Raymarine Dragonfly

[diver 1]

I've fitted a Raymarine Dragonfly with CHIRP downscan imaging to my rib as supposedly an upgrade replacement of my Lowrance unit.

The Raymarine unit works nicely when stationary and upto speeds of 8 knots but then I lose all bottom tracking regardless of downscan or sonar mode.

I knew there would be some messing with transducer positions to get optimum and had quite a fiddle to get the Lowrance perfectly working, but this thing is a joke. I've resorted to using 3M sticky pads now to mount it in different positions for testing rather than holes. My next resort must be to fit the stupid thing to a piece of timber and G clamp the timer to the top of the transom so I can keep adjusting it whilst on the water until I find the elusive position that works.

Has anyone else had bother with these Raymarine transucers? Would be very grateful if anyone would share pics of a successfully installed transucer that works above 8knots!

Thanks

[hoss]

I have one that will work up until 20 mph. I made a bracket that extends out past the hull into cleaner water about 2 inches. I will try to get a photo for you but basically it is a stainless flat piece about 2 1/2 in wide bent into a c shape with a flange at the top and bottom.

Had same problem as you. Make sure the center line of the transducer is level with the bottom of hull. Transducer is large enough to affect sharp turn cavitation depending on which side you mount it.

H.

[diver 1]

Thanks Hoss, that makes sense about the turning cavitation. I've not tested it in calm water yet, each time I've been out its been 4-5ft minimum sea state. I guess the water movement just caused by crossing these waves would maybe be enough to upset it.

I think I get what you mean about the bracket. I need to figure a way to temporarily mount it with G clamps or similar until I get the position fine tuned. Moving it back from the hull makes some sense, but then closer to the prop too..?

[hoss]

Just make sure the bends of the flanges are exactly the same angle as your transom is. In other words just an extension of the transom.

Take a straight edge from the hull back and make it hit the center line of the ducer.

That will tell you about where to put your bracket, the locking cogs on the ray bracket should have a setting at level. Once you take off, the water pressure will lift the ducer up slightly to make it run level with the water not the hull.

Hope this makes sense. I spent 15 dollars to make mine work.

[hoss]

Sorry forgot to say not behind a chine and as far away from the prop as you can.

Away from elephant trunks.

[paintman]

Fitting it to the end of a length of wood & adjusting using a G-clamp should give you more of an idea - I take mine off the main boat & mount it exactly like that when pike fishing at Rutland Water in the winter on one of Rutland's hire boats. You might want to consider shaping the front of the wood to avoid it creating its own turbulence.

I've had no problems on my own boat - 17' Dory - with the Dragonfly mounted where the old Humminbird was at speeds including low speed planing similar to hoss - providing the transducer is in the water & not in turbulence caused by the hull. At speed no reading but that's not surprising as there's not much of the hull in the water anyway!
It's as low as I dare put it as the boat takes the ground at low tide.

[diver 1]

Interesting point will profile the sides a bit depending on what I use. Pole shouldn't need to extend past the hull and the bracket itself gives a lot of downward reach anyway.

Still cant get the thing to display actual GPS position all the time. I was hoping to be able to switch on a text box permanently in the corner of the screen displaying lat / long.

Never mind.

[paintman]

Make the wood long enough to reach down below the hull. Be interesting to see what difference that would make.

[diver 1]

Ok will do. Needs a lot of experimentation. Next question is Sonar Logging. I can save Sonar Logs for use in updating Navionics Charts etc but can I save an extract a sonar log from the device myself I'd like to map a small area of Seabed I am interested in diving on and produce my own 3D map from scratch using a 3D AutoCAD software I have

[paintman]

Sorry, I'm afraid I have absolutely no idea!
(I should perhaps add that the main use for mine is for the sonar/downscan facility for fishing & the GPS is largely for marking locations for that purpose so navigation is primarily to waypoints/known locations)