Unreliable Depth Sounder

My Raymarine depth sounder seems to lose the bottom from time to time (5-10% of the time), often in shallowish water. Seems to occur when trimming bow down, or changing speed but it's really quite intermittent and annoying.
I've had my diver focus on keeping it clean but it still happens.

During my next haul out I'm thinking of installing a back up transducer and depth sounder (not Raymarine!)

I've been told that there are good ones that actually read through the hull. This would be nice and I won't need to put another hole in the bottom. Whatever I decide I want a reliable read!

Also, where is an ideal location for such a thing?

Any suggestions? Thanks.

Beneteau should be able to help-give them a call or email

Sounding thru the hull (solid GRP , no core) works but will reduce the depth readable by quite a bit.

If you are in 40 ft , no big deal, looking for the bottom out on the shelf , big deal.

Sounds like perhaps air entrainment is screwing the reading on the existing unit.

Maybe a high speed fairing block would help part the waters from air at slow speeds if air bubbles running under hull are interfering.

sdowney717 said:

Maybe a high speed fairing block would help part the waters from air at slow speeds if air bubbles running under hull are interfering.

Click to expand...

I have one transducer that has the fairing block and another one that shoots thru the hull. Both work good. It's just a matter of keeping undisturbed water on them.

Many times in shallow water it is one of many factors such as sediment, vegetation, thermocline, etc that can cause a depth finder to lose bottom. Sometimes adjustments can filter these things out. sometimes not.


Can't be totally sure...but pretty sure Raymarine transducers are made by AIRMAR who also makes just about everyone elses...especially the nicer ones.


I have a Raymarine shoot through the hull that is definitely AIRMAR, it is one of the new tilted element ones, it is installed correctly and once and awhile it will lose bottom for a few seconds or so.


If you have a thru hull ducer, it only takes a tiny bit of growth to give erratic readings.

Ours was becoming less sensitive over time, and ultimately wouldn't work in water deeper than 50 feet or so.

I was well on my way to finding a new depth sounder when I thought to check the cable connection at the back of the display unit. As I was moving the cable aside to get a better look, I noticed the display sparked back to 100% brightness and detail, then went back to being all screwy in an instant.

Hooking the cable over something created a loop which realigned its entrance into the display unit and the darn thing has been perfect ever since.

Maybe your issue has a similar origin...might be worth checking and cleaning all the connections from transducer to display just in case it is a similarly simple (and inexpensive) fix.

If you are going to shoot through th hull, make sure to put the transducer in a spot with no core. It won't work through cored hull.

Good suggestion about making sure all connections are tight. I will be replacing my old Datamarine depth finder next week with a new Garmin 741xs and tilted thruhull 'ducer. I thought the old Datamarine was shot because it wouldn't power up. Lo and behold after chasing some wires and finding some minor corrosion in the fuse holder for the power into the unit, it started up and is working fine. Now I'm wondering if I can use the old Datamarine with a shoot trough the hull 'ducer as a back up. Any way bad connections are very common on boats. lol.

Kevin

I had lots of shallow water problems cased by wake disturbance, sediment etc. Always in shallow water when I needed it most. Several brands of digital depth sounder on different boats all were unsatisfactory.


The solution for me was a double frequency scanning display fish finder. The scanning display shows bottom profile and trend and will give some data even if the digital depth number display cant get enough signal.


I doubt a new xducer will solve your problems.