raymarine dragonfly 4 unreadable past 7 knots

Hey guys, can anyone help, basically when out on the water my sounder works well at around 6 knots then becomes unreadable after that, what things can I do to improve. 

ranmar850's picture

Posts: 2608

Date Joined: 12/08/12

water turbulence, prop noise or gain (or all three)

Wed, 2019-08-07 15:29

 Make sure the transducer( assuming a transom mounted skimmer type) is the right height. The lower face  should be in the water when you are planing, and angled ever so slightly forward. If you have too much gain on, general hull and prop noise will wipe you out when you put a few revs on. By unreadable, do you mean broken up and noisy, or just a mass of strong colour? A screenshot would help.  


Posts: 49

Date Joined: 10/12/14

 Yeh a just a mess of colour

Wed, 2019-08-07 15:45

 Yeh a just a mess of colour and sumtimes cant find the bottom next time im out i will take a pic and also check the gain. I did notice last time I was out that the transducer was a little loose so have tightened it and hopefully this makes a difference.

Swompa's picture

Posts: 2788

Date Joined: 14/10/12

I had to mount (silicone)

Wed, 2019-08-07 19:00

I had to mount (silicone) mine in the sump. Shows bottom up to 20 knots now but I am yet to catch anything that it suggests is a fish

Posts: 49

Date Joined: 10/12/14

 Quick update I tightened my

Mon, 2019-08-26 08:20

 Quick update I tightened my transducer mount and pointed it down and managed to have readable ground at 17 knots so pretty happy with it