Camswan sidescan sonar images

[Andy135]

Got a few drifts over the Camswan in Sandown Bay the weekend before last. Here are a couple of pics, one at 455khz, the other at 800.

The banana shape of the first and last pic is because I was trying to correct the drift half way through - doh! Still decent pics though.
She's a hungry wreck... I lost 3 rigs on her in 3 drifts. Afterwards I did some research online and apparently she's known for having 4-5m tall beams running along her centre line, which can be clearly be seen in the last pic. No wonder I was losing tackle.

[Steve S]

Well that's a good use of side scan, well done

[lofty]

I can never get my head around what i’m seeing on them. Is the centre line the sea surface and the images to the left and right of where you are?

[mw]

Hi Lofty the centre line is the boat the darker section is the depth of water below the boat the image left and right are out to the side 60 either side

[Andy135]

2 hours ago, lofty said:

I can never get my head around what i’m seeing on them. Is the centre line the sea surface and the images to the left and right of where you are?

 

These are birds eye view images (top down). The centre line is the blind spot directly below the transducer. It shoots either side of the boat but can't see directly below, hence the blind spot in the image. So in the first pic, the wreck was to the left of my boat as I drifted alongside it.

 

The dark areas either side of the centre line is the water column but not directly down, rather it's the water between the sea floor to the left and right of the boat, and the transducer itself.

[Gazza]

Hi Andy,

 

great pics,

 

If the dark area is the water above the wreck am i right in saying the small white flecks in the dark area are fish above the wreck?

 

I am with lofty with the side scan technology.....totally lost although you are making it a lot easier to understand

 

Gary

[Andy135]

55 minutes ago, Gazza said:

Hi Andy,

 

great pics,

 

If the dark area is the water above the wreck am i right in saying the small white flecks in the dark area are fish above the wreck?

 

I am with lofty with the side scan technology.....totally lost although you are making it a lot easier to understand

 

Gary

 

Hi Gary, it's hard to say if they're fish or not. In the last image the white scatter at the bottom of the pic was my wash as I manoeuvred the boat whilst drifting. In the first pic its possible that the brighter specks could have been small baitfish, but with sidescan you can usually tell it's a fish or not by its shape; a fish will show up as a  bright, elongated shape that looks vaguely like a fish seen from above. The specks in the pic seem more circular, so it's not clear cut.

 

Here's an example of how fish show up on sidescan. This isn't my image (I just Googled it) and the shoal is in much shallower water, but you can clearly see the fish (tarpon) in the water column and their sonar shadows on the sea floor. I wouldn't expect this level of detail at the depth we fish over wrecks in the UK, but I would expect to see the rough shape of the fish.

 

[Andy135]

Here's another Googled image that shows more clearly how a single fish shows up on sidescan. Note how shallow they are (8ft) which is one of the main reasons why the fish shows up so clearly, and so large. Fish at our depths will be much smaller and harder to identify.

 

[lofty]

I see a topic / slide show demo for our members at a club night?


Sent from my iPhone using Tapatalk

[Andy135]

1 hour ago, Gazza said:

Hi Andy,

 

great pics,

 

If the dark area is the water above the wreck am i right in saying the small white flecks in the dark area are fish above the wreck?

 

I am with lofty with the side scan technology.....totally lost although you are making it a lot easier to understand

 

Gary

 

One other point to add when looking for fish. In the UK it's rare that we have single large fish showing up on their own on a sonar image. We're more likely to see fish in small shoals... and this is often the best way to be certain that there are fish down there. If they show up as a shoal of bright spots/ovals, then it's probably worth dropping a line. If you can only see one or two isolated spots then a) they may not be fish, and b) even if they are, there are only a few of them so perhaps not worth trying to target them individually from 20m+ above.

[Steve S]

Those images you googled are very impressive, note however the sonar operating frequency 1.1 to 1.2mHz. I don't know of any normally available sonar equipment that work at that frequency, please correct me if you do. The higher the frequency the higher the image resolution and generally the less depth they will work to. Also tarpon are big fish, they are going to show up well even on a 50khz outfit as a large inverted U.

 

[Andy135]

22 minutes ago, Steve S said:

Those images you googled are very impressive, note however the sonar operating frequency 1.1 to 1.2mHz. I don't know of any normally available sonar equipment that work at that frequency, please correct me if you do. The higher the frequency the higher the image resolution and generally the less depth they will work to. Also tarpon are big fish, they are going to show up well even on a 50khz outfit as a large inverted U.

 

 

Yes, I noticed that too. They're from Humminbird's new Mega range. I believe they're the first manufacturer to introduce megahertz frequencies to the recreational boating market. https://www.humminbird.com/learn/imaging/mega-imaging

 

You're right about higher freqencies. Generally the higher the freq = the higher the res but water penetration suffers = shallow water only. You can see on my images that the 800khz image is much darker and harder to interpret than the 455khz image and this is why I don't anticipate UK anglers needing to invest in the megahertz range - the water we fish in is simply too deep for it to be useful. In the US bass fishing market I can see that it would be beneficial if you're fishing shallow lakes (<10m depth) and hunting for individual fish that are hiding around submerged structure, but that's not our style of fishing.

 

And finally, yes, tarpon are big fish - sadly not representative of our UK fishing but included as an example to illustrate how a fish shows up on side scan. I'd love to see something that size on my FF in the UK but it's unlikely. Pack tope maybe...??

 

[Rob]

Get yourself down west for some blues, i'll switch on my side scan when i am down there next (although old Lowrance Gen1) - prob not this year ☹️

[Gazza]

Thanks Andy,

these are amazing images, 

at the moment i have a basic in-hull transducer on my boat until i research what type of decent transducer i need for a simrad go 12,

however im not sure if the side scan tech is for me lol.

 

Im doing lots of looking on youtube but it seems to always be on USA lakes.

 

do you use the side scan when trying to find ....say bream can you identify the nests ?

 

I would love to see some pictures of the sharks Rob ( I hope you get to go soon)

 

Gary

 

[Andy135]

34 minutes ago, Gazza said:

Thanks Andy,

these are amazing images, 

at the moment i have a basic in-hull transducer on my boat until i research what type of decent transducer i need for a simrad go 12,

however im not sure if the side scan tech is for me lol.

 

Im doing lots of looking on youtube but it seems to always be on USA lakes.

 

do you use the side scan when trying to find ....say bream can you identify the nests ?

 

I would love to see some pictures of the sharks Rob ( I hope you get to go soon)

 

Gary

 

 

Hi Gary,

 

The US is the major market for sidescan, which is why most of the marketing material and videos are aimed at their style of fishing.

 

As for bream, yes. SS can identify their nests; they show up as clusters of circular patterns on the sea floor. I may have a pic somewhere that I'll dig out.

 

As for transducers, your Simrad Go should be compatible with any of the transducers from Navico, the parent company of Simrad, Lowrance and B&G. They have two transom mount SS transducers worth considering at present. Active Imaging 3-in-1 or TotalScan.

 

If you're evaluating whether to invest in SS, then I'd say that if you only ever fish the marks that you already have then you probably don't really need SS. But if you like to scout around for new marks or like to see what wrecks look like then SS is a good tool because you can search much wider swathes of the sea floor vs regular downscan sonar. It makes pinpointing wrecks much easier or spotting structure that could be a fish holding feature.

[Rob]

@Gazza

[Andy135]

Some nice sharks and great footage there Rob. 👍

 

What make is your boat?

[Rob]

It's a Terhi, Finnish built and and plastic.

 

R

 

 

[Andy135]

On 6/6/2020 at 8:35 AM, Andy135 said:

 

Hi Gary,

 

The US is the major market for sidescan, which is why most of the marketing material and videos are aimed at their style of fishing.

 

As for bream, yes. SS can identify their nests; they show up as clusters of circular patterns on the sea floor. I may have a pic somewhere that I'll dig out.

 

As for transducers, your Simrad Go should be compatible with any of the transducers from Navico, the parent company of Simrad, Lowrance and B&G. They have two transom mount SS transducers worth considering at present. Active Imaging 3-in-1 or TotalScan.

 

If you're evaluating whether to invest in SS, then I'd say that if you only ever fish the marks that you already have then you probably don't really need SS. But if you like to scout around for new marks or like to see what wrecks look like then SS is a good tool because you can search much wider swathes of the sea floor vs regular downscan sonar. It makes pinpointing wrecks much easier or spotting structure that could be a fish holding feature.

 

@Gazza, bumping this up as I took a side-scan screenshot of bream nests over the weekend and thought I'd update this thread.

 

Here you can clearly see the bream nesting sites showing as circular, honeycomb-like structures on the right hand side of this sonar pass. I was scouting around for a new mark on the weekend as my regular spots were already taken. As soon as I spotted these I dropped a line over and bingo! Fish first drop.

 

 

Full report over on Outlaws in case you want to read it: https://www.offshoreoutlaws.co.uk/topic/2357-may-14th-on-the-bream/