How to Test Anchors?

[Kettlewell]

No, this is not about any particular anchor. I've just been mulling over in my mind what has been wrong with the various anchor tests I have read about. Here are some thoughts on what I would want to do in an anchor test. I would want to test a selection of mainstream anchors that are readily available at retail in major USA stores. I would want to test equal weights amongst anchors of vaguely similar shape and material. In other words, fixed shank "new generation" anchors should be the same weight. Aluminum anchors would be chosen based on the manufacturer's recommendation to match the steel anchors of that weight. The rode would be all chain or maybe all dyneema, but maybe one or two sizes too big to avoid breaking. The anchors should be of a decent size--at least 35 or 45 pounds, as I think there are some scale effects on these tiny anchors that are often tested. The pulling boat should be capable of producing enough power to get up over 5-6000 lbs of pull. The anchors should be set at 7:1 as the main test for maximum holding. Each anchor should be tried say 10 times in the same area, adjusting scope to maintain the 7:1 scope if the tide changes. I would like to see tests in good East Coast mud, which is my typical anchoring ground, plus in good clean deep sand someplace like Florida. I think the unusual hard bottoms, like in the infamous West Marine test, do tell us something, but it is not a typical situation. Most importantly, the anchors should be set carefully and properly: lower to the bottom until the anchor just touches down, then gradually and slowly drift or motor back paying out rode by hand, snubbing gently periodically to work the anchor in, etc. I hate these tests where they throw the anchor over and a dog pile of chain on top and then back down like crazy.

What would you like to see in an anchor test?

[sarafina]

A really hunky guy in ratty cutoffs lowering the chain offa the bow of a really hot looking monoh... oh. well maybe that's not what you had in mind ; -)

I want to see the anchor tested at tidal changes to see how they hold as the boat and rode swing to the new current... Seems to me like that is often when an anchorage fails for me... held in one direction, but lost and drug in the turnaround...

[Kettlewell]

Sarafina, maybe we should have a guy and a girl in appropriate shorts alternating on the lowering. The tidal thing would be interesting, but it would take too long and 99% of the time there wouldn't be enough wind to do the test justice. In some tests I have seen they try to simulate this by pulling the rode from the opposite direction, but that is difficult to do if the wind is blowing too hard, the current is pulling the boat one way, etc. I can picture a few bodies of water where you might be able to simulate this by pulling from first one side of the channel using a winch arrangement on land, and then moving the line to the other side of the channel and winching it in from the opposite direction, but it would be hard to get the scopes right and not be pulling the anchor up hill.

[skipmac]

How about some sort of jerking motion to simulate the effect of waves on an anchored boat.

[cal40john]

Have you seen this study?

http://offshore.ussailing.org/Assets...chor+study.pdf

Doesn't have all your requirements, but does compare data from several different tests and bottoms, some are only listed in the appendix.


Doug Fryer listed as author is an interesting person. Co-inventer of the life-sling. Has a neat Perry custom cold molded 42 footer that is traditional looking topside and racer underneath.

John

Originally Posted by Kettlewell

No, this is not about any particular anchor. I've just been mulling over in my mind what has been wrong with the various anchor tests I have read about. Here are some thoughts on what I would want to do in an anchor test. I would want to test a selection of mainstream anchors that are readily available at retail in major USA stores. I would want to test equal weights amongst anchors of vaguely similar shape and material. In other words, fixed shank "new generation" anchors should be the same weight. Aluminum anchors would be chosen based on the manufacturer's recommendation to match the steel anchors of that weight. The rode would be all chain or maybe all dyneema, but maybe one or two sizes too big to avoid breaking. The anchors should be of a decent size--at least 35 or 45 pounds, as I think there are some scale effects on these tiny anchors that are often tested. The pulling boat should be capable of producing enough power to get up over 5-6000 lbs of pull. The anchors should be set at 7:1 as the main test for maximum holding. Each anchor should be tried say 10 times in the same area, adjusting scope to maintain the 7:1 scope if the tide changes. I would like to see tests in good East Coast mud, which is my typical anchoring ground, plus in good clean deep sand someplace like Florida. I think the unusual hard bottoms, like in the infamous West Marine test, do tell us something, but it is not a typical situation. Most importantly, the anchors should be set carefully and properly: lower to the bottom until the anchor just touches down, then gradually and slowly drift or motor back paying out rode by hand, snubbing gently periodically to work the anchor in, etc. I hate these tests where they throw the anchor over and a dog pile of chain on top and then back down like crazy.

What would you like to see in an anchor test?

[Jim Cate]

here's a REALLY scientific test:

At random, buy 20 boating publications. Carefully go through them, cutting out adverts from anchor manufacturers. Sort the clippings into piles, each from one manufacturer. Weigh the piles.

Heaviest pile wins bragging rights in CF.

This methodology is at least as accurate as the ones published IMO!!!

Cheers,

Jim

[foamcore]

I've seen it done on land, a beach really. The anchors were pulled through the sand by a tractor. It was a bunch of guys drinking beer so there were no real results but a good time was had by all.

[Bash]

Originally Posted by Kettlewell

. I hate these tests where they throw the anchor over and a dog pile of chain on top and then back down like crazy.
?

Now you understand why anchor threads are so heated around here.

[S/V Alchemy]

Originally Posted by skipmac

How about some sort of jerking motion to simulate the effect of waves on an anchored boat.

Some sort of jerking motion has appeared in every anchor thread I've ever read, but I keep reading them anyway...

[ActiveCaptain]

A few things that I think are important:

- 180 degree swing reset distance

- initial set distance - how far does it take to set the anchor the first time

- angle of swing before reset occurs

- different scope results (7:1 is nice but 5:1 and 3:1 are important in many circumstances); all tests/measurements should be repeated at each measurement

- price of the anchor

- packed sand penetration, especially as exists in much of the Bahamas

[CarlF]

Alchemy wins

Kettelwell, I'm going to guess that you don't own one of the new gen anchors. Your setting procedure is what I used to do for 20 years with my CQR (plus repeating some particularly powerful spells I learned from a hermit on Isle au Haut).

With the new anchors, I pretty much just throw some chain over and hold onto a stay so I don't fall over when the boat jerks to a stop.

And an anchor that doesn't need a lot of "gentle snubbing" means that I sometimes don't even get out of bed these days when I feel the wind change at 3AM.

A few of the anchor tests have looked at sets, veering and resetting but at the end of the day the reports empahsize straight line pull on a carefully set anchor. That's not my #1 concern.

Carl

[markpierce]

Toss your anchor out and takes your chances.

[GordMay]

Originally Posted by Kettlewell

... I hate these tests where they throw the anchor over and a dog pile of chain on top and then back down like crazy ...

Which particular tests were those?
I don't recall reading any like that.

[doug86]

here is a good place to start:
http://www.cruisersforum.com/forums/...html#post13800

[Auspicious]

I've been working on a test protocol for a couple of years, something that would allow results from different tests at different times to be reasonably compared. I'm a little stuck on bottom composition. I've been looking for a civil engineer with experience in saturated soils to help with material characterization.

I'm still working on mechanisms to realistically evaluate reset on veering.

I think (don't know - need to test!) that different anchor designs may scale differently and so three sizes of each design should probably be tested. Results should be shown by projected area in addition to by weight.

If I can ever get the paper finished I'd like to present at SNAME, perhaps their Small Boats Symposium.