Furuno sounder reading

[pete76]

I have 2006 furuno sounder with a 1kw thru Hull transducer, it reads the bottom well and picks up baitschools of fish no worries but I can never mark kingies(arches) or mark any fish on my sounder. I turn the gain high, try Lo/hi freq etc but still can’t mark fish.

I know the fish are there cause I’m catching them but can’t mark them. What am I doing wrong? How do I rectify this?

 

[Croydon]

Hi mate.

What model Furuno are you using?  When you say you 'can't mark fish' what do you mean?  Do you get any readings at all?  It's not unusual for fish not to show up as the classic arch and there are many reasons for this,  Do you have any photos of the soundings you are getting?  I've been using a Furuno FCV585 and TM260 transom mount transducer for years.  I rarely if ever get fish arches but it marks fish/bottom at 25knts and down to 550m (at a very slow pace).  Don't be too hung up on the whole 'arch' thing.  When I'm catching kings they come up as solid red marks and or elongated red lines depending on how they travel through the transducer cone.  Hope this helps. 

Dave 

[noelm]

I don't quite get the question, if you are catching fish, just keep doing what you are doing, what the sounder shows doesn't matter if you're doing OK.

[JonD]

Are you using 200khz or 50khz. For me 200 nods to around 300m where deeper I have to go to 50khz.

I had an airmar tm260 which I sold on eBay due to the 200 cone angle being so narrow it missed many fish, I also didn't see any improvement deep dropping when running side by side tests with Lowrance deep water $300 transducer.

Screen resolution can be a big part of not seeing fish arches, wide screens with very little res in the down direction will struggle compared to a deep screen with with higher res. One way to overcome this is to manually set both upper and lower scanning limits. Even in 300m I can see fish and my deep drop tackle by simply using a smaller amount of water for my entire screen. To do this I set my upper limit at say 280 and my lower at 310m if in 300m of water. This way all of my res is being used for just 30m instead of 300m +

For general snapper and kings in depths to 80m my sonar finds fish very well due to a big deep 12 inch screen. I notice Garmin have considerable more res in one of their 10 inch screens than in my 12, which will be my next purchase.

I rarely see true arches but more squiggly lines for both kings and snapper. Those dence bloobs of bait with squiggly mess around them are what I'm searching for and not clean perfect arches like in the advertising brochures.

What I've noticed on a friends furuno is that the bottom often shows close to the middle of his screen and not at the bottom of the screen, meaning the already low res has been halfed which most definitely accounts for showing less fish. Say this was happening in 50m of water and he manually set his max depth to 55m, the bottom would then be almost on the bottom of the screen. Let's say the top 15m is full of interference and clutter so we set the surface to 15m this will then increase the detail being used where fish are most likely to be. 

A few years back I was working on a fishing charter boat where the boat had an old wide furuno sounder, fishing over an area I regularly fished. I asked the owner how he finds fish without seeing them on the screen and he said by just trying every bump on the bottom he found. I asked why he doesn't adjust his screen, which he replied " I just switch it on and that's it" . 

He then said have a fiddle with it if you like and once I adjusted as mentioned above the owner flipped out like a 4 year old at Xmas. Suddenly those very subtle bumps looked a whole lot bigger and not only that but fish appeared too. Afterword I did wonder if I had done the right thing given his impact on the same areas I fish!!!!!

 

in this old screen shot you can see what's a large bump on the see floor where the zoom is being used for one part only. On the right hand side of the screen  you don't notice the bump at all due to using the full water depth, the fish were gem fish. This is from an old Lowrance hds 8. 

 

 

 

Edited July 13, 2019 by JonD

[pete76]

Thanks all, couple of weeks ago when the bite was on in middle harbour I was amongst half a dozen boats catching 1m kingies in 20-25m of water, multiple boats hooked up within meters of each other, nothing would show on my sounder but the downrigger bomb and the bottom, other guys I spoke to were looking at their sounders and marking fish then dropping jigs on them, their screens were lit up with multiple arches/red lines. With so many large kingies amongst us I was very surprised to have my sounder not show anything.

catching Yakkas the bait balls show up very well on my sounder.

Only time I remember marking kingies was at the 12mile in about 110m of water where I saw arches at the bottom, dropped jigs down and caught 2 kings. Perhaps as you said the angle of the cone is the issue? Can this be adjusted?

 

Cant remember what model they are but here’s a pic I found on my found.

 

ill try adjusting the surface and bottom depth and see how I go, any other tips would be appreciated 

 

cheers

peter

[JonD]

That is weird you can see the downrigger and not fish, is the downrigger a strong signal and can you pick it up in 60-80m.  I would of thought even if the angle is off you would see fish if you can see the downrigger.

With in hull and through hull transducers there's a mark to show which direction to point the transducer when fitting it. Also if it's placed on the v of the hull the correct degree angle needs to be purchased to match the hull, something doesn't sound right here.

I assume that image on the right is your sounder, which looks odd as as can't see a strong bottom return from it.

Just to be clear is the transducer sitting in the hull or is it cut through the hull?

Edited July 13, 2019 by JonD

[PaddyT]

Peter i believe there is an Australian Furuno owners FB page that one of the Furuno Australia tech guys frequent. They might be able to help you out with your particular problem- i never have issues with my Lowrance (not starting a brand discussion here) but agree with above comments-kings tend to show as streaks across the screen for me- this is an indication that they are moving at a reasonable clip (as they do)- good luck.

[pete76]

JonD i should clarify i can see the bomb when i come to almost a stop not when going at 2-3knots. i haven't tried past 20m down but very clearly picks it up. Baitballs clearly show up at any depth. At browns mountain it can just read bottom upto about 450m and thats it.

The transducer is cut through the hull not in the hull.

 

 

[Nolongeramember]

15 hours ago, pete76 said:

Thanks all, couple of weeks ago when the bite was on in middle harbour I was amongst half a dozen boats catching 1m kingies in 20-25m of water, multiple boats hooked up within meters of each other, nothing would show on my sounder but the downrigger bomb and the bottom, other guys I spoke to were looking at their sounders and marking fish then dropping jigs on them, their screens were lit up with multiple arches/red lines. With so many large kingies amongst us I was very surprised to have my sounder not show anything.

catching Yakkas the bait balls show up very well on my sounder.

Only time I remember marking kingies was at the 12mile in about 110m of water where I saw arches at the bottom, dropped jigs down and caught 2 kings. Perhaps as you said the angle of the cone is the issue? Can this be adjusted?

 

 

There is nothing wrong with your sounder. You didn’t see any fish because there were none directly under you. That’s why you can see your bomb at rest but not when travelling slow because it moves back, away from the beam. 

The Furuno has a slightly narrow beam angle so you won’t see arches, just a line or “marks” when a fish is under you. 

I have the 585 and it’s a brilliant sounder  

 

[Berleyguts]

This is interesting. I only saw genuine arches in any quantity for the first time on my Humminbird when I fished at Broughton Island with @Scratchie the other week. He pointed them out on the sounder - I’d never seen so many before! I had adjusted my settings to try and fix a depth alarm problem I had. Maybe I fixed two things!