Do you calibrate you depth sensor to water level or keel?

[EmeraldCoastSailor]

Mine came to me calibrated to water depth minus a foot and I never messed with it. I know to expect a bump when it reads less than 4'.

[lo2jones]

Water depth is easier for navigating and anchoring. One only adds the height of the bow roller to calculate the scope before dropping the hook. With water depth, there are only two numbers required for navigating, with keel depth there are three.

[wibi]

I go for water depth - easier to work with charts & tides. Put on a depth alarm and mzke good use of my B&G forewardscan ti avoid running into trouble

[pcmm]

Originally Posted by lo2jones

Water depth is easier for navigating and anchoring. One only adds the height of the bow roller to calculate the scope before dropping the hook. With water depth, there are only two numbers required for navigating, with keel depth there are three.

Actually the calculation is identical. With water depth you add the bow roller height ( which has to be prederemined) to the water depth. With Keel offset you just add the height of the bow roller to the bottom of keel (also has to be predetermined) + read depth

just different ways of looking at the same thing.

[Bargain Bill]

the only thing that matters is depth under the keel. If you want to compare waterline to the charts it's easy to add the keel depth in which case you must then take into account the tide. Whatever you choose, it should be noted on the display.

[mjadczyk]

Originally Posted by Lodesman

Charted depth doesn't necessarily take tide into account.

I use keel depth - when it reads 0 I expect a bump.

Same with me. I can calculate depths from the chart when required, but sailing in tight spots requires an immediate read of the actual depth under keel.

[Tom1080]

Water level: As it helps confirm where we are when looking at the chart depths and also for determining amount of anchor rode. I know our boats draft is 1.5m and I have an alarm set for 1.8m.

[gwyn]

Prefer keel although have done both.

It is the non-thinking option especially if you are tired after long or difficult passages.

Also makes anchoring depth calculation easier as it turns the rule of "fud" into the rule of "**" (no insult intended).

[RnJBSailing]

We are in the Great Lakes so no tides to worry about and only in/out of rivers have any significant current. So given our sailing grounds we set ours from keel (which is 4'6"), we set it to 5' so we a little safety. We don't have to subtract the keel from waterline depth constantly to know if we are ok! Lake St Claire is shallow, except very high water years the last couple years, so we don't want to take time for our old brains or guest "Captains" to do any math!

[Tom1080]

Hi Lodesman.. There was no assumption of your incapacity to do mental arithmetic I was just replying to the OP of what we do and why it suites our sailing. I totally agree there are advantages of the below keel method too. There's no right way or wrong way from what I have read.. just the boat's way.

[aqfishing]

[/QUOTE]

If you set it to anything other than water depth, make sure you put a big sticker next to it saying so, as anyone else on your boat won't be expecting that.[/QUOTE]

I would say its safer to set to water under the keel. That way you have a safety factor if anyone else helms.

As for charts. Most tropical places when you that shallow have no soundings anyway.

Its easy to check tide difference and relate it to whats under your keel.

[Amapola]

Depth under the keel.

[RaymondR]

Who cares how deep the water is as long as there's some left under the keel.

In the place I normally cruise the tide can be up to almost 7 metres (23' or so) and it's simpler to check the range and state of tide and calculate minimum under keel without having to consider depth of keel when coming to anchor.

[searenity38]

I use water line depth. My transducer doesn't read depths less than a couple of feet very well so if I read from bottom of keel and I'm getting into skinny water I could be 1, or 2, or 3 feet off. Plus I like to compare to chart soundings. Just my 2c

[moseriw]

Water level of course - to compare with maps!