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20-08-2015, 04:52
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#1741
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Moderator
Join Date: Jul 2007
Boat: Bestevaer.
Posts: 14,683
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Re: Photos of Anchors Setting
This was a Delta.
It was dropped in a small patch of light weed. It had been pulled back about five feet or so and had not yet made much of an attempt to set.
Delta anchors take a long distance to set, so no doubt it would do better given some more time. Notice it has retained the patch of weed on the fluke despite being dragged several feet over clear sand:
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20-08-2015, 07:12
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#1742
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Moderator
Join Date: Jul 2007
Boat: Bestevaer.
Posts: 14,683
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Re: Photos of Anchors Setting
From the marks left in the sand it is possible to deduce the history of an anchor's behavior, but it always a treat to see an anchor rotate "live". This is the Delta in the previous post #1741.
This was the next morning.
It will take a few posts to show the entire rotation. This is how the rotation started. The wind has reversed 180° overnight. The boat has swung around so it is now on the opposite side of the swing circle.
The chain is stretched out in the new direction. Most people imagine at this stage the anchor always rotates around. If the anchor is well set it takes a reasonable wind force for the anchor to rotate and often it will sit in position unchanged with the chain leading the wrong way.
However, this Delta was very poorly set and did not have much grip to resist the rotation. Nevertheless, it remained like this for a long time with a gradually increasing wind:
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20-08-2015, 08:19
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#1743
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Moderator
Join Date: Jul 2007
Boat: Bestevaer.
Posts: 14,683
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Re: Photos of Anchors Setting
Here the Delta has dramatically "let go". Not that it had much holding to begin with. You can see the clouds of sand given off as the the shank rapidly flips around.
This is not the sort of rotation you ideally want. An anchor that rotates rapidly like this has very little grip during the transition. Most of the time it will reset, but not always.
The Delta is not great at rotating in a controlled fashion or "shuffling". It often develops a high list when rotating and in harder substrates most of the grip is a due to the anchor heaping up substrate in front of the fluke. As the anchor rotates this effect is lost and the fluke is exposed. The anchor has to drag in the new direction to once again pile up the substrate.
However, in this case the poor performance was due to the poor set. Any anchor that is poorly set will perform like this, although the best anchors would have set more rapidly than this Delta did to begin with.
This happened during daylight hours (not even anchorholics dive at night ), but it could have just as easily happened when the crew were asleep.
The wind was only light.
I think if people knew their anchors were behaving like this they would be keener to set their anchors well and purchase models that rotate competently.
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20-08-2015, 09:53
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#1744
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Registered User
Join Date: Sep 2009
Location: Melbourne, Australia
Posts: 2,844
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Re: Photos of Anchors Setting
Quote:
Originally Posted by hoppy
Tonights anchorage...
The Vulcan dug in very quickly but as you can see, it did travel a bit under the surface. I think I gave it close to 3000rpm and it held eventually
Attachment 107583
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Last night I did a 180 turn and the wind picked up to 20 knots. In the morning I swung back to the same direction as I started. When I dived on the anchor I was disappointed to see that the anchor had not moved and there was no change to the chain marks in the 10m up to the seaweed bed. Clearly my chain held me when it was blowing 20 in the other direction. I guess 6:1 scope was too much to test the direction change
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20-08-2015, 11:52
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#1745
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Moderator
Join Date: Jul 2007
Boat: Bestevaer.
Posts: 14,683
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Re: Photos of Anchors Setting
The clouds of sand have cleared here and this is how the anchor looked. Note how the marks in the sand reveal the anchor has not "shuffled" in a controlled manner.
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20-08-2015, 22:34
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#1746
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Moderator
Join Date: Jul 2007
Boat: Bestevaer.
Posts: 14,683
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Re: Photos of Anchors Setting
This was sometime later (about 45 mins). The Delta has rotated further and is now in line with the new direction of pull.
Notice the anchor is totally unset.
The tip is sitting over an inch above the substrate!
At this stage it has not moved other than rotating, but as the anchor is totally unset it will need to move back many metres (the Delta typically takes 5-6m to set in this sort of substrate) before it has adequate grip for even modest wind.
The weed bed will be encountered before the anchor is set.
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21-08-2015, 03:14
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#1747
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Registered User
Join Date: Feb 2013
Location: Ocala FL
Boat: 1979 Bristol 35.5 CB
Posts: 1,964
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Re: Photos of Anchors Setting
It is educational to see how well anchors work even when they are not set. This final pic shows the tip of the shank dug in, maybe some weed/chain friction grip. Other than that, just the weight of the anchor/chain. Despite that, the anchor has not moved more than a few feet. The forces involved in lighter winds must be low.
Maybe I will go back to my coffee can filled with concrete for a lunch hook.
__________________
John Churchill Ocala, FL
NURDLE, 1979 Bristol 35.5 CB
Currently hauled out ashore Summerfield FL for refit
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21-08-2015, 04:30
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#1748
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cruiser
Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
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Re: Photos of Anchors Setting
Here's an education moment. Pictured is an authentic CQR on an identical Oyster 53 anchored 200 feet away from us on a hard sand bottom. It should be easy to set this anchor, but this is how it looked 12 hours after supposedly setting the anchor. I went over to our friend's boat and offered to show them how to properly set the anchor. All I could get it to do was slide sideways over the bottom for 90 feet using 90ft of chain in 10ft depth.
I'll post a picture of our Ultra 100 feet away in the same bottom in the next post.
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21-08-2015, 04:34
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#1749
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cruiser
Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
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Re: Photos of Anchors Setting
Here's our Ultra 45kg set in the same bottom 100ft away. I'd never realized how bad the Lewmar CQR we used three years ago was... until today.
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21-08-2015, 04:42
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#1750
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cruiser
Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
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Re: Photos of Anchors Setting
Here's another look at the CQR that I was very confident that I could set in the hard sand bottom.
Again.... Same boat, same depth, same amount of 12mm chain, same guy setting the anchor.... Different anchor.
Lewmar CQR vs Ultra.
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21-08-2015, 04:54
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#1751
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Moderator Emeritus
Join Date: May 2008
Location: Fort Lauderdale, FL
Boat: 48 Wauquiez Pilot Saloon
Posts: 5,975
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Re: Photos of Anchors Setting
Quote:
Originally Posted by sanibel sailor
It is educational to see how well anchors work even when they are not set. This final pic shows the tip of the shank dug in, maybe some weed/chain friction grip. Other than that, just the weight of the anchor/chain. Despite that, the anchor has not moved more than a few feet. The forces involved in lighter winds must be low.
Maybe I will go back to my coffee can filled with concrete for a lunch hook.
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I can't tell you how many of those I made with grandpa... I guess the Nam war effort was utilizing all available stainless eye bolts ...
Quote:
Originally Posted by Kenomac
Here's another look at the CQR that I was very confident that I could set in the hard sand bottom.
Again.... Same boat, same depth, same amount of 12mm chain, same guy setting the anchor.... Different anchor.
Lewmar CQR vs Ultra.
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Awesome comparison Kenomac
PS: You're almost ready for your jr mermaid apprenticeship
__________________
In the harsh marine environment, something is always in need of repair...
Mai Tai's fix everything...
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21-08-2015, 06:02
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#1752
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cruiser
Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
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Re: Photos of Anchors Setting
Quote:
Originally Posted by HappyMdRSailor
I can't tell you how many of those I made with grandpa... I guess the Nam war effort was utilizing all available stainless eye bolts ...
Awesome comparison Kenomac
PS: You're almost ready for your jr mermaid apprenticeship
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I felt a little foolish after going over their boat to show them how it's done properly, then only being able to dig a 90 ft 4 inch deep trench with the tip of their anchor.
I'd used the Same 75 pound CQR for a full season on the same boat, so I was quite confident I could get it to set.
The final decision after I showed our friends how to anchor.... They're buying a new anchor, either a Rocna or Ultra... Their decision as to which one.
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21-08-2015, 06:35
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#1753
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Moderator
Join Date: Jul 2007
Boat: Bestevaer.
Posts: 14,683
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Re: Photos of Anchors Setting
Quote:
Originally Posted by sanibel sailor
Maybe I will go back to my coffee can filled with concrete for a lunch hook.
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Is that a new generation coffee can? .
You need very little anchor performance to hold the boat in 20 knots. Even the chain alone will supply most of the grip at 10-15 knots, especially in substrates like weed. As the wind rises the force on the boat is rising rapidly (roughly as the square of the windspeed). The chain contribution becomes negligible and the anchor suddenly needs to do a lot more work.
Many people make the mistake of assuming that many successful anchoring experiences in modest winds means their anchor is working well.
By looking underwater at how anchors perform, I get very different perspective. Many anchors are performing very poorly despite achieving their fundamental objective.
The difference between good and bad anchors is not a minor, subtle difference that is difficult to pick. It is very obvious difference that is plain to see for anyone that is willing to take the time to look at anchors performing on the bottom.
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21-08-2015, 06:58
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#1754
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Registered User
Join Date: Jul 2012
Location: Somewhere in Germany
Boat: OEM, proportional
Posts: 1,437
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Re: Photos of Anchors Setting
Quote:
Originally Posted by noelex 77
The difference between good and bad anchors is not a minor, subtle difference that is difficult to pick. It is very obvious difference that is plain to see for anyone that is willing to take the time to look at anchors performing on the bottom.
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Sir, how much of the difference is in the anchors themselves, as opposed to the technique?
I realise one wouldn't set a lunch hook the same as a storm anchor, and would be well advised to have more than one anchor type for different bottoms. The opposed double-anchor technique for ensuring a good set is one thing I've picked up from this thread, for those engine-less by design or accident. Mermaid reports and ROV's won't always be available. Would it be a good idea to collate all this data in a spreadsheet and graph format to compare, Sir?
__________________
Ps 139:9-10 If I take the wings of the morning, and dwell in the uttermost parts of the sea; Even there shall thy hand lead me, and thy right hand shall hold me.
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21-08-2015, 07:37
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#1755
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cruiser
Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
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Re: Photos of Anchors Setting
Quote:
Originally Posted by micah719
Sir, how much of the difference is in the anchors themselves, as opposed to the technique?
I realise one wouldn't set a lunch hook the same as a storm anchor, and would be well advised to have more than one anchor type for different bottoms. The opposed double-anchor technique for ensuring a good set is one thing I've picked up from this thread, for those engine-less by design or accident. Mermaid reports and ROV's won't always be available. Would it be a good idea to collate all this data in a spreadsheet and graph format to compare, Sir?
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Your answer is in my previous posts made a few hours ago, when I used two different anchors on the same boat, same length of chain, same bottom, same technique.
Same everything using a CQR vs an Ultra. And I was trying just as hard using the CQR and fully expected it to grip as well as the Ultra.
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Tags
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anchor, Brittany, Bruce, Bugel, cqr, Danforth, delta, fortress, Jambo, kobra, Manson Supreme, Mantus, photo, rocna, Spade, Ultra |
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