Autohelm Depth Sounder Problem

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Guest

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My boat is fitted with an Autohelm Tridata and I am having problems with with depth reading when the boat is planing.

Basically the depth reading flashes showing the last recorded depth which can go on for some time, which is obviously quite worrying.

The manual says that this is due to turbulence around the transducer but offers no other reason or cure.

I am not able to move the transducer so has anyone else had this problem and do they know a cure?
 
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Guest

Guest
Yes, I have the same problem from time to time, but in open water it's ok. Somewhat uselessly, I have no clue as to how to stop the gauge flashing when it loses the ability to correctly read the depth. This at least forces one to read the charts, and simply "know" the depth of everywhere on a trip, which the depth guage sometimes shows, and sometimes doesn't.
 
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What is the length of your boat? And exactly where is the speedo fitting sited?
 

Scubadoo

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Not much help, I got round this be having two depth sounders (Tridata and Garmin 240). I didn't do this for that particular problem more to do with diving. However I notice that if one starts flashing (lost reference) the other is still working okay - to my knowledge I have never had both "flashing".

My Tridata transducer is fitted underneath the hull.

RM.
 
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Guest

Guest
hi,
an autohelm ST50 tridata look at the depth sender is it a through hull type?
is it Black plastic?
if the snswer to those two questions is yes then you have 2 options.
1 take the boat out of the water and replace the plastic sender with a brass one.
the ange the sender is sitting at may be too much the brass ones have a greater working anle
2 you can now get a through hull depth transducer to fit the ST50
plug it in to your ST50 head set the boat up to the speed you have the problem and with a bag of water between the transducer and your hull move them around till you get a good steadt reading it is also worthwhile checking throughout all speeds. Keep the tranducer and cable away from engines and other electronic equiptment as these can confuse the signal.
you can contact Raymarine formaly ratheon who bought out autohelm or contact Tony Martin Electronics on 01603 712334
 
G

Guest

Guest
Apart from what you have been told by the rest of the sages who have responded, there is the question of depth and speed. Basically your sounder bounces a "ping" off the bottom. The deeper it is, the longer the ping takes to come back. If you add to that the speed of the boat through the water, in effect you can have moved the transducer out of range of the return echo. There are a number of things which can reduce the sensitivity of the transducer and exacerbate this effect such as

a) Its location on the hull and whether it is vulnerable to turbulence/aerated water around it. You could try moving it.

b) Check (assuming a through the hull i.e. internal transducer) that the oil bath is intact and that it has not quietly leaked away. If any part of the transducer head is exposed it will seriously reduce performance.

c) Check it is aligned properly. If it is "off" the vertical the bounce from the bottom does not come straight back but centres somewhere else.

If you know you are in deep water, try going slower to see if that restores the reading.

For me the main use of the sounder is when berthing or approaching a berth as in my cruising grounds there are very few stretches of open water where there is the slightest chance of the bottom being less than 50 metres distant. Obviously one can use the sounder to help navigation by finding a depth contour on the chart but in these days of GPS and other nav aids, who does? It is mostly used to sound an alarm when you are getting close to the green bits on the chart!

Nick
 
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Deleted User YDKXO

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Neil, I had this same problem with a Tridata and a through hull transducer. I take it you have a through hull transducer not an in hull one? I used to lose the depth reading at anything over 15knots
I have recently fitted a Raytheon (ex Autohelm) in-hull transducer which has completely solved the problem giving a correct read out at all speeds. As another poster has said, immerse the new transducer in a water filled plastic bag, connect it to the Tridata and move it around the hull until you get good readings at all speeds. My boat is shaftdrive and I found that the best position was about 3 feet ahead of the sternglands on either side of the hull. Once an optimum position is found, the transducer sits in an oil filled tube siliconed in position
 
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Deleted User YDKXO

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Call me old fashioned but I like to see a number on the depth sounder when I'm doing 20knots. It's sort of comforting. A blip on a screen is still a bit too virtual reality for me without relating it to physical features. I often do a quick mental calc of what the depth should be where I think I am at that particular moment and if the sounder says something different I start to wonder why
Without being too dramatic it saved me last Saturday afternoon coming out of St Malo. There are so many physical features in the area that a quick glance at a plotter screen does'nt instantly tell you where you are; I was helming manually and trying to avoid a melee of peche promenades and I missed seeing a crucial green buoy. A very basic pilotage error. Luckily for me I glanced at the sounder, saw 5m instead of about 20m, stopped and worked out where I actually was which was about 100m short of piling the boat onto some French granite at 20knots. Saved by the sounder
 
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