Depthsounder malfunction

[Lou 14643]

Just back from a wonderful three day sail on the Chesapeake - consistant 10-15 knot southerly winds, beautiful weather! (except for the lunatics in their Cigarette boats - did anyone else see these guys flying down the bay today?Here's my problem...My new in 2004 Raymarine depthsounder has been working great for three seasons. For the past month or so, however, it has been getting quirky. Usually when coming in to a shallow anchorage, it may suddenly lose data, display "- - -" or sometimes flash a depth instead of showing a steady reading. Does not seem to correlate to weedy areas, speed of boat, whether under sail or power, or any other repeatable condition I can think of. I've disconnected the leads, cleaned and reconnected them. No corrosion I can see. I get great, steady data when underway (for over five hours today) but sure enough, when coming into my marina, I lost the readout for a few minutes and then regained it again. Anyone have any ideas before I try with the Raymarine folks? I've studied the manual, but it does not contain much in the way of troubleshooting. By the way, bottom is clean - I hauled the boat two weeks ago, and cleaned what little growth there was. The transducer is in-hull, not through-hull. I installed it in 2004 when my old unit failed, and bedded it, I believe in Marine Life, or similar product recommended by the yard in Oxford where I made the repair.

 

[Ross]

Lou. I have an Apleco and it goes crazy every

now and again. The alarm goes off and Nancy gets panicy but it is just a floating weed or two. We have been alying at anchor and had the alarm go off because a raft of weeds slides past.

 

[Benny]

How did you bed the transducer?

A transducer cannot transmit through air, so if air has gotten in the hull or inbetween the transducer and the hull you may get a no read signal. This is just a possibility for you to verify. Some transducers are encased into a base filled by water or oil and if air finds its way into the base they will malfunction. I have used epoxy in transducer applications which much success as they do not develop leaks or get air. Good luck

 

[Paul (Affinity C320)]

Raymarine Depth Sounder

I have the ST60 Depth Sounder and it does the same thing, New in 1999. I think it is either air or bubbles. I see it as no big deal as it alwayscomes right back.Paul

 

[RichH]

Sensitivity setting/adjustment

Most Raymarine and other depthsounder have an adjustment (usually in their CALibration settings section of their control software) that desensitize the instrument. The --- means that the reading (near zero) has become unreliable .... possibly due to gelatinous bottom where sometimes the signal is sometimes bouncing off the 'real' bottom and sometimes off the upper layers of the goo/gelatin, ditto the same thing when going through beds of grass .... sometimes off the bottom and sometimes off the top of the grass, etc., sometimes off the bottom and sometimes bounding off of air bubbles near the bottom, etc. etc. etc. Look in your owners manual on how to de-sensitize your depthmeter, etc. for a correction.

 

[Lou 14643]

Thanks for all the responses...

Ross, you've pegged our picture. When I'm out by myself I watch the chart, water and proceed with caution. My boat only draws 3'. When with my wife, as I was this weekend, she starts to get anxious (understandably) when display goes blank. I try to calm her, but I can see in her face that she's remembering time 18 years ago, she was 8 1/2 months pregnant, we ran aground off Ft. Howard and had to be pulled off by County Police launch. I had been asking her to lean out over the side to heel the boat to no avail!Benny, the transducer is bedded in some kind of silicone/caulk product. Don't remember the name, but it was highly recommended by the yard I was at (Hinckley in Oxford!) and has given good service up to now, so I don't think that's it.Paul, my problem is that the signal does not always come right back. I was anchoring on Friday evening in Reed Creek (off Chester River) and soon after entering the creek I lost the signal and it did not come back until motoring out the next morning. Rich, your response makes tremendous sense to me, and I'll pursue how to adjust sensitivity, if I can. I even commented to my wife that I wondered if diffent kinds of bottom might be affecting the response. This would reinforce for me the observation that I always get consistently good deep water readings (over about 15-20 feet). I'll play iwth it next weekend (won't get back to the boat 'til then) and let you know. Thanks all for your feedback! This site is always terrific!!

 

[s sauer]

False Bottom Readings

I used to have the same problem in a 3' draft Hunter 25 typically in mucky bottom areas. Don't remember the Manufacturer of the unit for sure , probably DataMarine. Try to find a senstivity adjustment; but I would re-scrub the bottom in the area of the transducer as well. Two weeks is enough to start reasonable slime growth on the hull.We had an interesting time trying to get across to the Easternshore with about 50 GoFasters comming up the channel in front of Tolchester at about 1530 hrs on Saturday. Just figure that if all thos guys keep buying gas at over $3.00/ gallon, maybe the marinas will not raise their rates so often on the rest of us (yah sure)!

 

[Warren Milberg]

Depth sounder malfunction

I had a similar problem with the depth sounder on my old C&C, which was a very old unit. Since this malfunction always seemed to occur in one particular segment of the Bay (south and east of Rose Haven), I thought it may have something to do with some huge Navy radome/antennas that live in this area. These devices can put out some interesting interference, IMHO. After a while I was able to mark off a fairly large quadrant on my chart in which I would get the depth sounder malfunctions and assumed the radomes were the culprits. You may want to check your boat, and the area you sail in, to see if you too could have a land-based culprit causing your depth sounder malfunction.And since your transducer is in hull, not thru-hull, I doubt the source of problems would be a fouled bottom. A properly working depth sounder, in any event, would shoot through fiberglass with ease so fouling should not be a problem. Since you've cleaned all the connections, I would guess your problem may be due to corrosion inside one of the wires to/from the transducer, or inside the readout unit itself. Another area to check would be the bedding you used for the puck. If that bedding has any air bubbles in it, you could get bad readings due to that. It may be worth while to remove the puck, clean up the old bedding and either rebed it there with new sealant, or to find a new spot to bed it.

 

[JC on Bainbridge]

Could be prop wash from another boat

When we are out on the boat, if we go over an spot where another boat under power just went through, we would get shallow readings, sometimes even 0. Once we are through that area, it is ok again.Also, depending on the season, there may be lots of algae, bloom, or other stuff in the water, and that can give you bad reading too.

 

[Lou 14643]

Again, thanks for more thoughtful responses

S. Sauer and JC, there were several crabbers working the creek we anchored in Friday (Queenstown Creek). One guy had a board mounted on his transom which he slid down (sort of a perpendicular daggar board) whenever he was working his trotline. It slowed him to a managable speed, but I'm sure also stirred up the bottom quite a bit and may have caused some of the turbulance in the water that you suggest could be a problem. Warren, I have not been too close to the area you mention lately, but will keep my eye out for that effect. By the way, I've enjoyed your writing in SpinSheet. Thanks very much for that!I've looked at the documentation for the unit on Raymarine's web site, but don't see anything about adjusting sensitivity, so I've emailed their tech support folks about this, and will see if they have any advice.Thanks again, all!

 

[RAD]

Very Interesting Lou,

I have a Garmin chartplotter with a seperate sounder attached and started having the exact same symptoms,I've checked every thing except swap my unit with a friend who has the same setup.I think it might be a software glich cause I've started to go though menus to see if its still hooked up to the sounder and then it comes back to life after a few key strokes *o but not every time.and my transducer is through hull and clean

 

[BrianW]

Same Problem With My ST-40

It only happens for a couple of minutes every now and then and corrects itself. I did notice the "increasing" and "decreasing" depth arrows also go crazy. Maybe some rapid depth variations or as others suggested... weeds or other sea life (jellyfish?). BrianW

 

[Ross]

My depth sounder is an Apelco fish finder.

The alarm is set for six feet. It is mounted under the boat on a skeg. It is designed as a transom mount unit. It is mounted on the center line about 6 inches deep. It shows bottom contours and bottom conditions. Grass and submerged aquatic vegetation (SAV) shows up as noise on the screen and sets the alarm off. Quite often we leave it on while we are at anchor just to hear the beeps as the fish go by. Occassionally a raft of SAV floats by and the alarm goes crazy. I have had to clear the mess with a boat hook.