Fish/Depth Finder Issues?

[JenMarie]

Does anyone know who or where I can take my depth finder to get it calibrated? I have a RayMarine L755c unit that was working fine. I had some trim tabs put on the boat and it appears they had to move the transducer and now I can't get a fish arch to read nor does my depth indicator work reliably? The boat shop swears they did nothing wrong but you know how it goes.... the thing worked fine before they touched it. I did a reset of the head unit but that still didn't do anything. Now I can be in 60ft of water and have a shallow depth alarm go off and vice versa. I come up to the boat ramp and the depth is marking 24ft. Any thoughts or suggestions would be appreciated. The boat is trailerable so I can pretty much take it anywhere. I live in Tracy but I am all over the Delta (and sometimes in the Bay). I'd hate to buy a whole new system if it's something simple like a new transducer or a bad connection or something.

John

 

[AbsoLoot]

John,

The new trim tabs are probably creating turbulence or air bubbles that is interfering with the sounder. How does it work when sitting still? Is the transducer still completely under water? Does it seem to be perpendicular to the bottom?

 

[abdiver]

Is it a through hull or a transom mount?

I am guessing that it is a transom mount and they had to move it because of a physical interference with the tabs. If they didn't relocate it to a good spot then you might have a lot of trouble.

If it is a location issue then I would expect it to read properly when sitting still and perhaps at dead slow speeds. If it is directly behind something that creates a disturbance in the water (such as the keel, water pickups, etc.) then it might not be able to read properly while underway.

It is also possible that it just needs a slight adjustment. Older units would have a physical "pot" that you would need to turn while newer units typically have the "gain" setting in software and changed through some use of the front panel. You will probably need to get the owner's manual to figure it out, but if your display has a "menu" option and then perhaps a "setup" I would try that. You would need to increase the "gain" or "Sensitivity" setting.

Rod

 

[JenMarie]

The transducer is a transom mount. It doesn't work real well when standing still either. The transduces is actually lower in the water then it used to be since they moved it down and more towards to motor. Just flashes the depth either at 0.0 or whatever the last reading was. I will try to change the gain and sensitivity settings to see if that helps. I've done the basics of making sure everything is tight and secure and clean and still nothnig better from a performance standpoint. Thanks for all the info.

John

 

[DeltaDawg]

If it doesn't read the depth well when it is standing still in water they may have strained or broken the wiring when they moved the transom mounted transducer. You should be able to find a new transducer with Google buy it and the correct length of new wiring to your depth finder.

The trim tabs are going to change the flow of water around the transom in various operating modes so I think it is time to go with another transducer mounting method.

I have a transom mounted tranducer and it does not read well on plane because of the turbulance around it. My boat only uses 6 inches of draft so I live with the problem. My boat is plywood, fiberglass cloth and epoxy so I had to go with the transom mount or a thru hull and there was no way I was putting a hole in the bottom of the boat I hand crafted.

When I mounted my transducer (Hummingbird) I remember reading about how for a solid fiberglass boat hull you could mix up a puddle of 2 part epoxy and set the transducer in the puddle on the inside (bilge area). If your boat bows up in certain operating modes you would want this to be located on the aft bottom where there is always water under it. You also want smooth laminar flow on the water side so check out the water side while it is on the trailer and look for a flat area where the water is going to approach it longitudianlly with no turbulance. If you have a big heavy inboard motor in the bilge it might be difficult to put the epoxy puddle where you want it. If I had a solid fiberglass boat though I would try gluing one on the inside before I went with a thru hull and put a hole in the bottom of my boat. If the epoxy puddle mounted transducer doesn't work you abandon it in place, try another location with an new transducer or go with the thru hull mounted transducer. Good luck.

 

[Flutterby]

Trim tabs were added to my fiberglass boat years after the transom mounted depth finder. My depth finder works the same with as well as without the trim tabs. The transducer did not have to be moved when the trim tabs were installed. If properly mounted, the transducer should not have interference from the trim tabs.