Dumb Anchoring Question

[Liam Wald]

Doesn't it seem like a bad idea to anchor in 5 feet of water and then back into deep water? What if the wind shifts? Do you end up on the beach?
I would be more comfortable anchoring in deep water and then backing toward the beach being sure that there will still be water under me at the lowest possible tide.

[Vasco]

Originally Posted by Liam Wald

Doesn't it seem like a bad idea to anchor in 5 feet of water and then back into deep water? What if the wind shifts? Do you end up on the beach?
I would be more comfortable anchoring in deep water and then backing toward the beach being sure that there will still be water under me at the lowest possible tide.

Depends on how far away the beach is. There are quite a few spots in the US East Coast and Bahamas where you can drop your hook on a bar or shelf that deepens fast as you fall back. For example I have anchored many times in Ft. George River, FL. where the hook goes in at eight feet in the middle of the river and as you fall back towards the riverbank the depth is over twenty feet due to scouring. The deepest water here is very close to the river bank.

As for "anchoring in deep water and then backing towards the beach", in real life anchoring it doesn't work that way. You back the way the wind or current takes you.

[GordMay]

Originally Posted by Vasco

... As for "anchoring in deep water and then backing towards the beach", in real life anchoring it doesn't work that way. You back the way the wind or current takes you.

Exactly. You anchor according to the significant forces (wind, current, waves, or some vector of them).
I'd calculate my scope, depending upon the deepest depth within my entire swinging circle; always trying to avoid very steep drop-off slopes.

[ahnutts!]

Originally Posted by Vasco

As for "anchoring in deep water and then backing towards the beach", in real life anchoring it doesn't work that way. You back the way the wind or current takes you.

Agreed, I like to back onto my anchor in the same direction other boats in the anchorage are pointing.

I consider tides to be one of the most important factors when anchoring. Put out sufficient scope for high water and be sure you'll have water under your keel at low water. If you lose 10 feet at low tide your swing radius gets much bigger and the beach can get a lot closer.

[thinwater]

Originally Posted by Waterway Guide

I'd also try to figure out if there's a ledge of some sort which could be pretty dangerous...

Which sort of points toward the whole shallow water anchoring thing. If the wind clocks around and waves or even very large wakes come in, they will be breaking in the anchorage. Folks lose boats that way:
Sail Delmarva: How Quickly Things Can Change...

It is very nice to be able to anchor shallow, but it should ONLY be done in very protected locations or for lunch stops.

[sailorboy1]

In some of the anchorages I normally go to in the area I'm always amazed at how many come in after me, sneak in further in the cove to get to the 10' water, just to be be in a bad position if there is a problem later. I prefer to be out a little more and drop anchor in the 20-30' water knowing if I were to drag I have a chance to do something before going onto shore first. Got 300' of rode, doesn't matter to me if only 100' of it or 200' of it is out (windlass doesn't seem to care).

[SteveT]

On commercial ships the traditional 'rule of thumb' is 3:1 scope which when you are anchoring in 250 feet of water or more means you are getting close to nearly all your chain anyway. On a yacht I personally like to use 5:1 assuming there is swinging room and if not I'd look at a stern anchor as well or going somewhere else altogether. Something no one has mentioned is rise of tide - my cruising area has tides which easily top 30 feet and if you anchor at low water in shallow (10-20 feet) water you really need to be thinking of the tide as your 10 feet easily becomes 40 and your scope got a whole lot less!

[foggysail]

Originally Posted by 44'cruisingcat

In that circumstance it would pay to let out additional scope though, because if you drag a little, your anchor will move into deeper water, reducing the effective scope.

And of course, because you're anchoring near a beach you would limit adding scope that could allow your boat to sit pleasantly on the beach.

[jackdale]

If you are anchoring on a sloped bottom, you should use a stern line to prevent the boat from swinging and pulling out the anchor.

[Hillbillylad]

Thanks all for your insights. It seems that situational awareness is the main criteria and an understanding of the required angles. I have a feeling a lot of the boats that suffer dragging etc are confident they have followed the 5 to 1 or whatever formula but not took into account other factors.
for myself, it is an area I worry about and will study deeper and practice often.

[markpierce]

Now, how many feet of chain have I lowered? Got to get the chain marked.



One needs to account for sea-level changes too. Got tides?

[Capt.Fred]

In Yelapa, Bay of Banderas, I put my stern anchor in the water near the beach and it was stolen at 0400. I felt the change in the boat's motion while asleep. I jumped up, hit the engine and swung away from the looming rocks. I headed out to sea and retrieved my now freely hanging bow anchor. The bottom drops off to hundreds of fathoms very quickly. I returned to the beach as dawn broke, and the Chief of Police was fishing at my anchor spot. I started to report to the Chief and decided that might be a mistake and dropped it.
My anchorage was located right off the beach where they sell that famous tequila called "Ricea". I bought a gallon the day before. You must supply your own bottles. Then, I was ready to continuing on down the Coast with my darling shipmate and a gallon of that dynamite Ricea. To make this a bit interesting. I'll tell ya-how to drink Ricea. Keep a grasp on the bottle because, after one shot you go blind. The only antidote is another slug.

[Vasco]

I do not like stern anchors. I'm always afraid that when conditions change, and they usually do, I'll be stuck beam on to the seas. I have taken stern lines ashore when at anchor in St. Vincent and in a little secret spot in BVI but I still feel uncomfortable. Just like to swing on the hook.

[Ex-Calif]

I am always amazed by guys that "drive" into an anchorage and basically fling the hook.

I look at the chart to get an idea then cruise back and forth around the area, mentally mapping the bottom. I like flat, as shallow as safe but want to know where deep water is and have it close if I have to get out of there in the middle of the night in the dark.

It's all about options. The bad scenario is a big onshore wind with dragging or the threat of dragging. Of course there is deep water to windward somewhere but what if the engine doesn't start and I have to sail out? Is better water to north or south? Options are closing down. Better to know as much as possible in advance before standing in underpants at 3 in the morning in the rain and wind trying to find charts, get sails up, haul anchors etc. etc. etc.

What if I anchored stern to as well. Can I unset both anchors under sail alone in the dark wind and rain? Do I have a suitable float handy to float the rode and come back for one or both anchors later?

Always ask yourself if you have maximized your options...

Also have you watched boats swing in a mooring field? If you get wind with current most boats "head" downwind and if aided by current tend to drive straight across the mooring point. When it reaches the end of the rode is it going to "flip" the anchor or jerk around?

Some boats "sail" upwind on windage alone. We had finished a race. Wee hooked on the mooring ball and cracked a couple of beers. Soon the boat was wrapped on the mooring rode abeqm the current and wind. We manhandled the boat loose and went back to beers. The boat did it again and this time we had a hell of a time unwrapping the keel until I pushed the centrally lashed tiller over. The boat steered a 360 back around the rode. The boat was sailing upwind against the current. I lashed 10* steering angle in and we enjoyed our beerrs in peace.

[jackdale]

I also do not like stern anchors. When I stern tie I use a long line to a rock, tree or ring. Ideally I can bring the line back to the boat so that I can release and retrieve the line. If need be (not yet) I can simply cast off the stern line.

When stern tied, I also set my anchor just as I would if swinging: 1500 rpm in reverse while checking the anchor rode for vibration and checking transits ashore. I will not stern-tie if I have a strong wind abeam.

Ex-Calif

Why do you use a long pennant? I know some mooring balls come with pennants, which I do not trust. I build my own bridle through the ring, using 2 bridles if I can concerned about chafe.