sail-world.com
 
 
News Home Cruising Photo Gallery Video Gallery
Sail-World.com : Use this simple secret for anchor holding power!
Use this simple secret for anchor holding power!

.

The other day, a reader sent in a query as to why I recommend a 7: 1 scope on anchor rode as opposed to 3:1. After all, less rode means less hassle with having all that line messed up by gooey mud, slimy bottom crud, and other unknowns beneath the sea.

Use enough scope to match the conditions you anchor in. You scope calculation should include present depth, expected rise to high tide, distance of your depth sounder transducer below the waterline, and freeboard (height of the bow above the water). Add all of these factors up. Multiply by seven for an average scope. Why so much?

Here's a simple, eye-opening demonstration of the power of anchor scope, which is easy for you to do in your home waters:

Grab a small anchor (Five pounds or less--easy to handle). The anchor type isn't important--even a tiny grapnel will do. Attach 20 feet of small diameter line to the anchor shank (long arm of the anchor).

Locate a sandy or soft ground area. Dig the anchor flukes into the ground just a bit. No need to bury them all the way. Walk to the end of your 20 foot anchor line. Turn around and face the anchor. Pull hard on the rope rode. What do you notice?

Your anchor will dig into the simulated 'seabed' and hold well. That's because most of the pull on the anchor rode will be horizontal. And that's the secret to keep your anchor dug deep. You want to do everything possible to keep the rode as parallel as possible to the seabed.

That's another reason to use a length of chain at the seabed end of a rope anchor rode if you are using rope. The chain protects the line from chafe (wear) and it provides weight to keep the rode more parallel to the bottom.

Now, let's simulate what happens with just 3:1. In our experiment, we will assume what the 20 foot piece of rope at the end represents a scope of 7:1. So, about half of that length would represent a scope of close to 3: 1.

Walk slowly toward your anchor. Keep tension on the rope rode as you go. Watch the angle that the rode makes with the anchor and sea bed. Stop when you get to a point about ½ of the distance to the end of the rode.

Look at the shank of your anchor. Note that the rode now has an upward (vertical) pull on the end of the anchor shank. Any vertical pull on an anchor shank has the potential to break out an anchor and cause it to drag. The shorter the rode relative to the water depth, the less chance that your anchor will hold. Avoid short scope for long term or overnight anchoring. Longer scope gives your anchor greater holding power over a broader range of wind or sea condition.

Remember, you will not always anchor on a flat plane of water. Wave action, ground swell, and boat wakes cause your boat to lift and fall in position. As we saw in our experiment, any vertical pull on the anchor will decrease holding power and increase the possibility of break out and dragging. Use longer rode to lessen vertical pull when your boat bow lifts and falls in choppy anchorages.

But what about vessels with all-chain rode? Sure, those with heavy chain might use shorter scope of about 5:1 in light to moderate conditions. But 7:1 will always be better. And, in storm conditions or in unprotected areas with heavy ground swell, you need 10:1. Use the maximum scope possible or set more than one anchor in crowded anchorages with limited swing room.

You will sleep better at night when you choose to use enough scope to keep your boat anchor dug deep into the sea bottom--wherever in the world you choose to cruise!

John Jamieson (Captain John) with 25+ years of experience shows you the no-nonsense cruising skills you need beyond sailing school. Visit his website at www.skippertips.com for a free sailing tips newsletter. Become a member for instant access to 550+ sailing skills articles, 100+ sailing video tutorials, 145+ sailing tips newsletters, 12+ sailing topic e-Books, and more!


by John Jamieson

  

Click on the FB Like link to post this story to your FB wall

http://www.sail-world.com/index.cfm?nid=96785

11:47 AM Thu 3 May 2012GMT


Click here for printer friendly version
Click here to send us feedback or comments about this story.







News - USA and the World





















Audi Melges 20 U.S. Nationals - Oleander takes early lead by International Audi Melges 20 Class Association,






2014 Detroit Cup - Sam Gilmour leads by Dobbs Davis, Detroit, Michigan








Audi Hamilton Island Race Week: Riding the AC45 - VIDEO by Crosbie Lorimer, Hamilton Island










America's Cup: Five Challengers sign-on for 35th Match by Richard Gladwell/Sail-World.com/nz,


Volvo Ocean Race CEO Knut Frostad talks Time and Money (Part II) *Feature by Rob Kothe and the Sail-World team,


















AWT Quatro Desert Showdown at Punta San Carlos by American Windsurfing Tour,


SAP 505 World Championship - Holt and Woelfel on top
2014 IFDS Disabled Sailing World Championship - Day 2
Audi Hamilton Island Race Week; MC38s Lindeman Island Race VIDEO
2014 Audi Melges 20 U.S. National Championship - Ready to rock
IFDS Worlds - Wind delays, but racing continues in Halifax
IFDS World Championships - Day 2 images by Jude Robertson
MS Cup - Three days until the start
America's Cup: Rod Davis - Time for a change after ten years with team *Feature
ISAF seeking hosting bids for Nations Cup
Laser 4.7 Youth Worlds - Luvisetto and Alexadr Boite victorious +Video
IFDS World Championships - Action shots by Tim Wilkes
Maxi yacht rendezvous this September in Sardinia
World Yacht Racing Forum 2014: 'Growing the business of Yacht Racing'
Clipper Race: 2015-16 edition of world's longest ocean race 70% full
Sevenstar Round Britain and Ireland - Swish smash 5th World Record
Leaderboards take shape at the Nanjing Youth Olympic Games 2014
IFDS Worlds - Hot competition on first day of racing
Challenging Conditions - CORK OCR
IFDS World Championship - Day 1 for the US Sailing Team
2014 Melges 20 World Championship - Countdown begins
2014 Nanjing Youth Olympic Games - Day 3   
America's Cup: Team NZ wish Davis well with new team *Feature   
Fisher's View: Sailing perfection at Hamilton Island- Day 3   
Roble and Wilson still number one match racers in the U.S.   
2014 Formula Kite World Championship Day 1   
IFDS World Championship - Day 1 images by Jude Robertson   
Volvo Ocean Race: Forget the f-word - Team SCA profiled   
52 Super Series - Fleet grows, 2015 dates revealed   
420 and 470 Junior Europeans - Teams from 9 nations on the podium   
IFDS Worlds - Former president presented with ISAF awards medal   
Nanjing Youth Olympic Games - Improvements aplenty in Byte CII fleets   
America's Cup: New Zealand loses top coach to Artemis Racing   
Volvo Ocean Race 2014-15 CEO Knut Frostad talks (Part I) *Feature   
Sevenstar Round Britain and Ireland Race Day 9 - Swish on record pace   
2014 CORK Olympic Classes Regatta - Day 3   
2014 Nanjing Youth Olympic Games - Day 2   
2014 IFDS World Championship: Opening Ceremony images   
Opera House Cup - Images by Ingrid Abery   
Teams descend upon Cowes for inaugural J/111 World Championships   
Hamilton Island Race Week: Everywhere there's smiley people   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News







Sail-World.com  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png http://www.sail-world.com/event_images/image/FaceBook-icon.png  http://www.sail-world.com/event_images/image/RSS-Icon.png

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph contact the photographer directly.
XLXL WAS US
LocalAds   DE  ES  FR  IT