Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 08-03-2010, 03:17   #1
Registered User
 
FraidNot's Avatar

Join Date: Nov 2009
Boat: Oceanis 411
Posts: 239
Anchor Chain - How Much?

Benny 41 has 190' (57m) of 3/8th chain.
It is looking pretty long-in-the-tooth.
The boat is 17,000lb (8 tonne).
I generally put out a lot of chain - and if I'm going to replace this chain I may as well get as much as I'm comfortable with.
I notice that the 190' of 3/8th is about 135kg.
I'm tempted to replace this with 250' (77m) - which will allow me 5:1 in 15m of water.
This would weigh about 177kg.
Is this too much ?
By the look of the trim and lie of the boat - I don't think an extra 40kg is an issue.
Opinions and suggestions most welcome.
__________________

__________________
FraidNot
FraidNot is offline   Reply With Quote
Old 08-03-2010, 07:11   #2
Registered User

Join Date: Jan 2010
Location: Gloucester, MA
Boat: CS 36t
Posts: 387
Where do you anchor and what are the greatest depths? Many people who sail around the world end up anchoring in 80+ feet and need a long rode while people who stick to the bahamas rarely anchor in more than 10'. I would suggest making sure that you have 5:1 for the deepest anchorage you expect to see.

Another thing that you can do to save a lot of weight and cost if you expect to anchor in really deep water occassionally is to keep the same amount of chain that you currently have and splice on 150' or so of 3/4" line. You may not want to hang on this in a storm due to chafe but it should be just fine under normal circumstances.
__________________

__________________
klem is offline   Reply With Quote
Old 08-03-2010, 08:46   #3
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
I find 250' the minimum for a world cruiser for all-chain rode. If you are like me, you will often use 120' or less and that makes this length great for turning it end-to-end halfway it's usable service life. I got 300' last time I ordered.

cheers,
Nick.
__________________
s/v Jedi is offline   Reply With Quote
Old 08-03-2010, 09:09   #4
Senior Cruiser
 
Randyonr3's Avatar

Cruisers Forum Supporter

Join Date: Nov 2007
Boat: Beneteau FIRST 42
Posts: 1,836
Because our goat is it leave and not know where we are headed, we've set up two lengths of 400 ft each.. and we use 3/8 BBB .. a smaller size with higher strength..
__________________
Randyonr3 is offline   Reply With Quote
Old 08-03-2010, 09:23   #5
CF Adviser
 
Bash's Avatar

Cruisers Forum Supporter

Join Date: Dec 2008
Location: sausalito
Boat: 14 meter sloop
Posts: 7,260
I have found 250' to be sufficient, but would be able to back that up quickly with nylon if I ever come into a situation where I'd need to anchor in more than 50 feet.

Like Nick, I have found it useful to switch the rode end-for-end to extend its useful life. Unlike Nick, I have no idea when a chain needs to be retired. I'd love to know, I think, except that Nick has been causing me to spend too much money lately.
__________________
cruising is entirely about showing up--in boat shoes.
Bash is offline   Reply With Quote
Old 08-03-2010, 09:58   #6
Registered User

Join Date: Apr 2007
Location: house-North Vancouver BC boat-barra de navidad
Boat: c&c landfall 43
Posts: 120
currently cruising in mexico and we have 300' 3/8 bbb and 150' 3/4" rode for back up. roughly every where we anchor is no more than 30' . Most cruisers we've met have roughly the same in chain. limmer.
__________________
limmer is offline   Reply With Quote
Old 08-03-2010, 15:28   #7
Senior Cruiser
 
Jim Cate's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 11,468
G'Day Fraidy,

First, we've had about 280' of 10 mm on each of our Insatiables, and have found this to be adequate for our purposes. We live on the hook throughout the S Pacific, and have never had to anchor in more than 85', and rarely over 60'. On I-one we had a long bit of nylon spliced to the bitter end of the chain "just in case", but never actually used it. In our experience, the oft-quoted 5:1 or 7:1 scope requirement is not particularly valid at larger depths. I won't get drawn into yet another theoretical battle about calculated anchor loads, but rely on our hard won experiences which say that somewhere around 3:1 in greater depths has worked. When faced with impending cyclones, we have sought out anchorages where more reasonable depths were available!

As to ageing chain -- what do you mean "long in the tooth"? If you mean surface rusting, then re-galvanizing is a much cheaper alternative to replacement. If the chain is significantly worn (in the area where the links bear upon each other), then replacement is in order. Also if the chain has ever been stressed to the point of slight elongation I'd replace it.

And the chap who is carrying two 400' lengths of 3/8" chain in his once lightweight Benny... that's REALLY a lot of weight to carry about, and may represent a bit of overkill!

Cheers,

Jim and Ann s/v Insatiable II lying Towlers Bay, NSW, Oz
__________________
Jim and Ann s/v Insatiable II , lying Port Cygnet, Tasmania once again
Jim Cate is online now   Reply With Quote
Old 08-03-2010, 16:49   #8
Senior Cruiser
 
Randyonr3's Avatar

Cruisers Forum Supporter

Join Date: Nov 2007
Boat: Beneteau FIRST 42
Posts: 1,836
Quote:
Originally Posted by Jim Cate View Post
G'Day

And the chap who is carrying two 400' lengths of 3/8" chain in his once lightweight Benny... that's REALLY a lot of weight to carry about, and may represent a bit of overkill!

Cheers,

Jim and Ann s/v Insatiable II lying Towlers Bay, NSW, Oz
Even thou shes a benny, shes pretty heavy at 24k across the scale empty.. The book says 18.5 but I've got the weight tickets.. and one length is run down thru a pipe to just forward of the keel so most of the weight is off the bow.. Even with the added weight, she's well balanced.
I just dont ever want to be caught with less than I need......
__________________
Randyonr3 is offline   Reply With Quote
Old 10-03-2010, 06:06   #9
Registered User

Join Date: Feb 2008
Posts: 2,062
Quote:
Originally Posted by Randyonr3 View Post
Even thou shes a benny, shes pretty heavy at 24k across the scale empty.. The book says 18.5 but I've got the weight tickets.. and one length is run down thru a pipe to just forward of the keel so most of the weight is off the bow.. Even with the added weight, she's well balanced.
I just dont ever want to be caught with less than I need......
So it's 6k over designed weight to-start? (A serious quality issue). You could make a big improvement if you lighten the load. She may be well balanced, but her performance could improve significantly. There are good arguments for mixed-rode providing better holding than all-chain.

References:
http://www.petersmith.net.nz/boat-anchors/catenary.php
Catenary & Scope In Anchor Rode -- Anchor systems for small boats” by Peter Smith)
http://alain.fraysse.free.fr/sail/rode/rode.htm
“Tuning an anchor rode” by Alain Fraysse
__________________
SailFastTri is offline   Reply With Quote
Old 10-03-2010, 07:31   #10
Registered User
 
Tom Hildebrandt's Avatar

Join Date: Apr 2009
Location: Beaufort, NC
Boat: Radford 40
Posts: 149
I just went through this decision making process after arriving in the Carib. In my trip from Australia through Indonesia, across the Indian Ocean, around Africa and across the South Atlantic to Brazil and on to the Caribean, I had 100 meters of cheap chinese 3/8 chain as my main bit of gear with a muir horizontal windlass. All went well until the chain started skipping here in the Carib. The problem was general wear and tear of the chain, which may also have become a bit elongated as well, and a chainwheel that was also feeling its age of 15 years of heavy use as I was on the hook almost exclusively for the past five years.

I am getting a new chain wheel, and I decided to go with two sets of 200 feet of 3/8 HT chaiin with a 150 foot 9/16 rode spliced to the chain as replacement for the 100 meters. This will be a new arrangement for me, and there is the possibility that the rode will not be grabbed from the chain wheel very well, but after talking to the muir folks, I think I will be ok as there will always be the weight of the chain providing tension on the rode when the I am retrieving the anchor .

My thinking was that the two or three times there was no choice but to to anchor in water deeper than 60 feet or so, I would have been better off having chain and rope than all chain. I prefer to anchor betweeen 20- 30 feet most of the time, so normally I will be riding to all chain. (I also use a longer snubber than most folks, about 40 feet of three strand nylon). By having two full sets of gear , if one should decide to take a permanent leave of abscence, I will still have a a proper replacement!

If the chain starts wearing, I will cut off the splice and end for end the chain and the roode and resplice. The weight will be about the same as I used to carry 30 meters of chain in the locker as a spare, and the bulk should be about the same as well. I am also installing a chain stopper to keep surge loading off the windlass when retrieving the chain. When I have the funds, I will probably replace my aging clone 20 K CQR with a Ranchor 20 K.

Juno is a monhull, a Radford 40, steel hull and aluminum deck, and I am guessing she weighs 16 tons with normal provisioning. Maybe this haul out I will be on a lift that has a weighing device that actually works!

Most cruisers in the 36- 45 foot range that I met had 100 meters as their primary rode, except for the small boats less than 35 feet They all said they just did not want to be hassled with handling nylon rode, and they felt the extra weight on the bottom was a plus. But as W. Van Dorn discusses in excruciating techniacal detail in the book Oceanography and Seamanship, this is not such a great idea since chain does not not stretch and the weight really does not serve to add significantly to holding power in most situations.

Hope this helps!

Tom
__________________

__________________
Tom Hildebrandt is offline   Reply With Quote
Reply

Tags
anchor

Thread Tools
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
How Much Anchor Chain ? Jigsaw Anchoring & Mooring 13 14-12-2010 11:33
Anchor Chain ron henderson Anchoring & Mooring 8 19-06-2009 02:57
3/8 Anchor Chain roscoe Classifieds Archive 2 14-05-2009 14:03
Anchor Chain markpj23 Health, Safety & Related Gear 48 17-11-2007 03:38
Anchor chain irwinsailor General Sailing Forum 3 17-06-2005 23:56



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 21:05.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.