequency, power level, etc. Is it a chirp or non-chirp model?

    In general, if you are fishing local waters, at various depths below 300-400 feet, its fine to have the depth set to auto. I typically use HDS or Simrad products, but most fish finders have similar settings. Some people set it to manual, but life is too short. If you driving around the depth keeps changing, setting to auto is fine. If you want more information, you can use a fixed depth and make adjustments.

    If you have a chirp sonar and transducer, I set the ping rate to the max level. Turn on your gain until you see the thermocline. Its shows up as a line across the middle of the transducer where the color changes slightly. This is due to the temperature difference between the warmer surface water and the colder deep water. Once you see the thermocline, you can leave the gain in that setting or go up/down slightly. Most fish finders have a TVG setting to reduce the surface clutter due to bubbles, waves, or other surface noise. The Raymarine calls this setting the "Surface Filter". I usually set that around 2-3. The higher the number, the less noise you see, but you may also miss out on some surface fish.

    Once you go offshore, the main setting you want to change is from auto depth to a fix depth. I usually use around 600 feet. This way, it prevents your sonar from trying to find the bottom and keep adjusting the parameters. You can slow your boat or stop it and adjust your gain until you see marks and the thermocline. At this point, you know your equipment is working properly even though its not marking the bottom. Often times, you actually see small fish marks even in the open ocean due to bait and other marine life.

    Get some practice with your electronics if you are not familiar with it. You can play with it in your backyard to get familiar with it. You just need to turn off the sonar because you don't want to have it on when your boat is not in the water. It can damage the transducer. Playing around with the settings lets you know where to look for the buttons when you are in the water. You can preset the settings and look at all the different options that you can adjust once you are back in the water again.
     

    MattFred1414

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    What and brand type of transducer do you have on the boat? What is the frequency, power level, etc. Is it a chirp or non-chirp model?

    In general, if you are fishing local waters, at various depths below 300-400 feet, its fine to have the depth set to auto. I typically use HDS or Simrad products, but most fish finders have similar settings. Some people set it to manual, but life is too short. If you driving around the depth keeps changing, setting to auto is fine. If you want more information, you can use a fixed depth and make adjustments.

    If you have a chirp sonar and transducer, I set the ping rate to the max level. Turn on your gain until you see the thermocline. Its shows up as a line across the middle of the transducer where the color changes slightly. This is due to the temperature difference between the warmer surface water and the colder deep water. Once you see the thermocline, you can leave the gain in that setting or go up/down slightly. Most fish finders have a TVG setting to reduce the surface clutter due to bubbles, waves, or other surface noise. The Raymarine calls this setting the "Surface Filter". I usually set that around 2-3. The higher the number, the less noise you see, but you may also miss out on some surface fish.

    Once you go offshore, the main setting you want to change is from auto depth to a fix depth. I usually use around 600 feet. This way, it prevents your sonar from trying to find the bottom and keep adjusting the parameters. You can slow your boat or stop it and adjust your gain until you see marks and the thermocline. At this point, you know your equipment is working properly even though its not marking the bottom. Often times, you actually see small fish marks even in the open ocean due to bait and other marine life.

    Get some practice with your electronics if you are not familiar with it. You can play with it in your backyard to get familiar with it. You just need to turn off the sonar because you don't want to have it on when your boat is not in the water. It can damage the transducer. Playing around with the settings lets you know where to look for the buttons when you are in the water. You can preset the settings and look at all the different options that you can adjust once you are back in the water again.
    The transducer is a raymarine Rv-100. I’ve played around with everything but the depth so I’ll mess with it when we’re doing some rockfishing on Saturday. I do usually leave it in auto depth because I fish 150ft max normally and it’s always worked. If the bluefin are within range I’d like to try and jig one up. I guess I have the bug now since my last my trip.
     
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    MattFred1414

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    Good advice already given. I will add, turn on your side vision and zoom out till you can see the water column port/starboard to help provide another data point.

    I also highly recommend you watch the Raymarine webinars for tips on how to better use your Axiom MFD.

    Thanks for the tip. I’m going to check these videos out after work
     
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