Shallow depth alarm

[opie]

In a recent topic by JimmyT he described a wonderful sailing day in a J while in occasional areas of shallow water.

Some years ago I discovered that same issue while trying to sail my Mac in the larger expanses of the ICW here and small bays and inlets.

I was watching YouTube sailing one day long ago when I saw one sailboat's crew alerted to upcoming shallow water by means of a loud siren going off at a preset adjustable depth.

At the time I had a Hawkeye depth finder gauge that had a low depth alarm. But the weak little piezoelectric horn was pathetic. I couldn't hear it at all under sail. (my granddaughter could...)

So, I researched depth alarms for ones that had auxiliary outputs rated to control a large waterproof siren. Nothing found. I even called the Hawkeye company in Georgia and spoke to head of tech and while he was very polite, he said no product that did that.

So, being an old EE, I voided the warranty on the Hawkeye, opened it up and found the piezoelectric horn solder pin and soldered a small TTL logic output wire to it with the wire going to a 10 amp separate relay. Then I got a waterproof burglar alarm siren, 90db, and installed it inside my helm pedestal.

That was 10 years ago or more.
The alarm was set for 4 feet. It has helped me numerous times.
Plus it saved my life one time while my mind wandered as I was going 15 kts down the ICW. The ICW can get wide and then narrow quickly. I was headed out of the channel and maybe to a pier when the siren jolted me to turn back to the channel.

Last summer, north of here, news was of a poor youth who lost his life running into a channel marker. Perhaps, such an alarm would have saved him.

At that time I pitched my alarm idea to the Coast Guard and local wildlife officials. Nothing proprietary, I said.

And I sent a video to Hawkeye. "What a great safety product!" I expressed to them and told them to expand their capabilities. I asked for nothing in return, for in fact, any high school science teacher could do it.

Crickets from one and all.

If anyone is interested, let me know and I will pass on info.

Opie

[Jimmyt]

In a recent topic by JimmyT he described a wonderful sailing day in a J while in occasional areas of shallow water.

Some years ago I discovered that same issue while trying to sail my Mac in the larger expanses of the ICW here and small bays and inlets.

I was watching YouTube sailing one day long ago when I saw one sailboat's crew alerted to upcoming shallow water by means of a loud siren going off at a preset adjustable depth.

At the time I had a Hawkeye depth finder gauge that had a low depth alarm. But the weak little piezoelectric horn was pathetic. I couldn't hear it at all under sail. (my granddaughter could...)

So, I researched depth alarms for ones that had auxiliary outputs rated to control a large waterproof siren. Nothing found. I even called the Hawkeye company in Georgia and spoke to head of tech and while he was very polite, he said no product that did that.

So, being an old EE, I voided the warranty on the Hawkeye, opened it up and found the piezoelectric horn solder pin and soldered a small TTL logic output wire to it with the wire going to a 10 amp separate relay. Then I got a waterproof burglar alarm siren, 90db, and installed it inside my helm pedestal.

That was 10 years ago or more.
The alarm was set for 4 feet. It has helped me numerous times.
Plus it saved my life one time while my mind wandered as I was going 15 kts down the ICW. The ICW can get wide and then narrow quickly. I was headed out of the channel and maybe to a pier when the siren jolted me to turn back to the channel.

Last summer, north of here, news was of a poor youth who lost his life running into a channel marker. Perhaps, such an alarm would have saved him.

At that time I pitched my alarm idea to the Coast Guard and local wildlife officials. Nothing proprietary, I said.

And I sent a video to Hawkeye. "What a great safety product!" I expressed to them and told them to expand their capabilities. I asked for nothing in return, for in fact, any high school science teacher could do it.

Crickets from one and all.

If anyone is interested, let me know and I will pass on info.

Opie

Great idea! I'm surprised Hawkeye or Raymarine, etc hasn't come out with a depth instrument with an aux output jack for a remote alarm connection. Seems like it would minimally impact the per unit cost. They could manufacture an aux alarm/strobe assembly to sell to compliment the depth sounder. Guess that's why we're engineers and not marketing types...

My thought is, it would probably help you at 5-7 knots. On a jet ski or power boat at 25 knots, the alarm might not give you enough warning to take action.

I just got a downward imaging sonar / depth instrument, and am noodling over the possible mounting locations for the transducer. Is there an advantage for putting the transducer in the bow? Don't know if it would be worth the trouble if there is an advantage...

I like your hack! And I always admire someone willing to void the warranty!

[kurz]

My problem is even more basic: I use a triducer that sends directely to the raymarine ev-100 display.

So where I could connnect a beeper at all?

[Inquisitor]

I was talking to my brother-in-law (avid fisherman) where sonar is more about seeing fish... I was telling him I'd like to get something for depth warning. I wasn't sure if its possible to put the transducer low enough (above the ballast) tank in the front where it can even work. And even if it is low enough while sailing, it'll certainly be out when planing. He says, high speed bass boats actually put it on the transom because that's the only point that's still in the water at full speed. He gets practically no look ahead warning there even though he has all the underwater terrain view thing.

[Be Free]

The Garmin 700 series has an output wire that will go low when the alarm is sounding. It is rated at 100ma max so I doubt you could drive a speaker from it but you could trip a relay that could drive the speaker.

[NiceAft]

If you're at open throttle,or close to it, you're probably moving too fast to react safely from a sudden threat from below. When sailing, my eyes are basically fixed on what's ahead, and I'm looking for changes in the water surface.

I had a scare several years ago that keeps me from straying out of the channel. Unless I have to, I stay in the channel.

I was on the Delaware River, and outside of the channel markers. Ahead I saw a log. I purposely avoided it, but went close enough to observe it. What I saw was not a log, but rather the top of a very large pylon from some long ago something. It was low tide, and this was just barely above the water. At a not much higher tide, this is completely submerged. If I hit it, the damage to my would have been catastrophic. Since then, unless I have to (commercial vessel bearing down, etc.), I stay in the channel.

[opie]

BeFree:
You nailed it. "Going low" is exactly the pin I used. Since it had no spec to alert me to load I could not trust to use it directly so I used it to trigger a NPN transistor and that in turn ran my 12 v relay.

[Neo]

This is a great idea ... And I need to investigate what my Raymarine can output.... The only downside I see (with a loud siren) is every on the lake gets to know that your'e just about to crash ... but that could be a good thing too

And here's something that might help those folk that do not (or cannot) want to void their warranty.
Late model iPhones (iOS 14>) now have a "Sound Recognition" feature which in turn can sound an alert on the phone ... Regrettably I cannot vouch for it at this time because I'm on Ver.14.1 and it crashes every time I go into that menu ... but maybe that's been fixed on Ver.14.2? ... https://www.howtogeek.com/693029/how-to ... on-iphone/

Hope this information helps/saves someone

[Inquisitor]

Where do you all put the transducer?

[Russ]

Where do you all put the transducer?

Mine is mounted on the transom. If doing it again, I'd probably mount in close by inside the hull.

[NiceAft]

Mine is also mounted on the stern. I figured that since we float in a foot of water, and always stay in the channel, I'm fine.

When I moved up to the Garmin GPS map 700 series, I had to buy a transducer for that unit specifically.

[Jimmyt]

Wrapped up the install of my birthday fish finder. It has a depth alarm which I'm anxious to check out. The way I fish, unless the fish finder can cast and reel, I'm not sure it will help. But it will be fun to watch the imaging.

Used an epoxy coated oak block glued to the transom to attach the transducer. Didn't want to drill the transom below the water line if I didn't have to.

[NiceAft]

Several years ago, I was sailing Lake George, NY. There were four of us on board. I suddenly noticed that the Garmin showed hundreds of fish 60-100 feet down. I didn’t say anything. I went beliow, got my boat rod; attached a large lure and a 3 ounce weight. I just let it drop. Our guests were wondering. I guessed what was enough to let out, and began to slowly retrieve. When an almost two foot long lake trout showed, I was shocked. There was no fight what so ever. From that one fish, we all ate well that night.

[Russ]

Several years ago, I was sailing Lake George, NY. There were four of us on board. I suddenly noticed that the Garmin showed hundreds of fish 60-100 feet down. I didn’t say anything. I went beliow, got my boat rod; attached a large lure and a 3 ounce weight. I just let it drop. Our guests were wondering. I guessed what was enough to let out, and began to slowly retrieve. When an almost two foot long lake trout showed, I was shocked. There was no fight what so ever. From that one fish, we all ate well that night.

I'm sure your guests were perplexed at your magic.

[Russ]

I like this vs drilling a hole. Very nice.

Mine is mounted in the same place. My only concern is that I can't back onto a beach else risk ripping it off (and opening a hole in the hull where it's attached)