Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 23-09-2012, 23:18   #1
Registered User
 
stevensuf's Avatar

Join Date: Dec 2010
Location: Algarve, Portugal
Boat: Gib sea 43
Posts: 1,009
Images: 10
Every boat dragged bar one!

And a pity it was not me, but hey I was the last one to drag

Now my question is, are you less likely to drag say anchored in 15m with 45m of chain out, than in 5m with 15m of chain out?

I thought i was ok sitting in 10m with 45m of chain out, I would like to have put more out, but one of those silly superyachts was parked behind me.

The forecast of 25-30kn was a little bit conservative, 25-30knn sustained with gusts of 45kn.

I am now not dragging , sitting in 8m with 65m of chain out. (wish i'd done this in the first place!)

Lesson learned..
__________________
https://nicnsteve.blogspot.com/

If the pen is mightier than the sword, then my keyboard must be a nuclear missile!
stevensuf is offline   Reply With Quote
Old 24-09-2012, 00:39   #2
Registered User
 
rebel heart's Avatar

Join Date: Oct 2005
Posts: 6,190
Images: 3
Re: Every boat dragged bar one!

Big drag or little drag? I had a delta that would move maybe 10' every night when gusts came through. It never broke loose but would just keep wiggling around. Kind of weird.
rebel heart is offline   Reply With Quote
Old 24-09-2012, 01:05   #3
Moderator
 
noelex 77's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Boat: Bestevaer.
Posts: 12,577
Re: Every boat dragged bar one!

An anchors holding is proportional to tha scope, with everything equal the same scope in deeper water is very slightly better as the chain has some catenary although this disappears in stronger wind, so it is only a minor factor.

It's important to add the bow roller distance when calculating scope so assuming this is 1.5m the scope is
45/15+1.5=2.7:1
15/5+1.5=2.3:1

Neither scope is adequate and in practice a difference in bottom conditions would be far more significant than the small difference in scope., but in the example you give assuming these factors can be ignored the deeper anchorage is more secure.
In practice it is easier in shallower anchorages to get a better scope ratio even a few extra meters of chain makes a big difference. Shallower anchorages are also usully more protected from the wind and wave action and you are less likely to hit by other boats dragging. So in the real world the shallower anchorage is generally superior.

In 10m with 45m of chain out your scope ratio was 45/10+1.5=3.9:1.

This is lower than would normally be used in the wind conditions you describe. If you could have let out more it would have substantially increased your holding power, which goes up quite signifficantly especially at the lower ratios 7:1 would have probably doubled your holding capacity and even a small increase to 5:1 would have been a help.

If you don't want to move often talking to another skipper helps. It's not in the superyachts interest that you drag as you may hit them. If you both let out 20-30m more scope the relative position of the yachts would be unchanged and you both would have been more secure.
noelex 77 is online now   Reply With Quote
Old 24-09-2012, 03:04   #4
Registered User
 
stevensuf's Avatar

Join Date: Dec 2010
Location: Algarve, Portugal
Boat: Gib sea 43
Posts: 1,009
Images: 10
Re: Every boat dragged bar one!

Big drag, several boats were half way out to sea, despite people shinning torches blowing fog horns etc, before the skippers woke up, at least the smart phone anchor alarm i keep beside me when i sleep works well.

There were around 20 odd boats in the anchorage luckily none were washed on the rocks to the very far side, though some narrowly missed them and only 2 boats got tangled but were quickly separated.

Here in the med 3 to 1 is often the best you can manage in many of the anchorages and is probably more than half the boats have put out.
__________________
https://nicnsteve.blogspot.com/

If the pen is mightier than the sword, then my keyboard must be a nuclear missile!
stevensuf is offline   Reply With Quote
Old 24-09-2012, 05:03   #5
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 15,396
Re: Every boat dragged bar one!

Quote:
Originally Posted by stevensuf View Post
Here in the med 3 to 1 is often the best you can manage in many of the anchorages and is probably more than half the boats have put out.
Really? Now that's scary. I don't think I could sleep anchored with only 3-1 scope.
__________________
The water is always bluer on the other side of the ocean.
Sometimes it's necessary to state the obvious for the benefit of the oblivious.
Rust is the poor man's Loctite.
skipmac is offline   Reply With Quote
Old 24-09-2012, 05:44   #6
cruiser

Join Date: Aug 2011
Location: Tampa Bay area
Boat: Hunter 31'
Posts: 5,731
Re: Every boat dragged bar one!

Quote:
Originally Posted by rebel heart View Post
Big drag or little drag? I had a delta that would move maybe 10' every night when gusts came through. It never broke loose but would just keep wiggling around. Kind of weird.

An anchor that will reset when there's enough room to survive the drag won't be a big problem. I haven't done a lot of anchoring out, and my anchor was NOT big enough. The anchor dragged -- and reset -- I don't know how many times, but in a big squall it dragged 500 ft. I know because I had marked the anchor spot with my chart plotter. Fortunately no one was around me, but I knew the anchor wasn't great Not going to go into details about anchor type, should have been enough chain and enough scope, so I'm replacing the anchor.

I've seen all the anchors drag but none of the well-made moorings made in big strong squalls.

I don't have years of experience on this. It's just what happened to me the one time I was anchored out in a very strong squall. Don't really want to experience that twice.
Rakuflames is offline   Reply With Quote
Old 24-09-2012, 05:48   #7
cruiser

Join Date: Aug 2011
Location: Tampa Bay area
Boat: Hunter 31'
Posts: 5,731
Re: Every boat dragged bar one!

Quote:
Originally Posted by Rakuflames View Post
An anchor that will reset when there's enough room to survive the drag won't be a big problem. I haven't done a lot of anchoring out, and my anchor was NOT big enough. The anchor dragged -- and reset -- I don't know how many times, but in a big squall it dragged 500 ft. I know because I had marked the anchor spot with my chart plotter. Fortunately no one was around me, but I knew the anchor wasn't great Not going to go into details about anchor type, should have been enough chain and enough scope, so I'm replacing the anchor.

I've seen all the anchors drag but none of the well-made moorings made in big strong squalls.

I don't have years of experience on this. It's just what happened to me the one time I was anchored out in a very strong squall. Don't really want to experience that twice.
PS I had the length of my boat in stout new chain and an 8:1 rode when I dragged, which is why I'm so suspicious of the anchor. It wasn't a SEVERE squall. Not the worst we've seen around here at all.
Rakuflames is offline   Reply With Quote
Old 24-09-2012, 06:08   #8
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Posts: 4,033
Re: Every boat dragged bar one!

Quote:
Originally Posted by stevensuf View Post
Here in the med 3 to 1 is often the best you can manage in many of the anchorages and is probably more than half the boats have put out.
Agreed, and also in other crowded places also (like English harbor), 3:1 and less is more common than 'the books' suggest. It is one of the reason we have a way bigger main anchor than normally specified for our boat . . . to give us greater confidence when short scoped.

An alternative to a jumbo main anchor is, when you are forced to short scope, to put out tandem anchors (one shackled in front of the other with a short piece of chain). Particularly if you have two bow rollers there are various set-ups (for pick-up lines) which make tandems relatively painless to recover. But you really should do that ahead of time, as in the middle of a blow is not the best moment to be sorting it out.

Dragging, especially in the dark, is certainty no fun. In your situation . . .
I might have tried to talk to the super yacht and have him agree to let out extra rode so that you could. But he may have then been constrained by someone behind him.
I would have considered motoring up and dropping a second anchor.
I would have considered simply leaving the motor on in light forward and steering into the wind to take strain off the rode.
And of course there is always the option of pulling up the anchor and going to sea, but that can sometimes be difficult in the dark in a crowded anchorage.
estarzinger is offline   Reply With Quote
Old 24-09-2012, 06:09   #9
Registered User
 
stevensuf's Avatar

Join Date: Dec 2010
Location: Algarve, Portugal
Boat: Gib sea 43
Posts: 1,009
Images: 10
Re: Every boat dragged bar one!

I find 3 to 1 with the anchor i have is good up to 25kn, 4 to 1 so far has been fine to 35kn , which was 10kn more than predicted, i did see the wind gauge hit 45 in the gusts, the prob was when i dragged i went from 10m depth to 13m, i let out more chain, then dragged to 15m and i had all 65m of chain out, it was not enough for that depth and wind speed.
__________________
https://nicnsteve.blogspot.com/

If the pen is mightier than the sword, then my keyboard must be a nuclear missile!
stevensuf is offline   Reply With Quote
Old 24-09-2012, 06:19   #10
Registered User
 
stevensuf's Avatar

Join Date: Dec 2010
Location: Algarve, Portugal
Boat: Gib sea 43
Posts: 1,009
Images: 10
Re: Every boat dragged bar one!

Luckily, unlike most of the others, i had not dragged out to sea, so i pulled the anchor in, motored nice n close to 8m depth and dropped all 65m of chain, never budged an inch after that, if only i could have done that ion the first place, nb the next morning all boat were very well spaced out with pretty much all their chain out. now if only people could all anchor like that in the first place instead of trying to get into places where there are no places, just for the sake of being close to the beach/dinghy dock.
__________________
https://nicnsteve.blogspot.com/

If the pen is mightier than the sword, then my keyboard must be a nuclear missile!
stevensuf is offline   Reply With Quote
Old 24-09-2012, 14:40   #11
Marine Service Provider
 
Cacique's Avatar

Join Date: Aug 2008
Location: UK
Boat: Vancouver 27
Posts: 234
Re: Every boat dragged bar one!

Has anyone else used an Angel or Chum? I have a 20kg lead weight with a swivel that I can shackle direct to the chain.
__________________
Cheers Jamie
https://www.sailingcacique.com/
Cacique is offline   Reply With Quote
Old 24-09-2012, 14:52   #12
Registered User

Join Date: Nov 2011
Location: Montegut LA.
Boat: Now we need to get her to Louisiana !! she's ours
Posts: 3,421
Re: Every boat dragged bar one!

All I know about anchoring, I learned in the PNW as a young man ! And I don't anchor anywhere I can't use at least 5 to one scope! If I can't because of others, that are already there I move on till I can use 5 to 1. just my way and Im to old to change !I would rather be at sea then in a anchorage with less then this amount of scope! just my 2 cents
__________________
Bob and Connie
bobconnie is offline   Reply With Quote
Old 24-09-2012, 16:00   #13
CF Adviser
 
Bash's Avatar

Join Date: Dec 2008
Location: sausalito
Boat: 14 meter sloop
Posts: 7,260
Re: Every boat dragged bar one!

Quote:
Originally Posted by Cacique View Post
Has anyone else used an Angel or Chum? I have a 20kg lead weight with a swivel that I can shackle direct to the chain.
Most cruisers around these parts call it a "kellet." I've heard "angel" before, but never "chum."

Learn something every day.
__________________
cruising is entirely about showing up--in boat shoes.
Bash is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Advertise Here


All times are GMT -7. The time now is 07:16.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.