side scan sonar transducer mounting Plus camera mounting

Ok.  Dreaming of upgrading equipment.  First potential upgrade is a  side imaging sonar.

My understanding is a side imaging sonar can't shoot thru hull for what seems like obvious reasons. 

My first ah-ha solution was to bolt the transducer directly onto the rudder.  I rarely need to lift my rudder up in any kind of hurry.

Does anyone else use a side imaging sonar and if so, where do you mount the transducer, and what was your feel for how well that worked for you?

Second Topic: Underwater camera.

I have arriving Monday a Vexilar Fish Phone underwater camera.  It's basically a small underwater camera with 50ft of cord.

For this application I was considering a mount that would be anchored into the sailing mast mount, then protrudes forward past the bow, then a bar into the water with the camera.  If needed, I could rotate the arm to come off either side of the kayak.  I may set it up so I can also lower the camera farther down though I don't think it would be nearly as stable unless I weighted the camera end down sufficiently like a down rigger ball. 

Of course the default is to just mount it onto the down rigger ball but with just 50ft, it'd be limited and frankly a pain in the butt if I was also using the down rigger for fishing.

Any ideas here?

I've been using the 798ci for a little while and really like it.  I have the transducer mounted on a RAM transducer arm and so far I'm really happy with the transducer arm.  It's much more robust that I originally thought it would be.  The only problem with it is getting weeds caught on it.  The return for the side scanning is amazing!  I originally used the Lowrance mounting system that Hobie has but found that it introduces a slight amount of attenuation for most of the range of the side scanning, and full attenuation for the far sides of the side scanning range since the mount is positioned above the bottom of the hull.  Mounting on the rudder may be a pretty good idea. 

I have the same fish finder/transducer mount as rawkfish.  I am happy with the ram transducer mount.  It folds up out of the way when transporting the kayak.  It does however create water noise as you peddle/paddle-at least where I located my arm and transducer.   The imaging is great especially with no electrical interference/noise created by the kayak. 

  Mounting on the rudder may be a pretty good idea.

How would that extra weight impact you retracting the rudder into the upright position?

Between the weight of the tranducer and the stiffness of the transducer cable, I don't think it would work on my Hobies. 

  Mounting on the rudder may be a pretty good idea.

How would that extra weight impact you retracting the rudder into the upright position?

Good question. But if I had it, I think I could deal with it. I rarely come flying in while raising the rudder. It's either calm and I pedal in with everything down (but rudder unlocked) or I take the time to raise it and paddle in.   Worst case I could probably mount in a way where I could pull on the camera cable (secured in such a way so it doesn't pull directly on the connection) and lift.

I figure it can't be a whole different than the motors I've seen attached to the rudder...at least I thought I saw a motor mounted that way.

But if the boxes and ram or Scotty mount works, I may try that first. But while trolling a 8lbs downrigger ball with full 11 inch sized flashers and king gear, I already introduce tons of noticeable drag so I'm a little sensitive to any additional drag.


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Side scan sonar sends out signals at right angles to the centerline of a boat.  If the boat travels in a straight line and at a constant speed, the sonar screen will show an accurate representation of the bottom features and fish the boat went past.  However, if the boat makes a gradual left turn, the images on the sonar screen will be distorted, in that the images on the right side of the screen will be spread out, and the images on the left side of the screen will be squished together.  If the left turn is sharp enough, the images on the left side of the screen may backtrack over objects the boat went past earlier, creating a confusing sonar image.  If your kayak is pitching and slewing around in large quartering waves, the side scan image may get pretty jumbled, just as ordinary sonar may show a series of bumps on the bottom as you ride over large waves in fairly shallow water.

A rudder turns more quickly and irregularly than a boat.  When you are trying to maintain a boat on a straight course, you may need to move the rudder to the left and the right to make course corrections.  If your side scan transducer is mounted on the rudder, it seems to me that each time you move the rudder you'll distort the image on your side scan sonar screen.  And because it may be difficult to remember the pattern of your rudder movements, it seems to me that the sonar image will difficult to interpret.  So it seems to me that your side scan sonar will be more useful and produce more understandable images if you mount its transducer on your kayak, rather than on the rudder of your kayak.

Side scan sonar sends out signals at right angles to the centerline of a boat.  If the boat travels in a straight line and at a constant speed, the sonar screen will show an accurate representation of the bottom features and fish the boat went past.  However, if the boat makes a gradual left turn, the images on the sonar screen will be distorted, in that the images on the right side of the screen will be spread out, and the images on the left side of the screen will be squished together.  If the left turn is sharp enough, the images on the left side of the screen may backtrack over objects the boat went past earlier, creating a confusing sonar image.  If your kayak is pitching and slewing around in large quartering waves, the side scan image may get pretty jumbled, just as ordinary sonar may show a series of bumps on the bottom as you ride over large waves in fairly shallow water.

A rudder turns more quickly and irregularly than a boat.  When you are trying to maintain a boat on a straight course, you may need to move the rudder to the left and the right to make course corrections.  If your side scan transducer is mounted on the rudder, it seems to me that each time you move the rudder you'll distort the image on your side scan sonar screen.  And because it may be difficult to remember the pattern of your rudder movements, it seems to me that the sonar image will difficult to interpret.  So it seems to me that your side scan sonar will be more useful and produce more understandable images if you mount its transducer on your kayak, rather than on the rudder of your kayak.

This is a REALLY good point.  I can't believe I never thought about that and now I'm glad I didn't pursue that idea any further.  Having the 'ducer on the rudder would give you a really shitty picture. 

And that is exactly the tremendous value this board provides!!!

Great point!!!!!!!!


AlaskaKayakFisher.com
Guidesak.blogspot.com
My personal pages...I'm not a guide.

Lol. Now I'm going to mount the under water camera on to the rudder so I can point It in Different directions as it looks forward under the kayak.

The info provided may have killed two  birds with one stone. Any issues here???


AlaskaKayakFisher.com
Guidesak.blogspot.com
My personal pages...I'm not a guide.

I really like the covered transducer pocket in the bottom of recent-model Hobie kayaks.  The pocket does a great job of protecting my transducer, and ordinary sonar and "down imaging" sonar work very well with the transducer in the pocket.

If side scan sonar doesn't work well when the transducer is mounted in the transducer pocket because the hull of the kayak blocks sonar signals going off to the sides of the kayak, and returning from off to the sides of the kayak, perhaps you could develop a "pop-down" mount for your side scan transducer.  This would involve removing the cover from the transducer pocket, and developing a mount for the transducer which would let you move the transducer down out of the pocket to a point several inches below the bottom of the kayak.  You'd reach behind your seat and push down on the mount to move the transducer down out of the pocket.  This seems like it ought to work.  It would be easy to temporarily mount your transducer below the pocket to see how well your side scan sonar works in that position.  Removing the cover from the pocket would slightly increase the drag of the hull of the kayak, but the transducer would be quite well protected when it was in the pocket even without the cover.

The risk of a "pop-down" mount is that if you forget to raise the transducer when you come into shore, you could bang up your transducer and bust the mount.  So it would be a good idea to develop a mount which would rise or swing out of the way if the transducer hits something.  If you construct a "pop-down" mount which slides straight down through the scupper hole which leads to the transducer pocket, if you hit something, the mount would probably break before the transducer could get pulled up into the pocket, even if it is spring-loaded with a catch which would pull the mount straight up if the transducer hits something.  So it would be better to construct an articulated mount which would automatically swing back and up into the pocket if the transducer hits something.  The mount could be like the arms on an anglepoise lamp, so the transducer would remain parallel to the bottom of your kayak whether it is inside the pocket or below your kayak.  There isn't much room for such a mount in the pocket.  The way I'd do it is to have the upper end of the articulated arm attached at the bottom of the scupper hole, which is located at the front of the pocket, and to have the lower end of the articulated arm be attached above the stern end of the transducer.  It would be tricky to fit all this apparatus into the pocket, but it might be possible.  If anybody is interested, I could e-mail them a sketch of the idea.

A disadvantage of a "pop-down" mount is that it would pick up weeds, and removing the weeds while you were out on the water would involve some contortion. So it would also be desirable to develop an angled fin or rod which would guide any weeds around the transducer.

I posted this video in another thread but didn't want to hijack it.

So I tried out the vexilar fish phone.  Not sure what to think.  It records in 240P...major suckage...It's terrible in low light. Strike two,  But it did work as advertise and I had fun using it while ice fishing.  It seems to work MUCH better in more light so open water might be ok. 

In the second video, you see one section is in color.  I guess it automatically switches to color if there is enough light.

First day was dark and dray even at noon.  Second day was a little better.  Both were in about 10 feet of water....

Resolution sucks so I wouldn't maximize the screen.  Gets super grainy.  But it did save my neck and back from peering down the hole all day long.  I wonder how long before I kick my iPad down the hole.....

Not sure why there is dead video at the end of the second clip...