Datamarine Depth have erratic readings

[Bob Early]

I inherited a sailboat with a good set of Data marine instruments.Lately the Depth meter readout is very erratic. It seems stable at on moment (lets say 25 feet), and then the next few moments iut is reading any where between 2 and 75 feet and multiple numbers in between.I have to assume the more stable number is the real depth, and the erratic readiings are due to something being in the water in between the sensor and the bottom. It seems like it should settle down faster than a few minutes, though?Any suggestions on what I ought to be looking for first?Thanks,Bob

 

[Debo Cox]

Funky Depth Readings

Hi Bob,I think you're on track with the way you're thinking about your depth finder.What I've found is that basically ANYTHING between the transducer and the bottom can cause erratic readings - even things I didn't originally suspect. These can include:a. A fouled bottom on your boat (most likely)b. Underwater bubbles and turbulence (wake, etc)c. Underwater grasses and vegitationd. A change in bottom consistencye. Schools of fishAnother possibility is that some depth finders have a "range" setting - for instance "10-20, 20-50, 50-100 feet" You might check that. What I've learned to do is kinda what you alluded to - I study charts of the area I'll be cruising in, and use the most frequent reading on my depth finder as one of many tools I use to not run aground. Hope this helps.

 

[Vic Suben]

Data Marine problem

I have the same problem, except mine might read 179 feet in water I know to be no more than 20 feet. It seemed to work better after I dove under the boat & wiped it off. When Mystique comes out of the water I will inspect the transducer to see if there has been an accumulation of something that is interefering with its operation.

 

[james rohr]

erratic read outs

you did'nt say which inst. series you have. I have the corinthian s200 series and when I'm seeing erratic readings usually just a minor adj of the shallow gain solves the problem. since you can't put bottom paint on the transducer,which will interfer with the readings, I put a coating of silicone grease on mine in the spring. this is water proof and keeps the growth off for the season. if no coating then it needs to be cleaned periodically. hopefully you have the transducer that can be removed while the boat is in the water. if not then I guess you'll have to get wet periodically to clean it.good luck.Capn jim of Que Pasa?

 

[Charlie on "kestrel"]

Cable

Bob,This season I've had erratic readings on my depth sounder too. What I found to be my problem was the cable from the transducer to the meter. I took the connections apart and cleaned them. Salt atmosphere and electrical connections don't go together. Have'nt had a problem since.Good Luck