Bouba
Well-Known Member
Mud on the sea bed isn’t the same after it’s been lifted out the water....in fact it goes from soup to mud...and is bloody difficult to shift
Rocna and sticky mud.
- Thread starter vyv_cox
- Start date
doug748
Well-Known Member
Don't know. This is worth watching:
I have been putting silicone grease on an the bearing surfaces of an Epsilon . Not the slightest idea how useful it is - but it passes the time.
.
Neeves
Well-Known Member
Interesting thread 
Anchor Resetting Tests - Practical Sailor
Prompted by Morgans Cloud comments I did the tests.
Basically, and from memory, the anchors were all set at 500kgs tension (your engine possibly offers 100kgs of tension for every 10hp, very approx, depends on prop) so the 500kg represents power set + wind. The anchors were then tripped using a 180 degree pull, we did not check the tension needed to pull out. However 500kg is indicative of wind set anchor and pull out tensions are commonly 'similar' to set tensions. If you power set with a 30hp motor, flat chat, but there is no wind and the tide changes and wind increases to 25/30 knots - you will drag..... Consequently the anchor would need a tension from wind equivalent to 500kg if it is set to 500kg. This might occur if you have tide change, turning the yacht through 180 degrees and then maybe 35 knots of wind. A change of 180 degrees will summersault your anchor - the tests on anchor set angles are in the article.
Convex anchors do not suffer 'as much' as concave anchors in retaining mud. An Excel outperforms a Rocna. The Rocna will not reset until such time it is clean of mud - it will clean the mud off as it bounces across the sea bed - but you might be on a beach before it cleans.
Interestingly Morgans Cloud made their change in recommendation as a result of beachings, I think, in the Med. They did not define the background, no vessel names, no locations. I really don't see much attention having been made to MC's comments - there are still many Rocna on bow rollers - but I have not heard of beachings nor dragging (this thread excepted) of Rocna nor Supreme recently, or since MC made their comments. Historically people were very defensive of their comments on their choice of anchor - we are becoming a bit less loyal. But being argumentative - people do end up on beaches and it maybe due to a clogged fluke, or debris on the seafloor, or a poor set or.... - when your yacht is on a beach you are not focussed at the why - but how to get the yacht back afloat.
My view has always been - Rocna is a good anchor in sand, there are issues in mud - if only the faff of cleaning them. Today there are plenty of options - you do not need to buy a Rocna (which was less true in say 2010 - there was little choice). We now have Ultra, Spade, Vulcan, Viking, Knox, Excel and Epsilon, to name but a few. The Knox was tested and if the slot between the 2 flukes was closed - if clogged. The slot allows the mud to be less adhering. Note that Viking, SARCA, Excel - all have slots or perforations (for a reason).
And - I did test - stainless brings up less mud - but it is a stiff price to pay. If you use your galvanised anchor frequently the working surface of the anchor is polished by the seabed - there is no need to buy a stainless anchor (unless you are into jewellery for your yacht). After much use your stainless anchor will be as rough as a well used galvanised anchor. Stainless is soft and will scratch easily, gal is much harder and will take longer to polish - but the polish will be more robust. Testing less frequently used anchors is a waste of time. Viking are trialling Thermal Diffusion Galvanising - which is harder than normal gal and takes a really nice polish - it looks like black stainless. Check the polish on our chain:
Many stainless anchors do not have Duplex shanks and the shank might not be dissimilar to the strength of a bendy shank anchor. Duplex stainless is very expensive, on top of the cost of 316 and the cost of polishing. Arguably you would be better buying 2 gal anchors, one convex, one concave than using stainless - you need a spare anchor, anyway.
Take care, stay safe
Jonathan
Anchor Resetting Tests - Practical Sailor
Prompted by Morgans Cloud comments I did the tests.
Basically, and from memory, the anchors were all set at 500kgs tension (your engine possibly offers 100kgs of tension for every 10hp, very approx, depends on prop) so the 500kg represents power set + wind. The anchors were then tripped using a 180 degree pull, we did not check the tension needed to pull out. However 500kg is indicative of wind set anchor and pull out tensions are commonly 'similar' to set tensions. If you power set with a 30hp motor, flat chat, but there is no wind and the tide changes and wind increases to 25/30 knots - you will drag..... Consequently the anchor would need a tension from wind equivalent to 500kg if it is set to 500kg. This might occur if you have tide change, turning the yacht through 180 degrees and then maybe 35 knots of wind. A change of 180 degrees will summersault your anchor - the tests on anchor set angles are in the article.
Convex anchors do not suffer 'as much' as concave anchors in retaining mud. An Excel outperforms a Rocna. The Rocna will not reset until such time it is clean of mud - it will clean the mud off as it bounces across the sea bed - but you might be on a beach before it cleans.
Interestingly Morgans Cloud made their change in recommendation as a result of beachings, I think, in the Med. They did not define the background, no vessel names, no locations. I really don't see much attention having been made to MC's comments - there are still many Rocna on bow rollers - but I have not heard of beachings nor dragging (this thread excepted) of Rocna nor Supreme recently, or since MC made their comments. Historically people were very defensive of their comments on their choice of anchor - we are becoming a bit less loyal
. But being argumentative - people do end up on beaches and it maybe due to a clogged fluke, or debris on the seafloor, or a poor set or.... - when your yacht is on a beach you are not focussed at the why - but how to get the yacht back afloat.My view has always been - Rocna is a good anchor in sand, there are issues in mud - if only the faff of cleaning them. Today there are plenty of options - you do not need to buy a Rocna (which was less true in say 2010 - there was little choice). We now have Ultra, Spade, Vulcan, Viking, Knox, Excel and Epsilon, to name but a few. The Knox was tested and if the slot between the 2 flukes was closed - if clogged. The slot allows the mud to be less adhering. Note that Viking, SARCA, Excel - all have slots or perforations (for a reason).
And - I did test - stainless brings up less mud - but it is a stiff price to pay. If you use your galvanised anchor frequently the working surface of the anchor is polished by the seabed - there is no need to buy a stainless anchor (unless you are into jewellery for your yacht). After much use your stainless anchor will be as rough as a well used galvanised anchor. Stainless is soft and will scratch easily, gal is much harder and will take longer to polish - but the polish will be more robust. Testing less frequently used anchors is a waste of time. Viking are trialling Thermal Diffusion Galvanising - which is harder than normal gal and takes a really nice polish - it looks like black stainless. Check the polish on our chain:
Many stainless anchors do not have Duplex shanks and the shank might not be dissimilar to the strength of a bendy shank anchor. Duplex stainless is very expensive, on top of the cost of 316 and the cost of polishing. Arguably you would be better buying 2 gal anchors, one convex, one concave than using stainless - you need a spare anchor, anyway.
Take care, stay safe
Jonathan
ltcom
Well-Known Member
When i was still sailing my own boat, i bought a 12 V spray washer for peanuts from ebay. Sorted muddy flukes. Sweet memories.
Anchor cleaned and stowed.
KAM
Well-Known Member
The Spade also suffers from picking up debris. When new the top surface was painted yellow. I had thought this was just decoration but maybe it was intended to assist cleaning. I usually leave mine just below the surface and tow it a while to clean.
Stemar
Well-Known Member
One advantage of a cat is that, when the anchor comes up with a load of mud, you can just let it dangle in the water as you move off. No more mud!
My first thought was to wonder about a hard silicone wax like Turtle wax.
My first thought was to wonder about a hard silicone wax like Turtle wax.
NormanS
Well-Known Member
Am I the only one who feels that greasing an anchor so that it slips through the mud, sounds absolutely ludicrous?
sailaboutvic
Well-Known Member
I find super glue works well ,
Neeves
Well-Known Member
There are anchors that do not collect, as much mud, or any mud, just look at the pictures at the end of the article. Kobra, possibly the cheapest in the line up, comes out well.
Gordon Lyall, who led the research team that developed the Delta, used to give lectures in and around Glasgow. His competition was the Bruce anchor. Part of his promotion was that Delta did not collect mud.
'Plus ca change, plus c'est la meme chose'
It has always been bizarre that owners would mention their anchor was received at the bow roller full of mud - and this was accepted as being beneficial and indicative of a good anchor.
Jonathan
Gordon Lyall, who led the research team that developed the Delta, used to give lectures in and around Glasgow. His competition was the Bruce anchor. Part of his promotion was that Delta did not collect mud.
'Plus ca change, plus c'est la meme chose'
It has always been bizarre that owners would mention their anchor was received at the bow roller full of mud - and this was accepted as being beneficial and indicative of a good anchor.
Jonathan
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KAM
Well-Known Member
The Bruce was never a problem with mud but sometimes came up with a large boulder jammed in the flukes. Never considered the Delta an improvement on the Bruce.
doug748
Well-Known Member
They all laughed at Christopher Columbus when he said the world was round
They all laughed when Edison recorded sound
They all laughed at Wilbur and his brother when they said that man could fly
Why, they told Marconi wireless was a phoney - it's the same old cry......
It's the future
..
sailaboutvic
Well-Known Member
They all laughed at Christopher Columbus when he said the world was round
They all laughed when Edison recorded sound
They all laughed at Wilbur and his brother when they said that man could fly
Why, they told Marconi wireless was a phoney – it’s the same old cry...
It's the future
..
Many years ago I met a guy in Greece who was piling petroleum jelly on his hull he said he been doing it for years, keeps fouling off and makes the boat ho faster.
I did laught at the time but who am I to say when I not tried it myself .
Neeves
Well-Known Member
We tried lanolin on the leading edges, bow, keels, rudder - they fouled more quickly than anywhere else.
Jonathan
NormanS
Well-Known Member
Well, maybe, but like my anchor, I'm a "Stick in the Mud"They all laughed at Christopher Columbus when he said the world was round
They all laughed when Edison recorded sound
They all laughed at Wilbur and his brother when they said that man could fly
Why, they told Marconi wireless was a phoney - it's the same old cry......
It's the future
..
mattonthesea
Well-Known Member
IIRC, and that's a big if, didn't SY Panope rid the Supreme of the mud problem by drilling holes in the middle? Presumably that vented the suction of mud on the spade?
Right; who's going to make holes in their hook? ???
Right; who's going to make holes in their hook? ???
pandos
Well-Known Member
I thought about PTFE or sililar just before it was dropped.
I use mine so rarely it is not a problem, but reading anchor threads, and having used my Rocna a few times, (never without it failing to set first time, obviously this is user error?) has caused me to really regret retiring my CQR..
doug748
Well-Known Member
IIRC it did not work too well. Could be wrong, someone will tell us.
Good man.
.
Kelpie
Well-Known Member
Our 25kg Rocna has dragged a handful of times now. We used to think it was infallible- but since going full time liveaboard we must have anchored more in the past couple of months than the rest of our cruising put together.
The common factors have been: slightly iffy holding, generally with some weed; sudden changes in wind speed/direction; not having overly generous scope.
It's always held in 30kts or so, but it's dragged in 40+, even at 6:1 scope. Maybe we've been expecting too much.
A couple of times I've put out what seemed like a silly amount of chain, e.g. 10:1, and that has held fine.
Interestingly, one night we were anchored next to friends who had a bigger boat and a 20kg spade, and they didn't budge an inch, whilst we and several others spent the night dodging 50kt gusts and trying to re-anchor.
The common factors have been: slightly iffy holding, generally with some weed; sudden changes in wind speed/direction; not having overly generous scope.
It's always held in 30kts or so, but it's dragged in 40+, even at 6:1 scope. Maybe we've been expecting too much.
A couple of times I've put out what seemed like a silly amount of chain, e.g. 10:1, and that has held fine.
Interestingly, one night we were anchored next to friends who had a bigger boat and a 20kg spade, and they didn't budge an inch, whilst we and several others spent the night dodging 50kt gusts and trying to re-anchor.
roaringgirl
Well-Known Member
We live aboard and use our 25kg Rocna a lot. I have *never* dragged once the Rocna is set, but if it drags when we back down on it during the setting process, it must be brought to the surface to have the mud scraped off before it is possible to set it again. This suggests to me that if it were to lose grip on a muddy bottom due either to reset or a big wind increase, it might struggle to re-grip because of the mud-ball in it.
I think of the Rocna as a variation on the Bruce "mud bucket", which must be somewhat constrained by the strength of the substrate. Ours is old, well used and getting increasingly rusty; I am looking to replace it with an aluminium Excel, although I can't source one right now. I like the way the Excel digs ever-deeper as it is pulled - this means it will find stronger substrate, whereas a full mud-bucket won't do this.
I think of the Rocna as a variation on the Bruce "mud bucket", which must be somewhat constrained by the strength of the substrate. Ours is old, well used and getting increasingly rusty; I am looking to replace it with an aluminium Excel, although I can't source one right now. I like the way the Excel digs ever-deeper as it is pulled - this means it will find stronger substrate, whereas a full mud-bucket won't do this.
sailaboutvic
Well-Known Member
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 .