Sailing without depth sounder?

[Notyetsinking]

So little back-story, I tried connecting my computer to my nmea-0183 network via usb and somehow caused the entire system to go down. With Labor Day coming up, and un-sure of when I will be able to get new sensors put in (given long wait times for service work), how cautious do I need to be sailing around?Our plan was also to be staying in the well marked areas of the Chesapeake Bay, and I've gotten a gps system set up that has millimeter level accuracy with double redundancy, so it is not like we will be sailing blind. We are going to buy a hand-held depth as a back-up for the skinny areas, but we really don't want this to stop us from using the boat. Is this a bad idea?

[Chotu]

You are definitely all set. Just stay in the deep water as shown by your chart plotter.

Don’t worry about going to buy a depth sounder. Tie a weight on the end of a string. When you are in shallow water or to check depth for anchor scope purposes you can just use the lead line.

Confession. I haven’t had a working depth sounder probably 75% of the time I have been boating. And that’s about three decades. They never work for some reason or another.

Just go out of your way to stay in water that is plenty deeper than you need.

When it’s time to anchor, go to a spot that has plenty of depth also.

[SailingHarmonie]

People sailed boats for thousands of years without sonar. You can too.

I have no idea why you would want "millimeter level accuracy" on your GPS or how that helps, but the only thing I would have would be a lead weight on a string to measure depths at the spot I was going to anchor. Otherwise, sail carefully, and be doubly careful at high tide. The Chesapeake is almost all very soft mud so even if you screw up, its not a big deal.

[George_SD]

You can put in a an in-hull sounder connected to a portable fishfinder like the Garmin Striker 4. It will give you depth and comes with everything you need. Costs $120 and can use it for fishing on your dinghy as well It will actually mark fish, not just show depth. One requirement - non-cored location.

I use a CHIRP fishing transducer set in the bilge with a dollop of wax in front of the keel, it's connected to my Axiom chart plotter - works great and reads to about 400ft. It's a cheap low-power transducer that came with the unit and I can put a more powerful one if i want to, but.....why bother?

[Notyetsinking]

Originally Posted by Chotu

You are definitely all set. Just stay in the deep water as shown by your chart plotter.

Don’t worry about going to buy a depth sounder. Tie a weight on the end of a string. When you are in shallow water or to check depth for anchor scope purposes you can just use the lead line.

Confession. I haven’t had a working depth sounder probably 75% of the time I have been boating. And that’s about three decades. They never work for some reason or another.

Just go out of your way to stay in water that is plenty deeper than you need.

When it’s time to anchor, go to a spot that has plenty of depth also.

Glad I'm not the only to have done this! The string bit is certainly an idea, though it would have quite the ways to go to make sure we are safe. Sticking to the channel it is

[Notyetsinking]

Originally Posted by SailingHarmonie

People sailed boats for thousands of years without sonar. You can too.

I have no idea why you would want "millimeter level accuracy" on your GPS or how that helps, but the only thing I would have would be a lead weight on a string to measure depths at the spot I was going to anchor. Otherwise, sail carefully, and be doubly careful at high tide. The Chesapeake is almost all very soft mud so even if you screw up, its not a big deal.

Suppose you're right with that. Though they also sailed without charts and crashed a bit more than I would like . As to the millimeter comment, it's a piece of a project I've been working on where that accuracy is important to other components and calculations for the system.

Good points on the tides, though I assume you mean low tide? I will certainly not be trying to "time" narrow inlets without actually knowing what the current depths are. But as they say " if you haven't been aground, you haven't left the dock"

[Notyetsinking]

Originally Posted by George_SD

You can put in a an in-hull sounder connected to a portable fishfinder like the Garmin Striker 4. It will give you depth and comes with everything you need. Costs $120 and can use it for fishing on your dinghy as well It will actually mark fish, not just show depth. One requirement - non-cored location.

I use a CHIRP fishing transducer set in the bilge with a dollop of wax in front of the keel, it's connected to my Axiom chart plotter - works great and reads to about 400ft. It's a cheap low-power transducer that came with the unit and I can put a more powerful one if i want to, but.....why bother?

Good idea. The boat is cored, though I don't know if that is just above the waterline or the entire boat. So maybe that would work? For $120, might be worth a shot! Certainly goes to show there is quite a heavy sailing tax....a 20 year old B&G transducer is more expensive than that!

[JPA Cate]

Well, we have never sailed without a depth sounder. Some friends of ours circumnavigated with just a VHF (bridge openings, communication with others) and a depth sounder. The depths help locate you on the chart. We have taken lead lines to sound prospective berth's depths, too. (our first Insatiable ran aground with the bow about 8 ft. from the dock.)

I understand Labor Day Weekend is coming up and you want to take advantage of it, so give it a go and see how you do. If you touch at very slow speeds*, not much will happen where it is only mud anyway: stone or coral reefs are a different proposition. If you run aground at normal speeds, someone may get hurt, from a fall, when you stop fast. As chotu suggested, don't go near the skinny bits.

* I would say less than 2 knots. Most of our serious exploration of waters you cannot see into has been around 1 kn. to 1.25. And we used a forward looking depth sounder to keep us off hidden rocks, reefs, etc.

Have a good holiday weekend, just be really attentive to depths; and known ranges in anchorages.

Don't know your draft, but people can use marked sticks for sounding, even their boathooks; or make up their own lead lines. You prefer to stay off the putty.

Ann

[Simi 60]

Originally Posted by Chotu

You are definitely all set. Just stay in the deep water as shown by your chart plotter.
.

But charts and chart plotters are not necessarily accurate.

We regularly take our vessel into areas shown as land and we draw 7.5ft
And we regularly walk on land in areas shown as water.

[Chotu]

Originally Posted by Simi 60

But charts and chart plotters are not necessarily accurate.

We regularly take our vessel into areas shown as land and we draw 7.5ft
And we regularly walk on land in areas shown as water.

That doesn’t really happen in the continental United States. I think our charts are pretty good over here.

The only time you are showing up on land or in the wrong spot is when there is a massive GPS error which is really really infrequent and lasts only a few seconds. But it’s pretty obvious.

Plus, everyone should have a charting app on their phone so they can double check anything that’s looking odd. I use iNavX to look at raster charts and compare while my main chart plotter is the Raymarine axiom 9.

This person is asking about spending some time in the Chesapeake. Not navigating an atoll in the South Pacific. Lol. The chart plotter will be fine for keeping them in the channel there as will their eyes.

They can creep into an anchorage too (like Ann was suggesting), just using slow speed and the lead line.

I use my lead line all the time.

[Jammer]

Well


Throughout history there has always been some means of measuring depth. In Samuel Clemens' book "Life on the Mississippi" (1883) he wrote of steamboats having two leadsmen, one to port and one to starboard, casting lead lines and shouting out depths.


I remember the first time one of my family members got an electronic depth sounder. It was about 1975 or so, and my cousin, then an avid fisherman and now a semiprofessional fishing guide, received it as a gift from his father. It ran for a day on two 6v square lantern batteries and had this motorized wheel with a neon tube that would flash when the pulse came back, and a sunshade so you could see it.


We are blessed that in this modern age depth instruments are cheap and convenient by comparison. I have a Vexilar Sonarphone depth instrument that I use on my canoes via bluetooth to a smartphone (vexilar.com). The transducer attaches with a suction cup. I have a Hawkeye DepthTrax ($99 at defender) on my 14' aluminum dinghy, with the transducer glued to the inside of the hull. They both work, and so there are these among other options if whatever other systems you have aboard are behaving badly.


I spent a good deal of time on boats and a fair amount at the helm before electronic depth instruments were ubiquitous. It can be done. Charts (when available), memory, local knowledge, all part of being a boater in those days. I remember running aground on a friend's brand-new boat that drew 4" more than his last boat in a bay that he previously thought safe.


So, my advice, in this modern age, get something -- anything -- and install it to shoot through the hull or attach it to the transom or whatever. It's the most important piece of electronics on the boat. Radar is next, then VHF, then GPS, by my reckoning anyway.

[JPA Cate]

The only thing wrong with that is that they have to keep their eyes mostly on the chart plotter, which will take away from the quality of the watch they could otherwise be keeping. To me it is a serious flaw in the plan, but I still think that as long as the bottom is mainly gooey mud, and they stay away from the shallower bits, they'll probably be okay.

If they have kept their records of places safe to go stored in their GPS, they should be able to stay out of much trouble.

We hope they will.

Ann

[SailingHarmonie]

Originally Posted by Notyetsinking

Good points on the tides, though I assume you mean low tide? I will certainly not be trying to "time" narrow inlets without actually knowing what the current depths are. But as they say " if you haven't been aground, you haven't left the dock"

No, I meant exactly what I said: "Be careful at HIGH tide. "

If you run aground at low tide you wait an hour and you're off. If you run aground at high tide you wait a month before you get off (if then).

If that wasn't obvious to you, you are right. You need to stick with technology to solve your problem.

[dfelsent]

Originally Posted by Chotu

That doesn’t really happen in the continental United States. I think our charts are pretty good over here.

The only time you are showing up on land or in the wrong spot is when there is a massive GPS error which is really really infrequent and lasts only a few seconds. But it’s pretty obvious.

Plus, everyone should have a charting app on their phone so they can double check anything that’s looking odd. I use iNavX to look at raster charts and compare while my main chart plotter is the Raymarine axiom 9.

This person is asking about spending some time in the Chesapeake. Not navigating an atoll in the South Pacific. Lol. The chart plotter will be fine for keeping them in the channel there as will their eyes.

They can creep into an anchorage too (like Ann was suggesting), just using slow speed and the lead line.

I use my lead line all the time.

I beg to differ a bit about chart accuracy. I’ve been in Maine, in 20 feet of water in a narrow channel, with the chart plotter showing me 50 feet ashore. On rock.

I’ve been in massachusetts in 8 feet of water where the chart has shown 20 feet. Three days ago.

One was an old survey. One was recent shoaling.

But generally Chotu is correct we have excellent surveys and they are well aligned with the gps coordinates.

When I was a kid a depth sounder was a luxury. In the 1960s. We had and used a lead line gunkholing, or my brother and I were sent ahead in the dinghy to sound. We were often in poorly or inaccurately charted waters.

I second the charting app and the lead line v

I’ve used a fishing line with a sinker. That works too. A string with a shackle. Anything. It’s really obvious when you sound bottom try it before you go.

Be careful, and when you run aground do it in mud or sand and slowly.

It will be ok if you take proper care.

[ggray]

There are places on the Chesapeake Bay where the chartplotter is not accurate, or perhaps I should say, not current.

I could have run aground in "30 feet of water" just off the southeast tip of Tangier Island if I had blindly followed the chartplotter. Just found this note at this spot on Active Captain: "Reported LNM Week 45/2017: Shoaling to 5-6 feet MLW has been found in the vicinity of Tangier Sound Light in approximate position 37 47 06.4N, 75 58 23.2W along the 36 foot depth contour."

The bottom there is very deep and comes up very quickly. The contour lines almost run together.

You could cruise the Chesapeake w/o a depth sounder, but you would be more limited. And rather than a weighted string, I'd use a pole.