Rocna and sticky mud.

[Kelpie]

Have to agree in all the years we had a Rocina once set we Never dragged actually last Oct we had both our 14mm snubber snap in a storm but the Rocna held fast even as we swing 380 and back again .

Have I just been unlucky?

Off the top of my head, the times we've dragged were:
1- in Fornells, Menorca. Anchor was on seagrass (oops). 3:1 scope. Conditions were settled and it was only after diving on the anchor that I could see what the bottom really was. Decided we would move the next day, but before that happened the wind went from almost zero to 30kt from the opposite direction, and we were off at a rate of knots. I don't actually count this as a mark against the anchor, it was my fault for picking the wrong spot and then not immediately doing something about it.

2- In Pollensa, Mallorca. On supposedly sand, but with reports of patchy holding. The holding is strange there, with sparse weed and the sand has a strange consistency, breaking up in to light clods. We were on a slightly generous 3:1 and one afternoon the wind suddenly came at around 30kt from a new angle, and we dragged a short distance before holding again. Should have taken this as a warning!

3- same place a day or two later, we were hit by a big increase in speed to nearly 50kt and a large change in direction. Dragged rapidly down towards another boat, managed to get clear and re-anchor.

4- same night, same conditions and holding. Laid 6:1 scope during a lull, but dragged again once wind exceeded 40kt. Re-anchored at 10:1 and this time held firm.

(note, on these three occasions in Pollensa, we had friends anchored beside us, with a slightly larger boat and a 20kg Spade. They never moved an inch).

5- in the Mar Menor, on about a 4:1 scope in mixed mud and weed holding, we dragged slowly and reset in winds which gusted up to 45kt. Extended scope to 8:1 and did not drag again, although wind did not exceed 30kt.

We also have friends who dragged in Addaia, Menorca, with a 25kg Rocna.


I no longer have the blind faith that I one had in our Rocna. Perhaps it's my technique. Perhaps it's just a combination of poor holding and testing conditions. Anyway, I might be asking Santa for a spade...

 

[LittleSister]

West and north Scotland has many anchorages with sticky smelly mud.

Not to mention the local inhabitants!

 

[sailaboutvic]

Any anchor will drag if a combination of circumstances are put into play ,
We learned over the years Blind faith or chance when you life relie on a anchor to keep you safe isn't the answer.
I am a bit surprise at the amount of times you said you have drag , I can't comment what's going wrong and it be wrong of me to say it's your technique ,why your having so much problem with your Rocna .
On our last boat which we sold this year we had a 25kg Rocna 10 mm chain , 14.5 tons of boat ,
because of the way we mark our chain it's easier to drop 5:1 plus Christine who normally up on the bow can count almost to the a few CM how much chain was going in without looking , so in the dark she knows how much have gone out.

The time we dragged have always been while setting the anchor , once a shopping trolley came up another a fishing net we even had a football but once set we not had it dragged,
One problem we notice is some skipper drop and are afraid to put the RPM on , others if it not set the first time are so worried of on lookers they just hope for the best .
I remember once we was trying to set our in thick weed We tried it three or four times moving from spot to spot each time bringing heaps of weed up,
Some guy shout you putting too much rev on you never set it that way.
well we had to anchor way out that night before the anchor set,
we had a little blow that night , no more then 25kts all three boats dragged including Mr ( your putting too much rev on mate) .
We was pretty sure once set we be fine for the night but even so the anchor Alarm when on ever night and in any big blows we be up just incase we did start to drag .
We now using a Manson , it came with this boat and we found so far touch wood it's doing its job although where with the Rocna we anchored in almost anything that came along , the Manson as mostly been used in Mud as most of our Cruising thus year as been in the Netherlands.

By the way we sat out a 48 hours storm in Pollensa on the Rocna

 

[Mistroma]

Any anchor will drag if a combination of circumstances are put into play ,
We learned over the years Blind faith or chance when you life relie on a anchor to keep you safe isn't the answer.
I am a bit surprise at the amount of times you said you have drag , I can't comment what's going wrong and it be wrong of me to say it's your technique ,why your having so much problem with your Rocna .
On our last boat which we sold this year we had a 25kg Rocna 10 mm chain , 14.5 tons of boat ,
because of the way we mark our chain it's easier to drop 5:1 plus Christine who normally up on the bow can count almost to the a few CM how much chain was going in without looking , so in the dark she knows how much have gone out.

The time we dragged have always been while setting the anchor , once a shopping trolley came up another a fishing net we even had a football but once set we not had it dragged,
One problem we notice is some skipper drop and are afraid to put the RPM on , others if it not set the first time are so worried of on lookers they just hope for the best .
I remember once we was trying to set our in thick weed We tried it three or four times moving from spot to spot each time bringing heaps of weed up,
Some guy shout you putting too much rev on you never set it that way.
well we had to anchor way out that night before the anchor set,
we had a little blow that night , no more then 25kts all three boats dragged including Mr ( your putting too much rev on mate) .
We was pretty sure once set we be fine for the night but even so the anchor Alarm when on ever night and in any big blows we be up just incase we did start to drag .
We now using a Manson , it came with this boat and we found so far touch wood it's doing its job although where with the Rocna we anchored in almost anything that came along , the Manson as mostly been used in Mud as most of our Cruising thus year as been in the Netherlands.

By the way we sat out a 48 hours storm in Pollensa on the Rocna

Lack of revs seems pretty common with many charter boats. It's as if they are afraid it will pull the anchor out and that's exactly what I like to check. We tend to reverse while laying out the chain and let it tension up a couple of times. After the desired scope is out we increase revs. steadily from 1,000, 1,200, 1,500, 1800, 2200, 2,400 and 2600. We usually stop around 2,200 and use higher revs if wind expected. Max rpm is 3,000 on our engine.

I've had the anchor pull out suddenly at 2,400 or above a couple of times and it came up with a big ball of weed or a large rock stuck in the claw. The Bruce doesn't like weed or rocks sized to fit nicely into the claws.

Our normal routine is to mark a MOB point on the plotter as the anchor touches the bottom. I put the cursor on the mark as we reverse and it's easy to see if we are holding position. I usually look for a decent transit as well but distance from the MOB mark is very useful. It also comes in handy when the wind changes as I know where the anchor is as we swing around. Pretty useful to tell a charter boat that your anchor is 10m off your stern as he starts to drop his level with your mast.

 

[Kelpie]

@sailaboutvic
Did you dive on your anchor at Pollensa? And if so, how well buried was it? Ours seemed to bulldoze a mound in front of itself but not keep digging deeper. The roll bar always remained visible.
We also have 10mm chain, and a smaller and lighter Moody than yours.

 

[Mistroma]

@sailaboutvic
Did you dive on your anchor at Pollensa? And if so, how well buried was it? Ours seemed to bulldoze a mound in front of itself but not keep digging deeper. The roll bar always remained visible.
We also have 10mm chain, and a smaller and lighter Moody than yours.

I never dive just to check the anchor but did check our anchor at Pollensa. We were anchored about a mile from town, out around Punta de la Avancada. The anchor seemed to be holding well but we dragged during the night in very strong gusts. I went swimming the next day and decided to pull myself down the chain and swim around. I think the depth was only 3-4m but was surprised to find several large holes about 10-15m diameter and about 2m or more deep. The bottom was a bit crumbly and I think our anchor must have been close to a hole the previous night. The edge probably collapsed and the anchor fell into a hole, dragged across the bottom and up the other side. It probably didn't catch the top lip as it would just crumble away.

 

[Neeves]

A good snubber will make an average anchor into something more reliable.

It will take out the snatches and surges. It is seldom a lack of hold but the constant movement of the yacht, back and forth, side to side. Smooth out the variations with a snubber the anchor has a better chance.

Think of you mixing concrete - get it of the right consistency - now twiddle a towel in the concrete - the concrete turns to liquid. - what do you thing the seabed is like within which your constantly twitching anchor is embedded. A decent snubber will smooth out the twitches, like the suspension, tyres, foam in the seats smooths out the ride in your car.

A 2m piece of rope is not a snubber.

You need at least a boat length, thin, piece of nylon as a snubber - something that gives you stretch. You need the ability to extend the snubber when the wind gets up or be able to add a storm snubber. If your snubber is too beefy - it will not stretch, enough.

When you rode looks straight it has no snubbing ability left.

Jonathan

 

[Neeves]

If your anchor has the propensity to collect and make more dense the mud it collects then as your anchor sets its shape changes. The clod of mud compacts and your set anchor will no longer dive more deeply. Your anchor is essentially a clod of mud supported by a fluke and roll bar. That same anchor will dive more deeply in nice clean sand (that is usually the seabed in which the anchor is tested).

The much maligned Epsilon has a convexity in the centre of its concave fluke which I suspect is there to ensure a clod of mud does not densify but is swept aside - I don't know I'm guessing. But convex anchors, Kobra, Excel don't collect a clod of mud but dive and sweep the seabed either side of the fluke (which is why they tend to be retrieved clean). Its about design not weight (as an aluminium Excel performs similarly to its steel brother).


But interesting - we have some people on this thread saying a Bruce does not clog with mud and we have other people saying a Bruce does clog. Maybe the seabeds are different . My very limited experience is - they clog.

Jonathan

 

[sailaboutvic]

@Mistroma you just hit the nail on the head , just as you do we do the same , we keep increasing the rev , I believe if my then 50hp will pull the anchor out then when we have a good blow we have no chance .
We experience the same as you did , at rev off 2000 rpm all good and you start to think it's set then add a bit more and away you go , only to find that the anchor was holding onto a nic e lump of weed.
If we didn't add that bit more rev to 2200 rpm we would had when to bed thinking we safely anchored and a over night blow would had seen us dragging especially as we would had pulled most of that weed out while trying to set .
Next morning the conversation will be ( bloody Rocna is useless ) when really it wasn't the anchor .

Jonathan will remember this , once in the south of France we anchored and did as we always did and in top rev I had this feeling all wasn't right , it felt like there was a very slight drag , first I thought it was my imagination and only after I signal for Christine to finish the job putting the snubbers on and she returned she if I was sure it set ok bacause it didn't feel right ,
So after a cool drink we decided to haul up and check as it was forecaste for 30 to 35 kts that night , we haul up and just as most of the chain was in the breaker tip , nothing unusual, the bloody thing would do it now and then , we set and try again ,
In the end the anchor came up with an old fisherman spider anchor. part was through the hoop.
It took some time to untangle the mess .
The blow did arrive but a lot stronger then expected , I don't know if we didn't check on the anchor that day if we would had dragged or not but if we did start to drag and needed to haul up quickly we would had one heck of a problem.

 

[Kelpie]

Sounds like my snubber is a bit undersized... it's about half a boat length, 12mm three strand nylon.

I've noticed a lot of people use a bridle snubber, presumably to help reduce veering?

 

[roaringgirl]

Any anchor will drag if a combination of circumstances are put into play ,
We learned over the years Blind faith or chance when you life relie on a anchor to keep you safe isn't the answer.
I am a bit surprise at the amount of times you said you have drag , I can't comment what's going wrong and it be wrong of me to say it's your technique ,why your having so much problem with your Rocna .
On our last boat which we sold this year we had a 25kg Rocna 10 mm chain , 14.5 tons of boat ,
because of the way we mark our chain it's easier to drop 5:1 plus Christine who normally up on the bow can count almost to the a few CM how much chain was going in without looking , so in the dark she knows how much have gone out.

The time we dragged have always been while setting the anchor , once a shopping trolley came up another a fishing net we even had a football but once set we not had it dragged,
One problem we notice is some skipper drop and are afraid to put the RPM on , others if it not set the first time are so worried of on lookers they just hope for the best .
I remember once we was trying to set our in thick weed We tried it three or four times moving from spot to spot each time bringing heaps of weed up,
Some guy shout you putting too much rev on you never set it that way.
well we had to anchor way out that night before the anchor set,
we had a little blow that night , no more then 25kts all three boats dragged including Mr ( your putting too much rev on mate) .
We was pretty sure once set we be fine for the night but even so the anchor Alarm when on ever night and in any big blows we be up just incase we did start to drag .
We now using a Manson , it came with this boat and we found so far touch wood it's doing its job although where with the Rocna we anchored in almost anything that came along , the Manson as mostly been used in Mud as most of our Cruising thus year as been in the Netherlands.

By the way we sat out a 48 hours storm in Pollensa on the Rocna

Rocna says you need 1:5; 1:3 is their minimum.

Re: backing down - I always check the set of the anchor by backing down *hard*, but only after I've waited for the wind to gently set it first. I've found it's possible to pull it out before it's properly set if I'm impatient with the motor.

 

[sailaboutvic]

@sailaboutvic
Did you dive on your anchor at Pollensa? And if so, how well buried was it? Ours seemed to bulldoze a mound in front of itself but not keep digging deeper. The roll bar always remained visible.
We also have 10mm chain, and a smaller and lighter Moody than yours.

You asking some think now , it must had been over 10 years ago , all I can say is we would had set it as we always do and once we reach 2200/2400 rpm it stays at that rpm for a bit .
I don't as a rule dive on my anchor , there been times when I or my co skipper are swimmer and may put have a mask on .
I never know how deep my anchor is or if the hoop is showing or not.
there been hundreads of times when we arrived in the dark or in a blow and personally I feel you just have to have a feel of how things are as you won't be diving in the dark or when it's blowing , well I won't be anyway.
I'm am very surprised how many times in such a short time you said you dragged and please don't take this the wrong was but maybe it's something isn't quite right .
Many many moons again I was based in Kos marina , it had just open , I was teaching and skipper chartering on my own boat to help pay for the up keeping of my boat .
There been many time when owners wife's have ask me if I would go out with then to practice anchoring because they where afraid to anchor over night , most where very competent sailors but anchoring just wasn't there thing.
As I said it's normally the wife , the guys wasn't going to admit there where doing some thing wrong ,
Just by going out and letting then drop there hook a few times it very quickly came to light what their problem was a combination of things.
Most common was not dropping enough chain , dropping too quickly so it piled up, going astern too fast, not given the anchor a few second to settle before setting and off course the biggest sin of all not putting enough Rev on at the right time .
Now all this sound as if I'm some kind of expert, let me just say there been time we got it wrong and had to anchor several times before we was happy to, so an expert I am not .
when I had my accident last Oct we made some real bad mistakes.
The forecaster was for light winds and no thunderstorms in sight,
first mistake believing the forscaster was 100% right.
Next we arrived and found some old friends there so we anchor quickly and didn't drop the amount of chain we normally only because they where already in their dinghy with cold beers , we thought we finish the job later .
As we only anchored temporary only one set of snubber when on a second is normally used by the windlass in case we needed it and it was also as a stopper in case something happen to the snubber .
cold beer when on to snacks then we decided all to eat on board and more drinks , midnight flat claim clear sky's with our dinghy left in the water something we ever hardly do we went to bed without checking or finishing the job .
0400 all hell let loose thunderstorms arrive we ended up on a lee shore with winds touching 60kts how the anchor held is any body guess although we had a 5:1 scope we didn't have the snubber out to full length, then when they both snapped ( two 14mm in a bridal ) our second snubber wasn't it place to stop the chain from jumping off the windlass , mistakes can easily be made , even so I was anony with myself for making stupid misstake, when we should had known better .

 

[sailaboutvic]

Rocna says you need 1:5; 1:3 is their minimum.

Re: backing down - I always check the set of the anchor by backing down *hard*, but only after I've waited for the wind to gently set it first. I've found it's possible to pull it out before it's properly set if I'm impatient with the motor.

5:1 is our min we know to use 7:1 is we know we in for a big blow and even more as long as we got room and we alway do because if there a blow we move away from any boats near us ,( not always possible) and still there been times when boats have drag on us .
Agree but gentle going back in astern is the same as letting the wind take up the slack , there been may days when there been no wind ,
I also agree you should leave it a few seconds once it bit before start putting the Rev on.

 

[sailaboutvic]

Sounds like my snubber is a bit undersized... it's about half a boat length, 12mm three strand nylon.

I've noticed a lot of people use a bridle snubber, presumably to help reduce veering?

Bridle is what we use on our main snubber then we have a single second snubber you could call it an emergency stopper close to the wind lass .
We also use this first when setting the anchor , once set the bridle goes on .

 

[Neeves]

If you rig a bridle then the 'V' will reduce veering - but

If you have much of the bridle forward you will narrow the 'V' to the point it works as a single snubber Not as a 'V bridle. If you were to have the chain hook, say 1m forward of the bow roller - so just outboard - then the 'V' will be a large angle. If you commence the bridle at the bow - it will be too short - and have no elasticity.

Now....

If you commence the bridle at the transom, running up each side deck, you have a deck length for elasticity and only a short portion forward - giving you a wide angle bridle which will manage the yaws. You need to watch for abrasion where you go out board.

An advantage of having the chain hook (bridle plate?) just forward of the bow - if the forecast becomes inaccurate and the weather is now taxing you can add another snubber, immediately aft of the original and deploy the second snubber (adding to the bridle) without the need to deploy much extra chain (there maybe other yachts close aft). Simply add another snubber, take to a sheet winch - take in some tension.

You now have a snubber and bridle - just get the balance right, the new snubber only taking the big gusts.

Snubbers and bridles are consumables, like sails and halyards. If they don't wear (fail) they are too robust, too thick, too short. They need to stretch and unfortunately life reduces with the number and size of stretch cycles - we carry spares.

We are a 38' x 7t cat, 22'6" beam - we have the windage of a 45' Bav. We were using 12mm climbing rope but have downsized to 10mm climbing rope. Our bridle 'starts' at the transom.


If you want detail of our arrangement send me an email address (PM) and I'll send a pdf, or 3 . If with this initial; contact you define your yacht - I can be more quantitative with a reply. If subsequently you need clarification I'm happy to discuss openly here - or as a series of emails. Sorry but the pdfs are too big to post here and I'm not that computer literate to compress them - and don't want particularly to post via the various file sharing opportunities.

Knowledge is of little value if it is not shared.

Jonathan

 

[asteven221]

Interesting thread. We don't anchor very much, so my experience doesn't really offer much value to this thread, other than to say that on each and every occasion we have anchored using our Manson Supreme, we have had retrieved it with a large compacted pile of mud (like concrete) stuck on it. It takes quite a while to clean, battering it with the boat hook and dipping it back in the sea. Once we had big rock wedge under the roll bar.

My instinct tells me that a ball of compacted mud making the shape of the anchor like a ball, isn't a good feature for an anchor!

 

[sailaboutvic]

Interesting thread. We don't anchor very much, so my experience doesn't really offer much value to this thread, other than to say that on each and every occasion we have anchored using our Manson Supreme, we have had retrieved it with a large compacted pile of mud (like concrete) stuck on it. It takes quite a while to clean, battering it with the boat hook and dipping it back in the sea. Once we had big rock wedge under the roll bar.

My instinct tells me that a ball of compacted mud making the shape of the anchor like a ball, isn't a good feature for an anchor!

Have to agree the six months most days we been using our Manson in very muddy sea bed our too mostly come up covered in mud but saying that we not so far had a problem with it resetting .
We might do in the future who knows .
Also the mud isn't caked on the bottom but on top and considering it been buried in thick sticky mud I'm not really that suprise.
A few weeks ago I see a SS Spade hauled up it too had mud stuck to it .

 

[mattonthesea]

I was surprised by how kelp affects our Manson. By surprised I mean up out of the bunk and motor on in less than 5 seconds! Impressed by it's quick set so far I had ommited to explain its characteristics to my partner. The night before we had anchored in Old Grimsby Sound but, given the NE gale forecast, I had decided to move more towards St Helen's Pool to give us more room to leeward, away from the shore. Although she told me that there had been a lot of weed on the anchor I hadn't realised that she had not removed it. So, around nine in the morning, with a 32kt gust, we felt it give; and we were up!

This time I think we had enough seaweed on it to feed Tresco for a week. Both a bit shaken and wet we opted for a mooring for the day. Looking behind us we saw the dinghy drifting in to Old Grimsby beach. Thank goodness we had a rope cutter. With the cockpit tent up I'd forgotten about the dinghy on a long leash.

I'd always learnt to anchor in the way Vic described above. Perhaps I'd got lazy because it always set. Whatever, since then, I've been scrupulous about testing. And I try to remember to give my partner a briefing about anything new.

PS I still shudder about it. Lots of'what ifs' and 'how would I have respondeds'.

 

[Kelpie]

Lots of food for thought.
Generally we try to get the anchor right first time. Having a very slow manual windlass encourages that!
So we aim to have it touch the bottom whimsy we are not moving, and then if the conditions are light I will feed the chain out through the hawse hole hand over hand to match the died that we are drifting back. In stronger conditions I'll use the brake on the windlass instead. I don't like to let us build up too much speed, since once I apply the brake there's a big load on the windlass.
Having veered a minimum 3:1, I'll then take a few turns around the samson post and gently take up the strain in astern, before applying around 2000rpm for a couple of minutes.
Next, I'll tie on the snubber and then veer additional chain until the load is on the snubber and the chain has a big bight of slack.

Any thoughts on my technique would be appreciated. It works 99% of the time, but in the last few weeks we've had horrible squalls touching 50kts and as I am explained above the Rocna has finally proven itself to be less than bulletproof.

 

[Poignard]

Head above parapet time!

To what extent is the CQR self-cleaning?

What I mean is, if it were to drag, would it not tend to 'wipe' off any mud as it moves rather than pick up a ball of mud?

The only time I can remember having had a significant build up on mine is when I have anchored in clay, which sticks like s**t to a blanket. Even then, it was not sufficient to cause it to drag.