Deep water alarm on depth sounder

Steve Laume · Post by **Steve Laume** » Jul 27th, '10, 07:27

Okay so I have a new depth sounder and it has a shallow as well as deep water alarm. I know what to do with the shallow water alarm. That is the one that will make a bunch of noise before the boat goes bump.

Liz and I were trying to figure out what we would do with the deep water setting. The only thing I could come up with was setting both alarms to sail depth contours but all the buzzing would get very annoying.

What do you do with a deep water alarm?

Creative as well as functional answers would both be appreciated, Steve.

Carl Thunberg · Post by **Carl Thunberg** » Jul 27th, '10, 08:48

More functionality than I ever needed. I suppose if you're fishing Jeffrey's Ledge (for example) and want to be warned if you stray from the ledge it would be helpful, or if you want to avoid straying into a deep draft shipping lane. For most of us, it's completely useless. Oh, and did I mention it's also amazingly annoying?

Neil Gordon · Post by **Neil Gordon** » Jul 27th, '10, 09:39

As a nav tool, it's not just about following contours where you try not to let either the too deep or not deep enough alarms go off. You might set the "more than" alarm to alert you when you pass a given depth... that could confirm (or adjust) a DR track.

Setting both can also be used as an anchor alarm. You know where you are and you know the tidal range. More or less than that and perhaps you're no longer where you dropped the hook.

Jack Carr · Post by **Jack Carr** » Jul 27th, '10, 11:59

On a related note, what causes a depth finder without a deep water function to go off for no apparent reason in 100 foot water?

Cathy Monaghan · Post by **Cathy Monaghan** » Jul 27th, '10, 14:03

Remember that line in the movie Blazing Saddles?

"Badges? We don't need no stinking badges."

That's how I feel about those alarms. "We don't need no stinking depth alarms." So we don't use either one. They're just annoying. If you're paying attention to where you are and where you're going, and you really should be, you don't need the alarms.

It's like driving a car -- look out the windshield, glance left, glance right, glance in the rearview mirror, glance at the dash and start all over again. Look forward, look under the headsail, look all around, glance at the masthead fly, glance at the chart, glance at the GPS, glance at the knotmeter, glance at the depth gauge, and start all over again.

Cathy
CD32 Realization, #3
Rahway, NJ
Raritan Bay

Neil Gordon · Post by **Neil Gordon** » Jul 27th, '10, 17:51

Jack Carr wrote:On a related note, what causes a depth finder without a deep water function to go off for no apparent reason in 100 foot water?

Honest, you don't want to know. If you ever actually knew what was swimming under your boat, you'd stay home.

(Either that, or it's just a school of teeny little fish. A thermal layer might also might mislead the depth finder.)

Neil Gordon · Post by **Neil Gordon** » Jul 27th, '10, 18:19

>>"We don't need no stinking depth alarms." <<

Cathy's mostly right. Know where you are, check the chart, check the depth, resolve the differences.

Using the depth meter as a collision (with the ground) avoidance device is bad practice. That said, I do like having it for those occasions where I might be distracted.

bottomscraper · Post by **bottomscraper** » Jul 27th, '10, 18:38

Big fish, little fish, whales, seals, submarines...

Our old Datamarine was very sensitive to bubbles from the prop of other boats that crossed our path. Our newer Raymarine not so much.

Personally we do keep our shallow water alarm set to a couple of feet below the keel. If you have one why would you not use it? Should I turn off the smoke alarms in my house because I am real careful with fire? I'm not arguing that it somehow takes the place of prudent navigation, it just doesn't make sense to me to not use all the tools you have at your disposal.

On our previous boat we had a fish finder rather than just a depth sounder. The fish finder gives you a graphical view and an indication of the type of bottom (hard, soft). It also gave you a good idea what caused a false alarm. Very kewl in my book, wish we still had one.

Jeff and Sarah · Post by **Jeff and Sarah** » Jul 27th, '10, 19:32

i'd imagine the deep water alarm could be used almost as an anchor drag alarm. If there should be about 15' where you are anchored at high tide and your alarm suddenly alerts you to a 30' depth, you know something isn't quite right. I doubt it would do much good underway.

Steve Laume · Post by **Steve Laume** » Jul 29th, '10, 08:19

I think I have a pretty good idea now. It is mostly for whale and sub alerts. Ha, and those sub sailors thought they were quiet enough that no one would know they were there.

I never considered using it for an anchor alarm but it would make a lot of sense in an area that didn't have a huge tidal range to set deep and shallow. The GPS anchor alarm is probably much more effective.

I finally launched Tuesday and had preset the shallow alarm for 8 feet. I figured that was when I would want a wake up to keep a really close eye on things. Twelve might be better but then it would be going off all the time.

Of course it wet off in the shallow mooring field and was indeed rather annoying so I shut it off. It may well stay off all season unless I set it right about keel depth.

From all past experience, I know that by the time I get into water that would set off the alarm I am already very much aware of the depth sounder readings. If you are in water that shallow the last thing you need is another annoyance, Steve

Cathy Monaghan · Post by **Cathy Monaghan** » Jul 29th, '10, 11:39

bottomscraper wrote:.....If you have one why would you not use it? Should I turn off the smoke alarms in my house because I am real careful with fire? I'm not arguing that it somehow takes the place of prudent navigation, it just doesn't make sense to me to not use all the tools you have at your disposal.....

If your local sailing grounds are on a relatively shallow bay, that dang alarm will never stop sounding, really, it's constant -- especially at or near low tide. I don't know anybody who could put up with that. So it really is useless. Do I want to know the depth? Yep. That's what the display and the charts are for, and believe me, they're well used.

Oh, and never turn off your smoke alarm. If it goes off constantly, and there's no fire, there's something wrong with it and it needs to be replaced.

Cathy
CD32 Realization, #3
Rahway, NJ
Raritan Bay

Steve Laume · Post by **Steve Laume** » Jul 29th, '10, 15:13

One of the reasons I replaced our old depth sounder is that the alarm would sound if someone sat in front of it! without actually touching it?

I do not know how this could have effected it but the thing had demons within so nothing was surprising. The keel offset would also change without my awareness and that was troubling at times too.

I think the alarms will stay switched off on the new one and it is far smaller and more simple in general. The old one had an alarm set up that would sound if it sensed a rapid decline in depth. Tha could have been helpful if it had been reliable.

The new one is much smaller and is now reading through the hull so I no longer have the gigantic fairing block and it is cute, Steve.

rtbates · Post by **rtbates** » Jul 29th, '10, 16:00

sometimes you might drag anchor into deeper not shallower water. would be nice to know.. that's what I use mine for...

The Cape Dory Board

Deep water alarm on depth sounder

Deep water alarm on depth sounder

I ignore it.

Alarm in deep water

Blazing Saddles....

Re: Alarm in deep water

go off for no apparent reason

Anchor Alarm

Re: go off for no apparent reason