Bahamian Mooring - SailNet Community
 4Likes
Reply
 
LinkBack Thread Tools
post #1 of 25 Old 10-06-2011 Thread Starter
Senior Moment Member
 
SloopJonB's Avatar
 
Join Date: Jun 2011
Location: West Vancouver B.C.
Posts: 12,425
Thanks: 78
Thanked 84 Times in 81 Posts
Rep Power: 5
 
Bahamian Mooring

I am seeking opinions on using a Bahamian mooring instead of a conventional huge block of concrete for a summer mooring for a 43', 11 ton boat.

What I have in mind is using two BIG anchors - 150# each or so, linked by chain with a chain shackled from the middle of the span rising to a buoy. The proposed mooring spot is reasonably sheltered but the wind CAN blow and the seas can reach maybe two feet.

My reasons for wanting to do it this way are twofold - I don't want place an essentially permanent lump there and I would like to do it myself, not requiring a barge, crane etc. and the purchase of the aforementioned lump.

I figure I can pick up a couple of decent big anchors for less than the lump would cost and they are retrievable relatively easily when the time comes.

Thoughts?

I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.
SloopJonB is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 25 Old 10-06-2011
Senior Member
 
Gene T's Avatar
 
Join Date: May 2006
Location: Left Coast USA
Posts: 666
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
First thing that comes to mind is are you planning to set the anchors, or just drop them in place. Also anchors need scope to work properly. Are you planning to use the appropriate scope? It would certainly work if set and using proper scope.

Gene


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

Currently in Long Beach, CA
Gene T is offline  
Quote Quick Reply Share with Facebook
post #3 of 25 Old 10-06-2011
Senior Member
 
Join Date: Oct 2009
Location: Gloucester, MA
Posts: 586
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
 
I would advise against using a bahamian mooring setup as a permanent mooring. If the wind blows perpendicular to how the anchors are laid out, you can end up with very high loads on the anchors unless you have left a lot of slack in their chains and then you end up with changing directions of pull.

If you are set on doing a multiple anchor setup, a 3 point setup works well if setup properly. Getting the ratio of chain in the legs to chain in the leader from the legs to the ball right is very important. Additionally, getting the correct amount of slack in the chains is key. Believe it or not, you need some slack or you will greatly increase the loads on the anchors because they will be reacting against each other. Also, you need to have a good way of attaching everything that will not twist up. When properly done, this provides excellent holding power but when improperly done, loads can be greatly magnified or direction of pull on the anchors can change a lot. I would highly recommend drawing out free body diagrams and figuring out how much load is on each point for given geometries if you decide to go this way. Doing this will help a lot in figuring out what the geometry should be.

What is the bottom where you are? If you have sufficient tide and the bottom is decent, you can move an appropriate size mushroom or pyramid with your boat as long as you are careful. By driving the gear down to the low tide line and then coming over it with just a little tide left to do the final lifting, you can use the boat's buoyancy to pick it up. Just be careful to rig it so that you can lower it in control down to the bottom.
klem is offline  
Quote Quick Reply Share with Facebook
post #4 of 25 Old 10-07-2011
Member
 
Join Date: Aug 2004
Location: CT / St John USVI
Posts: 30
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Send a message via Skype™ to Windborn
Can you use screws?

Our mooring consists of 5 screws linked with heavy chain. A 20' chain connected to the screw's chain has two 3/4" pendants that come up to the boat. We've survived hurricane hits with this setup.
Windborn is offline  
Quote Quick Reply Share with Facebook
post #5 of 25 Old 10-07-2011
Senior Member
 
Join Date: Oct 2009
Location: Gloucester, MA
Posts: 586
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
 
Windborn,

Out of curiosity, do you have a wave of equalizing the load on your screws? I am not a fan of most multiple anchor moorings because there is not load equalization and you can pull out each anchor one by one. There are ways obviously to deal with this but I have rarely seen it effectively done.
klem is offline  
Quote Quick Reply Share with Facebook
post #6 of 25 Old 10-07-2011 Thread Starter
Senior Moment Member
 
SloopJonB's Avatar
 
Join Date: Jun 2011
Location: West Vancouver B.C.
Posts: 12,425
Thanks: 78
Thanked 84 Times in 81 Posts
Rep Power: 5
 
Quote:
Originally Posted by Gene T View Post
First thing that comes to mind is are you planning to set the anchors, or just drop them in place. Also anchors need scope to work properly. Are you planning to use the appropriate scope? It would certainly work if set and using proper scope.

Gene
I had thought to set them, one at a time, facing each other with a length of chain equal to proper scope across. I figured the pull from a near vertical chain in the middle would have a vector that would try to pull them together rather than up (basically).

The bottom is is mostly rock and shale. I had planned to have a diver check the set of them prior to use.

I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.
SloopJonB is offline  
Quote Quick Reply Share with Facebook
post #7 of 25 Old 10-07-2011
Senior Member
 
JimsCAL's Avatar
 
Join Date: May 2007
Location: Glen Cove, NY
Posts: 3,077
Thanks: 2
Thanked 95 Times in 89 Posts
Rep Power: 9
 
I think Bene505 uses a multi[ple anchor system to moor his boat at Montauk. You might PM to get his experiences.
JimsCAL is offline  
Quote Quick Reply Share with Facebook
post #8 of 25 Old 10-07-2011
Senior Member
 
Join Date: Nov 2010
Location: Baltimore
Posts: 833
Thanks: 47
Thanked 24 Times in 17 Posts
Rep Power: 6
 
screws?

Quote:
Originally Posted by Windborn View Post
Can you use screws?

Our mooring consists of 5 screws linked with heavy chain. A 20' chain connected to the screw's chain has two 3/4" pendants that come up to the boat. We've survived hurricane hits with this setup.
Can you be more specific? Helix anchors (TM) or something else? How did you get them in? What kind of situation (bottom, exposure, boat size)?

Thanks for any information on this. I am considering getting a mooring set-up for a hurricane situation.
MastUndSchotbruch is online now  
Quote Quick Reply Share with Facebook
post #9 of 25 Old 10-07-2011
Senior Member
 
paulk's Avatar
 
Join Date: Jun 2000
Location: CT/ Long Island Sound
Posts: 2,665
Thanks: 4
Thanked 30 Times in 29 Posts
Rep Power: 16
 
Our harbor uses helix anchors for strings of 6 or more boats. In the recent Hurricane/Tropical Storm Irene, the main concern was not that they would pull out, but that boats would be held down by their anchors and sunk when the water rose over their gunwales. We're talking 30 to 40 foot cruising keelboats - not daysailers. Crews went around lengthening the mooring lines to accommodate the extra four feet or so of water we got at high tide that day, and nothing happened.

Last edited by paulk; 10-07-2011 at 10:56 PM.
paulk is offline  
Quote Quick Reply Share with Facebook
post #10 of 25 Old 10-07-2011
Just another Moderator
 
Faster's Avatar
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 17,439
Thanks: 119
Thanked 387 Times in 367 Posts
Rep Power: 10
     
With your center-chain pull I wonder if you wouldn't have some very high loads on the system if you ended up pulling hard at 90 degrees to axis of the two anchors.. (similar to how a crosswind in a stern/shore tie situation can put heavy loads on the hook)

btw.. where are you going to try this??

Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
Faster 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
Duarte Marine Makes Mooring Easy, Debuts First Single-Handed Mooring System - PR Web NewsReader News Feeds 1 10-06-2011 02:58 PM
Using a snatch block for a Bahamian Moor labatt General Discussion (sailing related) 12 04-09-2009 07:22 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