Shallow Water Anchoring

[boatman61]

Never anchor that shallow in an onshore wind.... thats a 4 - 5 metre job... minimum.

[zeehag]

onshore wind can easily make surfline conditions----no fun.

[sailorboy1]

I did say - calm conditions

[chala]

Originally Posted by Arch Stanton

with proper rode along a sloped bottom as the tide goes out can easily change your clearance from over 30' to less than 5' in a couple hours.

Curious, must be because we live the other side of the world but here as the tide (7 m +) goes out, the boat on 40 meter chain, move into deeper water, 0.3 m clearance is OK because the water does not stay low for very long.

[IdoraKeeper]

I am with boatman on this. I will try to plan for 15' at low tide. That would include the most shallow spot anywhere in the radius of my rode. I also like enough room to sail off the hook in a pinch.

Todd

[capngeo]

Luckily around here the tide is about 2' unless full moon or storm. If I have a foot under the keel I'm a happy camper at low tide

[foggysail]

It all depends on the bottom... and the type of boat. My current power boat requires care or I might damage the props. But my old Hunter 30 was a different boat. I anchored for years in soft mud with the keel buried at least a foot into it at low tide.

I also enjoyed being ALONE! Nobody anchoring near me and when others asked what the boat's draw was, I told them it had a centerboard. It was really great because the harbor where I was anchoring was always full during weekends. AHHhhh, those good old days!

Foggy

[Bruce Bevan]

So what if you unknowingly shallow anchor in what you think to be a protected anchorage, but it isn't? I did!

I used to regularly anchor with five or six feet under the keel.
After all, the keel was cast iron so nothing would hurt it if it did touch. It would also allow us to sneak inside the larger boats and find a good spot near the beach. Easier to ferry the kids ashore.

So the wake-up came one night at the Tumbo Island marine park located at the south end of Saturna Island in the PNW. The channel has mooring buoys but we anchored because we don't like the banging that occurs when the currents turn in the middle of the night. The westerly wind picked up in the night against a strong ebb that generated huge standing waves. So rough we could not raise anchor and had to ride it out,sick kids and all. We had sand covering the foredeck as the wave trough sent us very close to the bottom. If we had hit the bottom it could have caused a capsize. A little more cautious from now on.

BB

[beetle]

On an 8' draft, shallowest I like to anchor in is 20' of water at low tide - I like having water beneath the keel.

And it's problematic having an 8' draft in San Francisco bay, as suddenly you don't fit into many marinas, and often one anchors a fair ways out to keep the depth going. Therefore I like my dinghy and outboard motor!

- rob/beetle

[four winds]

It certainly must depend on location, I suppose. .... Well, wait, low water is low water everywhere. How much you have to spare is the skipper's call by choosing where to drop the hook. I guess the less room to spare at low water, the more accurate the evaluation of tidal and bottom conditions must be. I'm here to learn and everyday a discover a new subject to investigate.

At sunset today I motored back into the marina where my slip has 6 feet at low tide, for my 4.5 ft. draft. High tide is +2-3 ft.

Anchored out in the bay the last three nights with the same numbers. Wind and chop and swinging 180. Now back in the slip it feels like the boat isn't moving.

Don't know when I'll be cruising where the tidal range is greater, but I got some learnin' to do about this subject. Until a few months ago, I had no idea the tidal range could be 30 feet or more in other locations.

[Uncle Buck]

In calm conditions, with a mud bottom (and I am confident that the conditions will not change to put me at risk), with a 7'6" draft and I commonly anchor with less than one foot under me at low (low) tide. You have no other choice here unless you want to anchor WAY out (or miss the good spots altogether) in some places. Steel boat, so far so good (knock on wood, big minus tide tonight, on the hook now!). I check depth the old fashioned way - lead line. I can see what the bottom is, and there is no room for some kind of goofy electronic error. I also try and sound as I swing around to find out if the bottom is unevenly contoured.

Onshore conditions with the possibility of wind/surf? I'll be the furthest one out, and I dinghy the old fashioned way too - rowing....

[markpierce]

Originally Posted by beetle

On an 8' draft, shallowest I like to anchor in is 20' of water at low tide - I like having water beneath the keel.

And it's problematic having an 8' draft in San Francisco bay, as suddenly you don't fit into many marinas, and often one anchors a fair ways out to keep the depth going. Therefore I like my dinghy and outboard motor!

- rob/beetle

My goodness. With 8-foot draft, a majority of the surface area of the various bays of the SF "Bay Area" is too shallow at MLLW. Keep to the shipping channels!

[beetle]

Originally Posted by markpierce

My goodness. With 8-foot draft, a majority of the surface area of the various bays of the SF "Bay Area" is too shallow at MLLW. Keep to the shipping channels!

Too right - I've awakened in the mud in more than a few marinas, and don't fit into Clipper Cove to boot. On the other hand, Beetle goes to weather like a banshee!

My favorite local places are Drakes Bay and Half Moon Bay. Up at Drakes the anchorage starts at 80' and it's a stable even slope to the surfline so it's dial-a-depth by just motoring in until your happy and drop the hook. At Half Moon I avoid the area by the outer-harbor pier, elsewise it's good. It's nice to be in the eastern Pacific and have some depth. Thin water no good!

- rob/beetle

[Pyrate]

Personally, I'd go conservative. There's always the chance of some rock jutting out of the sand, unexpected waves or wakes, or a low pressure system far enough away to not affect the local weather, but affect the tides. And, being in Alaska, where today's tide went from -2.85' to 18.14', I just plan on anchoring in as deep water as I can while keeping a 5:1 ratio for the scope. Of course, we have few if any crowded anchorages up here.

Pyrate

[sailorboy1]

So far I'm surprised at how conserative everyone seems to be. I anchor lots of times in water that is going to be less than 2' clearance at low tide. I've even been to moorings that are at best 8' at low tide.

I was expecting people to say that they would anchor in water less than their draft at low tide and soft bottom sometimes.