Raymarine C80 & DSM300

[RustyTank]

2004 28TE... Raymarine C80 & DSM300 with B744VL transducer... Factory mounted to port of centerline...

System generally works great... but have LOTS of trouble maintaining bottom lock while at cruising speed... (18-19kts)...

Any ideas?... I've messed with every gain, TVG, Frequency etc... I cruise in relatively shallow water 90% of the time (less than 40ft in Southern Chesapeake - Home Port Norfolk/Little Creek)...

At slow speed tracks fish and bottom great... just at a loss to keep an idea of water depth at cruise...

HELP!

// RustyTank

[Serenity]

"less than 40 ft." Several of us AOG guys boat on Great South Bay, Long Island, where the average depth is 6-8 feet. The shallow depth creates a problem with readings with the bottom all kicked up because of the ferries. We do see 40 plus feet at the inlet, then it goes right back up to 10 feet./ I have a C-70 which works better when the depth is over 15 feet and cruising at 18 knots. Have you tried making sure the fittings are all secure and made tight on the DSM 300 and the back of the C-80. Mind have at times back off a bit and the readings were a little off. Ray Marine has a great service department. If you can not figure it out, send it back to them, and perhaps they can do a little tweaking.
Little Creek, spent 3 1/2 years there. Great place.