Depth Gauge

Never had to do this but believe you should 'adjust' according to where your sensor is in relation to your keel.
If you just have a reading of 2M and you have a draught of 1.5M it can be critical as to difference in position of sensor to keel.
 
I set it to read depth of water, so when it reads 2m, you're aground!
I have been caught out by visitors on the boat expecting it to read keel clearance.
It would be nice if the instrument label could be changed to 'TOTAL DEPTH' or something so one could instantly see which it was!
 
Doesn't really make much difference as long as you know which it is. I haven't offset mine, working on the principle that if it is on the default it can't be inadverantly reset, it gives depth from the transducer. It is also a Seafarer rotating dial type so reading is + or - half a metre isn't really reliable anyway.

I think once you get down half a metre or so of your draft it is pretty academic anyway as you only get the depth under the transducer not the entire boat - there can easily be half a metre difference in depth between the bow and the stern. The seabed isn't even and it is likely that the water is going to be shallower forward of the transducer and deeper aft of it if you are entering shallow water anyway.
 
Good point, as I said I have not had to do this as at the moment as my boat is a few metres above water level whilst being rebuilt, so just going from instructions in manual with my Seafarer which was already fitted to boat. But as you say half metre is neither here nor there.
 
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as you say half metre is neither here nor there.

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Depends where you sail. Last year I sailed for about 0.8 of a mile with the echo sounder giving 0.2m below the keel. I wish I could get my kitchen floor that flat! (Just outside Harwich, between Pye End and No2 buoys, near LW, dead calm.)
 
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Mine is set to show depth of water. Easier that way all round. No complex sums to do.

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Yep, entirely agree! Much simpler all round. I tried depth below keel but, with a mooring up the River Tamar, found my heart rate running far too high too often!! /forums/images/graemlins/smile.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
 
Mine shows water under the keel. Zero is zero and it displays in feet and decifeet. so when I get to 0.5 I'm preparing to groove the mud. I just go slowly at these times.
 
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Entirely agree. Mine is set to read from the bottom of the keel. Alarm set to bleep when there is a metre or less under the keel. Mouth starts to go dry at 0.3 metre. /forums/images/graemlins/laugh.gif

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Don't go down the French Canals then!! /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
 
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If you use the offset does that mean that the sounder can show a negative depth?

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Tried that but mine will only show positive numbers. If below zero it shows zero!

Idea was to set depth at keel depth plus safety margin and then have a buffer zone but on thinking it through decided it was better to know what was under there!
 
You can choose - just so long as you know what you have done. The advantages and disadvantages become obvious when people come on board who are used to a different system.

Ours is set as depth of water and is in metres. It agrees with the charts plus tide, and if I can't remember that I need 1.8 metres to float in then perhaps I shouldn't be on the water.

I can't understand those who say setting at depth below keel makes the sums easier. If you are navigating using depth and have the e/s set as depth below keel, then you have to do sums all the time, and are always adding on 1.6 metres or whatever it is. The only sum you have to do when it reads depth of water is "is it bigger than my draught?" How much bigger is usually not such a critical question.

However if it works for you...
 
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