Anchor dragging by night, 45 knots wind, 1.5 m waves, between 3 boats and the beach

[Simi 60]

Originally Posted by Scout 30

It's very important to back down on a CQR till it stops the boat just to make sure it's set. The next gen anchors may set more reliably but I think it's still a good idea unless you're diving the anchor.

Did it once, won't do it again.
To much instant power from our big fan and 65 tonne coming to a sudden stop is something we won't be repeating.

Of course on other vessels without ducted propellers it will be far less of an issue

[Jim Cate]

Originally Posted by Alan Mighty

I was struggling through my dusty pile of old issues of YM and PBO. I think the relevant article is one of:

"Snatching at Anchors," Practical Boat Owner, February 1999 #386, pp 133-135

"Anchoring by Numbers," Yachting Monthly, August 1997 #1092 pp 24-28.

Frustrated that they were out of order and the two key issues are missing, I had a rare moment of inspiration.

Remembering that JH Knox had been marketing his "Anchorwatch" strain gauges, I looked for anchorwatch.co.uk. Seems no longer there. But the Internet Archive has the relevant.

Take a Captain Cook at this:

https://web.archive.org/web/20060824...orwatch.co.uk/

1. on the left hand side, click on the 4th from top "ANCHORWATCH THE SCIENCE"

2. ignore the fact that the images have been lost, and scroll down until you see "CHAIN LENGTH REQUIRED FOR BORDERLINE STATE" and then read carefully until you reach "QUANTITATIVE ANCHORING WITH ANCHORWATCH"

Of course, it's not as good as the original article from YM or PBO. I'll keep searching in hope I find it.

Alan,thanks for doing that searching, and for the chronicling of Dr Knox's career which is one to be admired, especially when the added years of yachting and anchoring research are added in. Dunno if he knew how to weld, but his work with anchoring is pretty interesting!

At any rate, when one delves through the reference, it seems to me that he recommends just about what most experienced cruisers do: use reasonably heavy chain at a minimum of 5 to 1 scope and use a snubber. Interestingly, he says little about the size of anchor.

So, I can stop worrying about where to stow 800 feet of chain!!

Thanks again... very interesting fellow!

Jim

[foggysail]

My thoughts on anchors failing in wind/tide changes is simple. Mine failed in a mud location and I did mention earlier that the anchor needed to be cleaned prior to reanchoring. A mud choked anchor is not going to quickly reset!

There are several videos out there that I have watched showing a quick reset after a load direction change. And in all cases that I saw displaying anchors quickly reseting, NON OF THE VIDEOS showed a mud choked anchor.

So there are videos and there are numerous user reports bragging how the Mansons and Rocnas excel in directional load changes. And I emphasise that these fine reports are conditional and highly dependent on what type of bottom the anchor will quickly reset.

[foggysail]

Originally Posted by Jim Cate

Alan,thanks for doing that searching, and for the chronicling of Dr Knox's career which is one to be admired, especially when the added years of yachting and anchoring research are added in. Dunno if he knew how to weld, but his work with anchoring is pretty interesting!

At any rate, when one delves through the reference, it seems to me that he recommends just about what most experienced cruisers do: use reasonably heavy chain at a minimum of 5 to 1 scope and use a snubber. Interestingly, he says little about the size of anchor.

So, I can stop worrying about where to stow 800 feet of chain!!

Thanks again... very interesting fellow!

Jim

Around here in Massachusetts you are one lucky guy to be able to employ a 5 to 1 scope. Tooooo many boats! The harbors are crowded. Shallow water does help to employ more scope. Even if you "get there first" it means nothing because others will presume there is nothing wrong anchoring close to you. Sure you can attempt to be the anchoring police and you might just collect a bruised nose.

[foggysail]

Originally Posted by Scout 30

Defender has this on clearance: https://www.defender.com/product.jsp?path=-1&id=3900686

Yes but I was being facetious mentioning that huge anchor

[Compass790]

Originally Posted by Scout 30

Can you tell us what your scope was? Do you back down hard on the Mantus when you set it? We've also got a High Tensile Danforth that is a strong anchor with massive holding power but always pulls out with a direction change & then tends to just skip along the bottom instead of resetting, especially if there's any grass.

Our Danforth experiences are similar to yours except it doesnt always pull out in a direction change. Weed is a real problem for them. They can "fly" if you drag fast & the flukes tip up the wrong way but we find ours way better than our spare CQR in sand.

[Scout 30]

Originally Posted by Simi 60

Did it once, won't do it again.
To much instant power from our big fan and 65 tonne coming to a sudden stop is something we won't be repeating.

Of course on other vessels without ducted propellers it will be far less of an issue

Wow, that is a seriously heavy duty boat!

[Scout 30]

Originally Posted by foggysail

Yes but I was being facetious mentioning that huge anchor

Never joke about anchors.

[Cadence]

Originally Posted by Simi 60

Did it once, won't do it again.
To much instant power from our big fan and 65 tonne coming to a sudden stop is something we won't be repeating.

Of course on other vessels without ducted propellers it will be far less of an issue

I love your underwater setup. You could probably pull the bottom up. What did she trawl for during her working days?

[foggysail]

Originally Posted by Scout 30

Never joke about anchors.

Yeah........shame on me

[Simi 60]

Originally Posted by Cadence

I love your underwater setup. You could probably pull the bottom up. What did she trawl for during her working days?

Prawn trawler.
Power comes from a 315 HP Cummins nta855m
Just clicked in gear gets 5 knots @ 800rpm and 7.5 @ 1150rpm

[Scout 30]

Originally Posted by Simi 60

Prawn trawler.
Power comes from a 315 HP Cummins nta855m
Just clicked in gear gets 5 knots @ 800rpm and 7.5 @ 1150rpm

I'm sure I'm not the only one that would love to see more pics. Awsome boat.

[Cadence]

It may be a first seeing a Kortz nozzle here? I love the slow RPM.

[Velella99]

One thing I hear little of is the size of the anchor that is used. With modern sailing yachts, lighter and lighter, the trend seems to be to focus on design rather than size and design. I'm sure anchor manufacturers are catering to the trend - once involved, the focus is on design. However...
I read a number of these posts and I have walked plenty of jettys on marinas and I have noticed (what I regard as) insufficiently sized anchors - across the board - in the lighter yacht set. I have had a few conversations with people who have dragged and pointed at their anchor and suggested size is their problem. They wafted on about design and I came back to size. We are a 45 foot steel ketch and carry a large Delta with 80m of 10mm chain and 100m of 8-plait 16mm nylon + a 60 kg storm anchor - admiralty pattern, a large Danforth and a second 40kg admiralty pattern. Because we have a high gear carrying capacity. I have three separate rodes to use on them. While up at the Abrolhos Islands a couple of years ago we were anchored on sand with some patches of sand over shelf - a typical ground there - and watched a glass yacht about our size repeatedly dragged past us in 30 knts wind. Their anchor was one of the flash new designs but it seemed so small! I asked him on the radio if he needed a lend of an anchor for the night but he'd given up by then and was moving. He said the anchor he has was all he can fit on his bow holder. Sure our large Delta is the size you see on the 60 foot stinkies. But my point is have we got too far down the supa-light yacht road where they cannot carry adequate ground tackle?

[foggysail]

Originally Posted by Velella99

One thing I hear little of is the size of the anchor that is used. With modern sailing yachts, lighter and lighter, the trend seems to be to focus on design rather than size and design. I'm sure anchor manufacturers are catering to the trend - once involved, the focus is on design. However...
I read a number of these posts and I have walked plenty of jettys on marinas and I have noticed (what I regard as) insufficiently sized anchors - across the board - in the lighter yacht set. I have had a few conversations with people who have dragged and pointed at their anchor and suggested size is their problem. They wafted on about design and I came back to size. We are a 45 foot steel ketch and carry a large Delta with 80m of 10mm chain and 100m of 8-plait 16mm nylon + a 60 kg storm anchor - admiralty pattern, a large Danforth and a second 40kg admiralty pattern. Because we have a high gear carrying capacity. I have three separate rodes to use on them. While up at the Abrolhos Islands a couple of years ago we were anchored on sand with some patches of sand over shelf - a typical ground there - and watched a glass yacht about our size repeatedly dragged past us in 30 knts wind. Their anchor was one of the flash new designs but it seemed so small! I asked him on the radio if he needed a lend of an anchor for the night but he'd given up by then and was moving. He said the anchor he has was all he can fit on his bow holder. Sure our large Delta is the size you see on the 60 foot stinkies. But my point is have we got too far down the supa-light yacht road where they cannot carry adequate ground tackle?

I have no love for the Delta, even have a very much like new 88# retired in my basement.Evey time I used them they plowed! Sure, they appeared to be well set but over time, they slowly plowed. I now have an 80# Maxwell Supreme along with a huge Fortress. Nice to be able to sleep at night