iapetus
Active Member
The guy was reversing at 3000 RPM... :encouragement:
The typical planning boat does 15-20 knots then, no wonder why the Rocna wouldn't reset.
Anchor setting technique
- Thread starter PEJ
- Start date
The guy was reversing at 3000 RPM... :encouragement:
The typical planning boat does 15-20 knots then, no wonder why the Rocna wouldn't reset.
BruceK
Well-Known Member
I dont dispute it is a brilliant anchor. Just that the manufacturers methodology seems well placed when seen against a real world test. (only one of many mind you and I haven't seen any others displaying the trait shown in the vid)
Hurricane
Well-Known Member
That explains a lot
Last summer we had a friend swimming when we arrived.
There was a massive area of sand to play with so we didn't put much chain out.
The Rocna didn't set.
Our friend was watching with a mask and snorkel - he said let out another 10m and try again.
That was it - it went straight in.
So, I think the angle is critical.
Thats why I now let more out than I need and wind in a little when it is set.
RupertW
Well-Known Member
If the Rocna bits about a couple of hours to set before you can put on real tension are true then that's decided me against a Rocna when I upgrade.
If I'm anchoring around dusk I want to be sure the ground is good enough to anchor in and sleep through a squall, and have time to move if the ground is wrong and the anchor doesn't set when a significant bit of tension (to mimic the squall) is put onto it. So a 5 second set is needed not a 2 hour one. I can't really believe Rocnas are that hopeless.
If I'm anchoring around dusk I want to be sure the ground is good enough to anchor in and sleep through a squall, and have time to move if the ground is wrong and the anchor doesn't set when a significant bit of tension (to mimic the squall) is put onto it. So a 5 second set is needed not a 2 hour one. I can't really believe Rocnas are that hopeless.
BruceK
Well-Known Member
Nigelpickin
Well-Known Member
I see what you mean but with enough rode you would be fine to let the prevailing condition do the work for you. It’s tempting to give it a good tug but far better to let it work it’s way in over time. It does not seem to drag during the setting process as long as the chain is deployed at at least 5:1
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Deleted User YDKXO
Guest
I can certainly concur with what the testing of the Bruce and Delta anchors demonstrated in that video. Ferrettis always come with Bruce anchors fitted as standard so we have had quite a lot of experience with them, both the original sizes fitted and heavier sizes which I retrofitted. They set and held very well in clay but in sand they would often appear to set but then skip so that you were never sure if they were set. Then in weedy bottoms they were downright useless because they just couldnt get a bite. The Delta was a better all round anchor IMHO but as the video suggests it doesnt have enough blade area to hold in soft sand. We had a couple of scary experiences in windy conditions when the Delta appeared to hold and then started dragging after an hour or two and that was with the big 60kg Delta. We swapped that for a 55kg Rocna and as I say, its never failed to set and never dragged in 2 seasons. We have had some windy nights at anchor in the last 2 seasons although, to be fair, we've never had to anchor in a gale so until that happens the jury is still slightly out. The only downside of the Rocna is that it is an ugly old piece of scaffolding which certainly wont impress your neighbours in the marina and in our case, the Rocna is so wide that it sometimes chafes the bow lines
BruceK
Well-Known Member
The Bruce will skip and reset as you describe. However reset it does. For me the big pro with the Bruce is it's reputation for not breaking out during wind and tide changes over a 360 degree range and that it can tolerate a relatively short scope. I know it shows the lowest holding figures however they have always proved enough in some fairly demanding conditions I've had to anchor in. And thats what bugs me, because all I read I want to rush out and buy a new age anchor. Yet paradoxically when I have seen anchor failure, it has been with a new age anchor. (Delta's in these instances)
Edit: I have a 15kg Delta as a front door ornament. The owner of one of the dragging episodes gave it to me out of disgust. I cant say I blame him, he suffered quite some damage to an outdrive as a consequence
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Deleted User YDKXO
Guest
What do you mean by fail? Structural failure or dragging? Rocna certainly did go through a well publicised period when a few of their products failed structurally after production was moved to China but AFAIK that is now in the past. Look I can only report my own experience and I'm the first to admit that I'm no expert on anchors or anchoring
BruceK
Well-Known Member
Drag and bend
MapisM
Well-Known Member
You mean drag OR bend, dontcha?
I can imagine bending an anchor after it gets completely stuck (like under a rock), and the boat pulls it sideways in strong wind.
But I can't physically figure how an anchor can be bent while dragging...
BruceK
Well-Known Member
The exact details I cannot be sure of. What I can say is we took shelter when some unforecast big rollers scuppered our plans. The boat in question struggled to set anchor. Where the anchor landed I am not sure but it was in Friars Bay on the Menai and that has a mixture of mud and large shingle plus rock. To complicate matters there is a sudden drop off into the channel. Cut a long story short, of the 7 boats on this outing the two that dragged was a yottie on a CQR and him on the Delta. He narrowly missed me and after bending his drive and H bracket I had to take him in tow until the RNLI could take over. His anchor had bent at the tip and shank.
Another instance saw a Delta take 13 attempts in sand to get purchase against a 4knt current.
A final instance saw a Delta drag on a 3 to 1 scope. It was in the wee hours of the morning and I had to wake the owner up as he dragged past me to the mouth of Caernafon bar. Apparently this was the second instance. The first left him clinging to a channel buoy in 2m breaking waves before being washed up above the spring HW line for a number of weeks before he could refloat.
Another instance saw a Delta take 13 attempts in sand to get purchase against a 4knt current.
A final instance saw a Delta drag on a 3 to 1 scope. It was in the wee hours of the morning and I had to wake the owner up as he dragged past me to the mouth of Caernafon bar. Apparently this was the second instance. The first left him clinging to a channel buoy in 2m breaking waves before being washed up above the spring HW line for a number of weeks before he could refloat.
RupertW
Well-Known Member
But that is so unsafe as a technique (well it will fail sometimes) - for me the purpose of digging in is to test that the ground will hold you in an overnight squall or if one hits when you are ashore. Examples when we have set firmly in slow astern but dragged as soon as a little more throttle was applied include a very thick weedy bottom, catching a large bin bag, and sand six inches deep over flat smooth rock.
If we had let nature take its course then a blow later would sent us wandering.
Nigelpickin
Well-Known Member
Fair enough and in a blow or on unknown bed I’d also be pulling backwards and checking regardless but 2 or 3 hours before sundown on sand or mud in good conditions I’d not bother to pull on the anchors too much - the drag will catch the anchor imho.
vas
Well-Known Member
Thanks for the report. This is a risk.
In my case the float and rope are fairly small and I don't think it has much impact on the anchor setting even if caught underneath, but your experience is interesting. If you free fall the anchor, attaching the float onto a weak clip on the pulpit (such as a clothes peg) ensures the float drops second so it remains above the anchor.
This is the idea, although the wide angle of the camera lens makes the float look larger. It is only about one and half inches long:
sorry noelex, mine is 10CM in dia!!!
yours is the ones they use in fishing nets probably, will try it.
We use one of these when there is danger of rocks:-
https://www.swi-tec.us/ankerundbojen/30-self-adjusting-anchor-buoy.html
Recovering is a bit of a faf so I've made a loop of floating rope so that it can easily be picked up with a boat hook.
This is their amusing little promotion video
You can just see it floating in front of us in this pic
However, my main concern is stern-to mooring in busy harbours with other boats next to you, possibly permanent moorings on the seabed and all that.
I've seen plenty of times people struggling to lift their anchor which is tangled to boats nextdoor (or opposite as in Skiathos harbour!) so what Mike shows is interesting, although rather expensive!
Is there a cheapskate version of it other than having someone on the bow telling them the depth and getting the length right with a simple buoy?
Hm, edited to say that this video is probably an easy way to do it on the cheap with a reasonable length of rope. Anyone tried it?
https://www.youtube.com/watch?v=dvD7C3HukrM
cheers
V.
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noelex
Well-Known Member
Ah yes, that would certainly affect the anchor if caught undeneath.
sorry noelex, mine is 10CM in dia!!!
If rigging one of the short underwater floats (as opposed to an anchor float that is designed to sit on the surface), the float only has to just overcome the negative buoyancy of the line, so it can be very small.
Some cruisers simply use a positively buoyant line without a float at all. I think Dyneema may be good in this application, although it may no have quite enough flotation.
This octopus obviously approved of (actually I think he was in love
with) our underwater anchor float:
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Boatbore
Well-Known Member
Great pic
Boatbore
Well-Known Member
Reading this thread, I would observe that broadly we are all laying out chain and using some sort of pull to make sure we are set. Even JFM’s technique does that, mostly because his boat weighs 40 tonnes or so, so whe. It does take up on the chain it sets the anchor. So then the variations in the thread only really appear to be through different choices of anchor, and of course different conditions........ all of which makes sense. And it’s also true that there is a huge difference between anchoring for the night and anchoring for lunch where no one is leaving the boat or not paying attention and action can be taken easily and promptly before any disaster befalls.
Mind you none of that explains something I see very often in South of France, which is a boat laying out chain by going FORWARDS...... I can’t tell you the number of times I’ve seen that in St Tropez usually followed by an almost instant departure for the nearest beach restaurant ! I would guess the forward movement stops the chain piling up on top of the anchor, then the time necessary for the Boat to fall back and tension the chain correctly allows for the argument that some time is best for the anchor to correctly set, and I suppose they get away with it because it’s a very soft sandy bottom and provided they lay out enough chain (5 or even 6x) and in relatively shallow water (3 m) then all ends well.
Mind you none of that explains something I see very often in South of France, which is a boat laying out chain by going FORWARDS...... I can’t tell you the number of times I’ve seen that in St Tropez usually followed by an almost instant departure for the nearest beach restaurant ! I would guess the forward movement stops the chain piling up on top of the anchor, then the time necessary for the Boat to fall back and tension the chain correctly allows for the argument that some time is best for the anchor to correctly set, and I suppose they get away with it because it’s a very soft sandy bottom and provided they lay out enough chain (5 or even 6x) and in relatively shallow water (3 m) then all ends well.
vas
Well-Known Member
+1000, noelex you should sell this pic to Mantus
sailing boats by anychance? I've not seen mobos do it, but a few sailboats do it. Don't know why/how though
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Deleted User YDKXO
Guest
Yup seen that many times in the Med and not just with amateur boaters. Personally I dont think its anything other than a bit of showing off and wanting to get the whole anchoring process done as quickly as possible in order to maximise drinking time. I can't see anything but potential disasters doing it that way such as tangling the chain with your props or catching the anchor on an obstruction and pulling your anchor winch out of the foredeck
