Mooring Question - SailNet Community
Seamanship & Navigation Forum devoted to seamanship and navigation topics, including paper and electronic charting tools.

 
LinkBack Thread Tools
post #1 of 8 Old 07-31-2007 Thread Starter
S/V Perwinkle
 
Join Date: Sep 2006
Location: Sarasota
Posts: 22
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Mooring Question

There is a mooring at my club that is available for rent. My question ... is a 1/2 inch chain strong enough for an 18,000 lb boat. I'm being told, "no problem" but my instincts tell me that seems on the light side for a boat of that displacement.

Thanks,
Lawson
lmitchell is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 8 Old 07-31-2007
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 15 Times in 12 Posts
Rep Power: 14
         
Lmitchell-

It really depends. If it is G70 or G40/43 chain, it probably is just fine for your boat. 1/2" chain is pretty massive.

I doubt that your windlass uses more than 3/8" chain.

BTW, 1/2" G43 High-test chain has a SWL of 9200 lbs. I seriously doubt that the mooring itself can handle that much strain, unless it is a large diameter square-shaft helix mooring. The mooring system is only as good as the weakest link, which would probably be your mooring pennant.

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.

Last edited by sailingdog; 07-31-2007 at 05:23 PM.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #3 of 8 Old 07-31-2007
San Juan 26
 
LittleMissMagic's Avatar
 
Join Date: Oct 2006
Location: Robertsdale, AL
Posts: 395
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
 
If you can get your hands on a Mar/Apr issue of Good Old Boat there is a good article concerning moorings. If I remember correctly, there is a formula for figuring out what size chain, weight, etc. you need for your boats displacement.

Jon Caisson Bozeman
S/V Little Miss Magic, Pirates Cove, AL
LittleMissMagic is offline  
Quote Quick Reply Share with Facebook
post #4 of 8 Old 07-31-2007
Missionary
 
Join Date: Jan 2007
Location: Smithfield, Virginia
Posts: 23
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Has the chain been inspected by a diver. Chain wears it may have started at 1/2 but has worn to only 1/8 in one place and may break any time. Inspection will ease your mind.
Missionary is offline  
Quote Quick Reply Share with Facebook
post #5 of 8 Old 11-10-2007
Senior Member
 
merttan's Avatar
 
Join Date: Oct 2007
Location: CT
Posts: 317
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
 
I need to know...

There are some unknown factors if you want to share;
Mooring weight.
Mooring line lenght.
Your boats hull height from the waterline.
Type (grade) of chain.

Then I may be able to make a calculation for safety of the chain for known/perfect condition. The known/perfect condition is being that we assume you don't have a weak link such as a weak connection on mooring weight or line, and your cleats are permanent to the boat...

Your boat is moored by the weight of the mooring post, suction of the mud at the bottom,chain strength, and the angle of mooring line (That's why they recommend using a 7:1 ratio for over night anchorages)...

" I refuse to engage in an intellectual battle with an unarmed man!"

Materialism: Buying the things we don't need, with money we don't have, to impress people who don't matter.

Last edited by merttan; 11-11-2007 at 12:01 AM.
merttan is offline  
Quote Quick Reply Share with Facebook
post #6 of 8 Old 11-10-2007
me at 67!
 
deniseO30's Avatar
 
Join Date: Nov 2006
Location: Bristol pa
Posts: 6,966
Thanks: 55
Thanked 126 Times in 115 Posts
Rep Power: 10
   
I had the guys put 20ft of 5/8" for bottom chain and I have 5/16 for my 11,000 lb oday 30. the river here has a tidal rush up to up to about 8 knots.
I would rather the mooring move then the chain break because it just resets not too far away. when the chain breaks... bye bye boatie!

Denise, Bristol PA, Oday 30. On Tidal Delaware River, Anchor Yacht Club.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

My last project!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


My boat is sold!
deniseO30 is offline  
Quote Quick Reply Share with Facebook
post #7 of 8 Old 11-11-2007
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 15 Times in 12 Posts
Rep Power: 14
         
Merttan-

Not all moorings are weight depended, and the mooring anchor's material makes a huge difference in its holding ability. A 500 lb. block of iron is going to be far better than 500 lbs. of concrete, since iron is far denser and has a much higher effective weight underwater. Many new moorings are helical screw, and basically limited by the type of bottom and what size screw they used. In some tests these helical mooring anchors rated well over 20,000 lbs of resistance before yielding.

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #8 of 8 Old 11-11-2007
humble pie rat
 
CapnHand's Avatar
 
Join Date: Nov 2006
Location: Location, Location
Posts: 867
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
 
Quote:
Originally Posted by LittleMissMagic View Post
If you can get your hands on a Mar/Apr issue of Good Old Boat there is a good article concerning moorings. If I remember correctly, there is a formula for figuring out what size chain, weight, etc. you need for your boats displacement.
It was graciously posted here by the good people at Good Old Boat: Mooring systems

There are 10 kinds of people. Those who understand binary and those who don't.
CapnHand is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Dumb Question about Mooring flyingdiva Boat Review and Purchase Forum 7 06-24-2007 10:23 PM
Special Mooring Challenge like2sail General Discussion (sailing related) 17 04-12-2007 09:51 AM
Mooring Equipment question Dcneuro Bristol 0 11-08-2006 08:39 AM
Mediterranean Mooring John Kretschmer Seamanship Articles 0 12-22-2003 07:00 PM
The Mechanics of Mooring Mark Matthews Seamanship Articles 0 05-19-2002 08:00 PM

Posting Rules  
You may post new threads
You may 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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome