Anchoring too close to other boats?

[CatNewBee]

I understand this in crowded anchorages, but if you are the only boat on a 5km beach, and the next skipper snuggles 50m next to you, and you have plenty of chain out not straight ahead but next to his anchor spot, afriendly remainder is sometimes inevitable.

[Dockhead]

Originally Posted by AJ-SeaChange

. . . The nice lady who checked us out suggested that we re-anchor as our chain was not laid out straight. . . .

???...

[BobMc]

The "correct" amount of scope is never a function of the number of boats in an anchorage or whether it is crowded. It's pure and simple a matter of how much scope is necessary to hold under the anticipated conditions. If it's too crowded for the proper amount of scope, move to a different location. 10:1 overnight - probably a good idea; any less, taking a chance unless you are absolutely assured that the forecast is for minimal wind and you have an excellent holding bottom.

Originally Posted by Dockhead

This is why it's bad to have excessive chain out, and also why it is good to know what others are doing.


7:1, 8:1, 10:1 in crowded anchorages is just wrong. 5:1 is plenty; 6:1 if others are doing that, but a boat on 8:1 anchored close to boat on 5:1 or 4:1 is asking for trouble, at least in tidal waters.

[Cadence]

Originally Posted by Dockhead

This is why it's bad to have excessive chain out, and also why it is good to know what others are doing.


7:1, 8:1, 10:1 in crowded anchorages is just wrong. 5:1 is plenty; 6:1 if others are doing that, but a boat on 8:1 anchored close to boat on 5:1 or 4:1 is asking for trouble, at least in tidal waters.

That is the truth. When the tide swings you're liable to be on top of one another, with twice the scope Another consideration is how much effect tide and wind has on different boats. You could end up at 90 degrees to someone else eg. a tri with 2' draft and a mono with 6 with a tide swing and a stiff wind, or one may not swing at all. They may not swing in the same direction. Sleep with one eye open.

[georgeg305]

A few comments:
1. We used to cruise a bit. Never serious for long periods, however, first of all I used a float on my anchor with just enough scope to mark where the anchor is. Late arrivals can then judge how much scope you have out in case the wind starts moving around. Lots of troubles when large changes of wind direction and closely anchored boats with different scopes.
2. Chain on sand provides lots of drag. Even full reverse after anchor is out may not actually set the anchor. I.E. just the drag on the chain may be enough to hold the boat without engaging the flukes. ( Even Full power in reverse doe NOT provide a lot of force ) 3. Danforths do NOT set as well as a Bruce. A Bruce or the clone will set immediately if proper load applied. I found a Danforth in the BVI's with a bent fluke. That sucker would NOT set but roll out as soon as load applied

[PeterNearhos]

Sydney Harbour. Four boats rafted up drifted so close they were able to hand across to us a couple of bowls of very fine seafood chowder as recompense. I guess some anchorages are just like that.

[JDGreenlee]

30' Darwin tides require extra scope. Hiva Oa requires anchors fore and aft. Zulu Yacht Club is a tight fit where 20' is about right. But don't anchor within a half mile of me when I'm going native.

[Mahayana]

Originally Posted by Sparx

I am leaving New England where 20 feet between boats is sometimes fine and normal in crowded anchorages. I always try to keep my scope similar to the adjacent boats in these situations.

150 feet of chain in 18 ft of water is at least 50 feet more than I would have used. Shortening up would solve the problem.

+1. 100’ is more than enough in a crowded anchorage.

[StumpLifter]

20'! Hey, that's plenty of room for your inflatable dingy. Seems like a lot of chain for that size boat though.

[Tillsbury]

[QUOTE=wingssail;2965859]

Originally Posted by Andina Marie

We were in a crowded anchorage in Elizabeth Harbor.
The sound of a heavy anchor chain rattling got our attention.
A 75 ft yacht had grabbed a spot right in the middle.
One of the others near it shouted "You're a little close there aren't you?"
To which they replied "Oh its OK, we're made of steel."[/QUOTE

Shouting at someone whom you think is too close is poor form, I'd say, as is expecting that your territorial instincts allows you to decide what is a safe place for another to anchor.

Maybe it's Just me, but I don't assert my rights in that way.

If I think someone has anchored too close I will launch my dingy and go over to his vessel. In a friendly way I'll introduce myself and then ask him if he thinks it's OK where he's as, because I see some risk of hitting(or some such thing).

Sometimes the guy will agree and say, "Ok I'll move."

Sometimes they will say, "No, I think we'll be fine."

I don't argue. If I feel strongly, I'll move.

No hard feelings.

When we do eventually have mandatory skipper licensing, can we have this as the first section please?

[Dockhead]

[QUOTE=Tillsbury;2966379]

Originally Posted by wingssail

When we do eventually have mandatory skipper licensing, can we have this as the first section please?

Indeed!


Andina Marie describes the right way to do it, and the right attitude!



In fact, you can even skip the discussion with the other skipper if there is a reasonable place to move to. Generally takes less time to just move, if you don't like it.



Or just have another cocktail, knowing that in reasonable weather, boats hardly ever swing into each other, and even if they do, it hardly ever causes any damage.


This hardly ever comes up in my life these days, as I sail now in places where crowded anchorages don't exist. But here's a story from the past:


http://www.cruisersforum.com/forums/...ain-86277.html

[Simi 60]

Pulled up anchor this afternoon and moved because there were 8 boats in the anchorage (we have seen 30 here before but consider it full with 8) and the nearest was 100+ ft away, and then on the gust we sailed in different directions and we were 20 ft away.
Another boat pulled up anchor and left freeing up a spot that got around 300ft between us and the nearest.
They'll all be buggering off back to work tomorrow and we'll have it all to ourselves.

Mid week in this part of the world is magic.
We have multiple anchorages, often zero boats seen , clean clear water but we can still see high rise buildings of the states capital city on the horizon.

[Dockhead]

Originally Posted by BobMc

The "correct" amount of scope is never a function of the number of boats in an anchorage or whether it is crowded. It's pure and simple a matter of how much scope is necessary to hold under the anticipated conditions. If it's too crowded for the proper amount of scope, move to a different location. 10:1 overnight - probably a good idea; any less, taking a chance unless you are absolutely assured that the forecast is for minimal wind and you have an excellent holding bottom.

Well, I beg to disagree. This is a statement of the "fetish for scope" which we see from time to time, and it is an error which leads to different other errors in anchoring.



10:1 is NEVER a good idea, unless you're about to go through a hurricane and the last kilogram of chain out could conceivably make some slight difference. Or if you have a terrible anchor, or an undersized anchor, but in all of those cases, using excessive scope is the wrong solution.


The crucial fact is that increasing scope gives steeply diminishing returns in holding power beyond 5:1:






Scope & Rode


If your anchor won't hold at 5:1, then it is not going to hold at 10:1, and you need be thinking about other factors.


And that graph is an old one, based on old type anchors. As Steve Dashew says:


"Now let’s consider scope. Old time anchors require five-to-one scope to attain good holding. But the modern types can get by with less. The Manson, Rocna and Fortress showed little difference between three and five-to-one scope. The Manson hit the max test load of 5000 pounds at both three and five-to-one."

https://setsail.com/anchoring-system...true-approach/


So, with a good modern anchor, you get little increased holding power beyond 3:1 scope. Yet, increasing scope to get a non-existent advantage, increases the area of your swinging circle GEOMETRICALLY -- double the scope, and increase the area of your swinging circle 4x. This is extremely bad form in a crowded anchorage, typical sign of bad seamanship and poor anchoring knowledge. If you have 40 meters of chain out, pulling in just 10 meters, HALVES the area of your swinging circle.

Dashew uses a very large and very good anchor, and TYPICALLY anchors at 2.5:1 or less. His theory is that it is better to have no more chain on the bottom than absolutely necessary, because it creates a risk of jamming it on a rocky bottom. I don't go that far, myself -- if there is plenty of room and no other boats around, I will let out more chain, but I don't delude myself into thinking that any scope beyond about 5:1 makes any material difference in holding power.



Putting out 10:1 or even 8:1 in a crowded anchorage is bad seamanship, pure and simple.

[CatNewBee]

Tried it, 10m depth, 40m scope 4:1, thunderstorm 40kn wind, anchor dragged in sand slowly due to lift on the chain, 5m depth, 35m rode 7:1 thunderstorm, 45kn, sand, anchor holds while others drag. Its about the angle of the attack, not only the length of chain, so a higher ratio is better. In calm weather chain alone is sufficient. (40ft heavy Lagoon cat with 85lb Mantus and a lot of windage)

[Dockhead]

A modern anchor, properly set, properly sized, in a reasonable bottom, should hold at 4:1. I went through a full gale on 2,5:1 last summer in Greenland.

Originally Posted by CatNewBee

Tried it, 10m depth, 40m scope 4:1, thunderstorm 40kn wind, anchor dragged in sand slowly due to lift on the chain, 5m depth, 35m rode 7:1 thunderstorm, 45kn, sand, anchor holds while others drag. Its about the angle of the attack, not only the length of chain, so a higher ratio is better. In calm weather chain alone is sufficient. (40ft heavy Lagoon cat with 85lb Mantus and a lot of windage)