[Anonymous]

I have been having some difficulty calibrating my echo sounder allowing for the offset from transducer to the bottom of the keel. Can anybody tell me what this offset is, I have the deep keel (2.05m) version of the Bavaria 46?

Having made several attempts at getting it right it still can read 0.00m and we are not yet aground. We are Med based and therefore can’t afford a grounding (11 tons takes a lot of pushing). This is my second year with the boat and (touch wood) we haven’t grounded yet but it is quite hairy when you enter a small harbour and the sounder drops to 0.00m.

[Anonymous]

Hello Nick. I am not entirely sure what you mean. Are you trying to set the sounder display to read 0 when the keel touches? If so, you need the distance between the transducer and the bottom of the keel – say about 1.4m – and you enter this into the unit.

The sounder is not always as accurate as the display might have you believe – it does depend on various factors, one of the biggest is the type of bottom. Rock gives a good reading, but softer bottoms give less accurate readings. Muddy water or lots of bubbles is another big factor – try following the ferry up Lymington river and your sounder might well read 0 all the way.

So even if you get the offset right, the sounder might show zero before you touch the bottom.

[Anonymous]

What I’m trying to do is to get the Echo Sounder to read 0.00 when the keel touches. Are you reasonably sure that the transducer to keel bottom is 1.4m?
Nick

[Anonymous]

Nick,
My first attempt at sending this went to you personally and I really wanted it go go on the Forum. So at the risk of repeating myself………

There are a couple of things you could try. Option 1 – I guess lifting the boat out to check the off-set it not an option. Option 2 – When you are next in shallow water, preferrably moored up, where you have a positive reading on the sounder, drop a line over the side to check the depth of water. The depth of water, less your draught is the depth that should appear on the sounder. You should be able to calibrate based on any discrepancy.

Mike Kamara

[Anonymous]

I’ll check what offset I have at the weekend and let you know next week.

[Anonymous]

@kamara wrote:

Nick,
My first attempt at sending this went to you personally and I really wanted it go go on the Forum. So at the risk of repeating myself………

There are a couple of things you could try. Option 1 – I guess lifting the boat out to check the off-set it not an option. Option 2 – When you are next in shallow water, preferrably moored up, where you have a positive reading on the sounder, drop a line over the side to check the depth of water. The depth of water, less your draught is the depth that should appear on the sounder. You should be able to calibrate based on any discrepancy.

Mike Kamara

Often best to drop a line both sides to ensure that the bottom isn’t sloping.

Ed

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