What is the maximum speed that the p66 transducer with a 620 FURUNO probe can measure the depth?
If your transducer is not subject to turbulence your boat will not travel faster then sound through water. If you are losing bottom at higher speed there is turbulence. You might have to reposition the transducer.

You might want to take a look at this thread from The Hull Truth with pictures of P66 mounting:
http://www.thehulltruth.com/marine-elec ... ading.html
My transducer is parallel to the bottom of the boat, what angle I'll have to use it to mark the depth at speeds exceeding 7 knots? I'll have to make a play for the transducer get this new angle?

Hi Metroncanon,

there is a setup that works for all, the right position of the transducer as well as his inclination may be different each time.
You just have to patiently try to change the angle until you get the best result.