Go Back   Trawler Forum > Trawler Forum > General Discussion

Thread Tools Display Modes
Old 04-22-2009, 06:24 PM   #1
Scraping Paint
City: -
Country: -
Join Date: Oct 2007
Posts: 13,748
Choosing an anchor (longish)

This article was recently published in the UK.* Interesting reading.


Choosing An Anchor
by Alain Hylas (Inventor of the 'Spade' anchor)

To select an anchor, I will base my choice on three points:


Your anchor is your best insurance and, like your insurance, it seems expensive only before the accident occurs. When the weather deteriorates and your boat drags towards the rocks, it is too late to regret the tens of pounds saved on the purchase price. If your boat is tossed on the shore, then the cost may well be thousands of pounds. Security and quiet nights at anchor don't have a price.

The weight of your anchor has almost no relation to the holding. Holding is related to :

The stability of your anchor
Its surface area
The shape of the holding surface

All recent tests have proved that aluminum anchors have the same holding as steel anchors of the same size (Practical Sailor, Bateaux, Voiles magazine.)

However, weight is very important for the PENETRATION of the anchor. If you choose a light (i.e. aluminum) anchor, then favour stable models, those with a penetrating angle like a chisel and those with a heavily weighted tip. (More on this later.)

Efficiency of an anchor is a function of both penetration and holding.

To ensure good holding, an anchor must first penetrate regardless of the sea bottom type, as quickly and deeply as possible. Once set, the anchor must not break free regardless of weather conditions. This is a function of anchor stability and the shape and size of the holding surface


Penetration is related to two factors:

1 - Penetrating angle : I will define the working angle of four classical tools:

Spreader: - a tool forming an angle with the material in front of it of less than 70 degres.
Scraper: - a tool forming an angle with the material close to 90 degres
Chisel: - a tool forming an angle with the material in front of it of about 120 degres
Razor: - a tool forming an angle with the material in front of it of more than 150°

- Out of these four tools, only the "chisel" has been concieved for penetration.. ask the Carpenter.!!..

- The penetrating edge has to be as sharp as possible...

2 - Pressure on the tool: More the pressure, easier will be the penetration... Obvious...

Look at the percentage weight on the tip of some classical anchors:
(from Practical Boat Owner, page 80 n° 391 - July 1999)

Fortress 15%
Bügel 16%
Brittany 17%
Danforth 18%
CQR 18%
Delta 28%
Bruce 38%
Spade 50%

The anchor having both the right penetrating 'chisel like' angle and the heaviest tip will have the maximum chance of penetrating, even in difficult sea bottoms such as hard sand, coral and weed


Holding is related to three factors:

Holding surface area

1 - Stability:
In this regard, the conclusion of John Knox (P. 81 - PBO n° 427 July 2002) confirms completely my own observations as well as the results of the tests done by the French "Voiles Magazine":

- Generaly speaking , ALL HINGED ANCHORS are unstable (Plow anchors, fluke anchors) Under strong pulls, they corkscrew and break free.. (and I can explain why..)

-Stable anchors of the new generation could slightly drag under strong wind gusts, but they keep a constant high holding and they will not break free suddenly... (Very SAFE behaviour)

2- Holding surface:
Try to pull one square meter of steel on the bottom, this is quite easy.. Now bury this plate of steel in the bottom an try again.. Holding has nearly no relation with the weight, but is related to:

- The surface area perpendicular with the direction of the pull..

3-* The shape of this surface -
a "wing" shape has an "holding" coeficient of 0.1
a "chevron" shape has an "holding" coeficient of 0.5
a "flat" shape has an "holding" coeficient of 1.1
a "concave" shape has an "holding" coeficient of 1.7

Or in other words, a surface with a "Chevron" shape must be more than three times the area of a surface with a concave shape to have the same holding.

This may seem simple, but in addition:

A good anchor must hold regardless of wind and /or current change of direction.
lt sould not have the possibility to become tangled with the anchoring rode.
lt should not require any specific anchoring technic.
lt should fit snugly on a the bow roller
Used with an electric windlass, it should be self launching and retrieving .
lt should be very strong

As you will have noticed, I haven't mentioned any brand names . . . this will be YOUR responsibility..

If you assess all models, and can find one that has all the characteristics mentioned in the article, then you can be sure you have made a good choice.

Marin is offline   Reply With Quote
Old 04-23-2009, 12:14 PM   #2
City: Carefree, Arizona
Country: usa
Vessel Name: sunchaser V
Vessel Model: DeFever 48
Join Date: Apr 2008
Posts: 5,339
RE: Choosing an anchor (longish)

Lots of gobbledeeguk out there on anchors. So here is mine:

Bigger is better!! If buying new, I'd go with Rocna. I have a 30 kg , all chain rode, Bruce now - real not*counterfeit. My spare, never deployed, is a 32# Fortress - because they are easy to stow.

sunchaser is offline   Reply With Quote
Old 04-23-2009, 02:33 PM   #3
Scraping Paint
City: -
Country: -
Join Date: Oct 2007
Posts: 13,748
RE: Choosing an anchor (longish)

We have a Rocna now. It replaced a Bruce which, the more we used it the less we liked it and the more trouble it tried to get us into. It now makes a great doorstop in our garage. I would never put one on a boat again.
Marin is offline   Reply With Quote
Old 04-23-2009, 03:26 PM   #4
Senior Member
Join Date: Oct 2007
Posts: 272
RE: Choosing an anchor (longish)

Agreed on the Bruce, I have one that makes a good door stop for my storage locker.
I got scolded on the T&T list from some know it all but I have been happy with a Fortress FX55.
troy994719 is offline   Reply With Quote
Old 04-27-2009, 07:27 AM   #5
Veteran Member
wingspar's Avatar
City: Blaine
Vessel Name: White Star
Vessel Model: Canoe Cove
Join Date: Jan 2008
Posts: 79
RE: Choosing an anchor (longish)

I've tried most of them and dragged them from the Danforth, Bruce and CQR with the Bruce being my least favorite. Meet someone on the dock about 10 years ago with a funny looking anchor that I've never seen before. It was a Super Max. Said he had good luck with it so I ordered one out. Yes, it was expensive. However, now after 10 years of use, finally, an anchor that sets every time in ALL bottom condition up here in the PNW from thick mud, grass, rocky bottom, etc. Now I no longer get up every few hours to check the anchor as it is the only anchor I've never dragged. Now my only worries when the wind pipes up is some other boat dragging his anchor over mine. But thats happened only once.

wingspar is offline   Reply With Quote
Old 05-01-2009, 07:41 AM   #6
Phil Fill's Avatar
City: Everett Wa
Country: US
Vessel Name: Eagle
Vessel Model: Roughwater 58 pilot house
Join Date: Oct 2007
Posts: 2,869
RE: Choosing an anchor (longish)

The anchor that is dominate on the large pleasure, 50+ ft and the commercial fish boats in the PNW is the Forjord which is navy style/type anchor.* We have three anchors a CQR, Danforth and a Forjord.* The CQR is a plow and does not hold well in soft sand/mud bottoms as it just ploughs.* The Danforth, holds well in the soft mud bottoms but gets fouled in heavy bottom growth.* The Forjord is our primary anchor and sort of fits between the CQR and Danforth.

I tend to follow what the larger commercials and/or pleasure boats use.* I wish the Eagle windless was bigger as I would feel more comfortable with a 150 lb anchor than a 75 to 100 lb anchor as weight does seem to matter.* *


Phil Fill is offline   Reply With Quote

Thread Tools
Display Modes

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
Choosing Dingy Davits for Your Trawler marinetrader Dinghys and Smaller Boats 16 Yesterday 07:16 PM
Advice on Choosing a Boat BlueSky General Discussion 56 02-22-2012 02:17 AM
Choosing the Right Anchor for Your Trawler marinetrader Anchors and Anchoring 171 10-15-2010 05:19 AM
Choosing a Marine Varnish marinetrader General Maintenance 10 11-26-2009 08:38 PM
Choosing an Autopilot??? DonW Electrical and Electronics & Navigation 7 05-30-2008 10:36 PM

All times are GMT -5. The time now is 04:29 PM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012