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Old 27-05-2014, 06:34   #91
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Re: Photos of Anchors Setting.

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Originally Posted by noelex 77 View Post
The second photo shows the distance taken to set. This was considerably longer than normal for this anchor, indicating the anchor was, understandably, having a tough time, but the distance is quite comparable to the normal length taken by many good anchors in the sort of substrate at a normal scope.

This was not a very scientific test, there was no control and only one trial, but it was a very impressive performance. The anchor holding full reverse and remaining buried with the chain pulled up at almost 30 degrees off the horizontal. This is quite amazing to watch.
I will do some more trials and report.

Note: At these very short scopes chain catenary and even the grip of chain on the bottom can play big role. With full reverse at 2:1 there is virtually no sag in the chain, but the small amount of catenary at the start of the setting does help the anchor get an initial bite. This was at 7m and I would expect the result to be slightly better at deeper depths and worse when shallow. My chain is on the light side for my boat (10mm G7) making the anchors job a little harder. The Mantus is oversized, which helps slightly with setting and considerably with holding power.

Setting at these very short scopes is one area where a kellet can be of benefit. Another good trick if the anchorage allows this is to set the anchor at longer scope (say 5:1) and then shorten the rode to 2:1. This will at least set an anchor that refuses to bite at 2:1. It also helps to only very slowly increase the force when setting. None of these methods were employed for this set.

Sorry about the video failure. Hopefully the still shots of the final result are some compensation. At the same time I did also take a underwater video, that worked, of the Mantus setting at a more conventional, but still challenging 3:1. I will post this when I can get a quick enough internet connection. Even with the chain angle at 3:1 I think this video might help convince people how catenary disappears as the force increases (in this case mainly from the engine) and how a good anchor can still dive down with the shank pulled up at a considerable angle.
Very interesting photos and a very well result, really.
I just wonder if such set Mantus would be able to rotate with the windshift, not breaking out..?..
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Old 28-05-2014, 02:10   #92
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Re: Photos of Anchors Setting.

At last we are in an anchorage that is not too deep or too murky to see the anchor, the first since we arrived in Turkey a couple of weeks ago.

This is our 45kg galvanised Spade on an 11mm chain. We were in a fairly tight spot and dropped in 9m so only put out 3:1 (we prefer 4:1). The bottom was soft sand. You can see that the anchor ploughed a short furrow and built a sand bank in front of the flukes before burying completely.
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Old 28-05-2014, 04:39   #93
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Re: Photos of Anchors Setting.

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Originally Posted by NornaBiron View Post
At last we are in an anchorage that is not too deep or too murky to see the anchor, the first since we arrived in Turkey a couple of weeks ago.

This is our 45kg galvanised Spade on an 11mm chain. We were in a fairly tight spot and dropped in 9m so only put out 3:1 (we prefer 4:1). The bottom was soft sand. You can see that the anchor ploughed a short furrow and built a sand bank in front of the flukes before burying completely.

Another proof for Spade being really good anchor
By the way, what is the dsisplacement (in cruising conditions) of Your boat?
I just assume it can be a bit heavier (being steel built) than my 16 meters GRP boat

Best regards

Tomasz
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Old 28-05-2014, 06:46   #94
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Re: Photos of Anchors Setting.

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I just wonder if such set Mantus would be able to rotate with the windshift, not breaking out..?..
At 2:1 all bets are off and it certainly merits careful watching with a wind shift. The anchor alarm can be set to wake you to a wind shift (it is not just a dragging warning, depending on how it is set) and this would be sensible if anchoring on a short scope like this.

For what its worth, I sat the rest of the day at 2:1. That night I let out a bit more scope (my wife and I were going ashore for a romantic evening fire and dinner on the beach and there is no point leaving the boat sitting at 2:1 unnecessarily). I felt the set was OK and did not reset the anchor (it would have buried better at the longer scope if I had fired up the engine).

I photographed the anchor this morning and it was unchanged.
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Old 28-05-2014, 06:50   #95
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Re: Photos of Anchors Setting.

Re: Photos of Anchors Setting.
Quote:
Originally Posted by NornaBiron
At last we are in an anchorage that is not too deep or too murky to see the anchor, the first since we arrived in Turkey a couple of weeks ago.

This is our 45kg galvanised Spade on an 11mm chain. We were in a fairly tight spot and dropped in 9m so only put out 3:1 (we prefer 4:1). The bottom was soft sand. You can see that the anchor ploughed a short furrow and built a sand bank in front of the flukes before burying completely.



Another proof for Spade being really good anchor
By the way, what is the dsisplacement (in cruising conditions) of Your boat?
I just assume it can be a bit heavier (being steel built) than my 16 meters GRP boat

Best regards

Tomasz

Rex Wrote:

You are correct Tomasz, Spade is by far the best concave anchor on the market, no roll bar to pack, no mud ball, its a no brainer.

All roll bar anchors shown in those photos I would call poorley set when you compare them to the spade photos, and yes they are as good a conditions you will find for any anchor.

I think Knoelex will have to park his rocna as it is clear the Mantus is far superior to setting than his rocna, but agaian I would be cautios with either design with a shallow set as demonsrtrated, mind you it is every photo, unlike the great sets you see several times from the spade.

Further the large roll bars sticking up could easily be snagged with chain, very problematic could be the little float sticking up of the roll bar should it lash itself around the anchor chain in a change of wind or tide.

Regards Rex
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Old 28-05-2014, 09:41   #96
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Re: Photos of Anchors Setting.

Another anchorage and another great set (4:1 in 8m).
If not for the roll bar, there would not be much to see.
This was a slightly different substrate with a lot of weed and rock around, but I managed to find this spot which is good sand.

The anchor has set quickly, rotated completely level and buried so the shank is barely visible. Another excellent performance.
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Old 28-05-2014, 11:09   #97
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Re: Photos of Anchors Setting.

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Originally Posted by DoubleWhisky View Post
Another proof for Spade being really good anchor
By the way, what is the dsisplacement (in cruising conditions) of Your boat?
I just assume it can be a bit heavier (being steel built) than my 16 meters GRP boat

Best regards

Tomasz
Hi Tomasz, our registered gross tonnage is 30 tonnes, she's a heavy girl! We've probably added another couple of tonnes with updates/extras and moving on board.
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Old 28-05-2014, 11:19   #98
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Re: Photos of Anchors Setting.

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Re: Photos of Anchors Setting.
Quote:
Originally Posted by NornaBiron [URL="http://www.cruisersforum.com/forums/f118/photos-of-anchors-setting-126073-7.html#post1551399"][IMG]http://www.cruisersforum.com/forums/images/buttons/viewpost.gif[/IMG

Rex Wrote:

You are correct Tomasz, Spade is by far the best concave anchor on the market, no roll bar to pack, no mud ball, its a no brainer.

All roll bar anchors shown in those photos I would call poorley set when you compare them to the spade photos, and yes they are as good a conditions you will find for any anchor.



Regards Rex
We moved anchorages today and arrived too late to take a decent photo of the Spade, we'll take one and post it tomorrow. We dropped in 6m with 5:1 scope (we're the only ones here) and set the anchor using our usual technique (usual since noelex convinced us to change!). We initially held but when putting on approx 3/4 power astern we dragged the anchor about 50 metres. The bottom looks like muddy sand, the anchor is completely buried. There is no wind forecast for tonight and we are well sheltered so we'll set the wind alarm at a lower than usual level and investigate further tomorrow when there is more light.
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Old 28-05-2014, 11:21   #99
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Re: Photos of Anchors Setting.

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Hi Tomasz, our registered gross tonnage is 30 tonnes, she's a heavy girl! We've probably added another couple of tonnes with updates/extras and moving on board.
[PEDANTIC MODE] erm, registered tonnage has no relation to vessel displacement or weight but is a dimensional measurement calculation more related to potential or theoretical cargo capacity. Our last UK sailboat weighed (displaced about 9 tons yet was about 15 tons registered tonngage,[/PEDANTIC MODE]
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Old 28-05-2014, 11:27   #100
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Re: Photos of Anchors Setting.

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[PEDANTIC MODE] erm, registered tonnage has no relation to vessel displacement or weight but is a dimensional measurement calculation more related to potential or theoretical cargo capacity. Our last UK sailboat weighed (displaced about 9 tons yet was about 15 tons registered tonngage,[/PEDANTIC MODE]
Sorry, I got my terms confused - Norna does, however, weigh in at 29 tonnes unladen.
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Old 28-05-2014, 11:44   #101
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Re: Photos of Anchors Setting.

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Sorry, I got my terms confused - Norna does, however, weigh in at 29 tonnes unladen.
I shouldn't be so picky but some do confuse especially when arguing about heavy/traditional beats modern lightweight Our live aboard trawler we sold last year weighed in at 25 tonnes which was a revelation after a 9tonne cruser/racer, she had more effective sail area too it seemed than the sailboat did when docking in a crosswind, our current Benneteau even with her keel still attached weighs in at 8.5 tons (dry weight Benny France figure) with I think 14 tons registered. we have however added a 10ft RIB, with a 10hp outboard in davits, addtional 200ft of 3/8 chain, a new 45lb Delta anchor as well as the original puny 33lb polished S/S claw with 20ft of S/S chain, not to mention the fully packed toolboxes and spares etc.

PS I would have liked a Spade but they cost more than the boat does over here in the USA so went to a Delta like we had and used very successfully for years in the UK/France
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Old 28-05-2014, 12:07   #102
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Re: Photos of Anchors Setting.

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Originally Posted by NornaBiron View Post
Hi Tomasz, our registered gross tonnage is 30 tonnes, she's a heavy girl! We've probably added another couple of tonnes with updates/extras and moving on board.
Hello
Our displacement is something about 26 tons in cruising mode, full tanks, so probably about 6 tons difference. No wonder You do need 45 kg anchor. Do You feel it is adequate in all conditions?
I'm doing well with my 40 kg Rocna, but soemtime I have a feeling that... You know... Bigger is Better

Cheers,

Tomasz
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Old 28-05-2014, 12:30   #103
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Re: Photos of Anchors Setting.

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Another anchorage and another great set (4:1 in 8m).
If not for the roll bar, there would not be much to see.
This was a slightly different substrate with a lot of weed and rock around, but I managed to find this spot which is good sand.
Just because of the bottom I would be guessing that You just moved to the northern bay - necessary to look well for the place to set an anchor properly...

Anyway - nice result!

I'm trying to figure out what is the reason for Your small float attached to the anchor?

Best regards

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Old 29-05-2014, 05:33   #104
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Re: Photos of Anchors Setting.

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We initially held but when putting on approx 3/4 power astern we dragged the anchor about 50 metres. .

The steel Spade is an excellent anchor and I think you will find this is an isolated incident.

The most common cause is a bit of debris trapped under the anchor, or around the toe. With my previous Rocna it would set and hold full reverse (providing normal scope and a reasonable bottom) first time nearly all of the time. (Maybe 95%?). For the 5% where it didnt hold full reverse I usually dive and try and find the cause. The drag marks can usually be found. At the end of the drag look for some debris. I have seen old sails, towels and even once a tree!

Someone recently told us their anchor would not set and when they pulled it to the surface they found there was an old fashioned ring pull from a beer can over the tip. Even this was enough to inhibit the proper set.

In other cases you find the bottom is not what you thought it was. A thin layer of sand over rock is the most common problem. The sand looks like a great substrate from the surface, but the anchor cannot bury.

In some cases there is no explanation (although some of these will be debris that cannot be identified)

My final comment is that your boat with its variable pitch propellor can develop much more reverse thrust than most yachts. This is great for setting the anchor on most occasions, but at 3/4 revs you are generating more force that I can at full reverse.

Let us know if you find the cause.
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Old 29-05-2014, 06:13   #105
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Re: Photos of Anchors Setting.

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I'm trying to figure out what is the reason for Your small float attached to the anchor?
The main purpose of the short underwater float is so the anchor can be more readily seen underwater.

This is especially helpful in anchors that are not very "tall" like the Danforth. With this sort of anchor there is very little projection above the fluke. So once the fluke is buried the anchor disappears. The roll bar on the Mantus sticks acts as marker, so it is a little less necessary, but the anchor can still completely disappear following some force in soft substrates or tall weed. The amount of rope showing gives an indication of the depth of bury.

If the anchor ever gets fouled (such as under a mooring) it is a good attachment point to attach a line to pull the anchor out backwards. If the anchor is buried it can be quite hard when diving to get a line through any of the normal attachment points.
The height also reduces the free diving distance needed to get down to attach the line.

It is low enough that it will never foul a prop etc (if you anchor in very shallow water you can tie it back with a cable tie).
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