New Anchoring Setup for Bavaria 40 Cruiser

[kas_1611]

Tomasz,

Mmm perhaps the Delta is the exception that proves the rule ??

I was meaning for your average sailor looking to improve their security at anchor rather than for serious anchorholics like ourselves. Mind you saying that if I know the wind is going to be getting up into the "survival" zone (that is 55kts plus) I'm saying "bugger anchoring" and heading for harbour!

Keiron

[DoubleWhisky]

Originally Posted by kas_1611

Tomasz,

Mmm perhaps the Delta is the exception that proves the rule ??

I was meaning for your average sailor looking to improve their security at anchor rather than for serious anchorholics like ourselves. Mind you saying that if I know the wind is going to be getting up into the "survival" zone (that is 55kts plus) I'm saying "bugger anchoring" and heading for harbour!

Keiron

We are thinking very similar way. At the moment I have 40 kg Rocna. It is good up to 50 knots of wind (accordingly to the Rocna sizing chart). My intention is to switch to 55 kg one, as I want to have an anchor safely holding in some 60 knots. The difference between 50 and 60 knots of wind make (my boat) for a difference between 1280 kg and 1850 kg of force on the anchor tackle - almost 50 %

By the way - several times I needed to go out of the harbour in the winds of 50 + knots to avoid smashing of the boat by constant keel pondering on the bottom. Some Greek harbours are quite shallow and are not all round protected against the waves...

Back to Delta - I rather suppose it is the problem with Lewmar sizing charts, Delta included. Lewmar is probably one and only real mass manufacturer of anchors and selling mainly to mass boat builders.

The price difference between 55 lb anchor (recommended for my boat by sizing chart) and 110 lb one (equivalent for holding power of 40 kg Rocna) is about $ 1600.
The price difference between 35 lb anchor (recommended for Your boat by sizing chart) and 70 lb one (hardly being an equivalent of 27 kg Knox, but comparable to 25 kg Rocna) is about $ 350.

Lat's assume that mass production builder can save $ 500 on average boat, by equipping it with heavily undersized Delta. This mass producer can still claim, that the boat is equipped in accordance to anchor manufacturer sizing chart. Multiply this saving by 10.000 hulls (less than annual production of each of leading groups) - boat builder has $ 5.000.000 of savings on anchors only, and Lewmar has some $ 5.000.000 turnover - with this building group only...

Lewmar's sizing charts are not strange to me at all

[kas_1611]

Tomasz,

When you put it like that the Delta chart makes perfect sense

Keiron

[kas_1611]

Final got round to getting the tape measure out to check the length from bow roller to windlass and I have a maximum dimension of 800mm.

Looking at the dimensions of the various models and this brings in another complication as the ultimate ideal anchor for some designs simply will not fit at present. As I don't want to have to bugger about changing bow roller or windlass this leaves me scratching my head again.

A 25kg Rocna will fit comfortably as it comes in at 695mm
A 33kg Rocna would be tight at 765mm

A 20.5kg Mantus will just fit at 721mm
A 29.5kg Mantus will not fit as it is 823mm

A 20kg Manson Supreme will fit at 685mm
A 27kg Manson Supreme will fit at 750mm (like the 33kg Rocna it would be tight)

Can't find the internal shank length for the Knox so hard to tell and I haven't looked at the new Rocna Vulcan yet.

This does not allow for a swivel or other chain fitting device so might limit choice again depending on how I fix the chain to the anchor.

Given the numbers I have it boils down to either of the Rocnas or either of the Mansons. The 20.5kg Mantus would do the job for most of the anchoring we do at present but if I'm going to upgrade then might as well go for something that will hold us in a storm. This rules out the 29.5kg Mantus as it won't fit sadly.

So last thing to consider is the working power of the 1000w motor on the windlass and if it will manage 50m of 8mm chain plus upto a 33kg Rocna/27kg Manson. According to the manufacturers manual it has a Max Pull of 1000kg, Max Work Load of 370kg and a normal Work Load of 120kg. Will this cope without damaging the motor and would it deal with an extra 50m of 16mm rode?

Cheers

Keiron

[kas_1611]

Hah! What do you know? Quick search for swivels and I find one for 8mm chain and it is 95mm long. This would rule out the all but the 20kg Manson and the 25kg Rocna (Knox still being unsure of shank length).

Keiron

[noelex 77]

A swivel is not necessary. In fact, if you do fit one you should fit a few links of chain between the swivel and the shank to reduce the side load, so you need a lot of room. You obviously do need to allow distance for a shackle.

Before you go too far I would download the templates. These enable you to print out the anchor shape. Stick this on some cardboard and you can construct a replica anchor which will give you a more accurate idea of what will fit.

The Mantus templates are here:
Mantus Anchors | Anchor Templates

The Rocna templets are here:
http://www.rocna.com/sites/default/f...20-pattern.pdf

Manson have detailed dimensions, but I don't think they offer the option of printing a full sized replica.
http://www.manson-marine.co.nz/Dimen...%20Generic.pdf

[kas_1611]

Noelex, I had seen the templates and thought "that's a good idea" but was considering buying a new anchor this winter for the new season so not possible to trial by template as the boat's in Croatia and we are over wintering in UK.

Given what you say about putting a couple of links of chain between swivel and anchor (something I hasten to add I've not actually seen on other boats with swivels) this would all but rule out all the above choices given the 800mm max distance between roller and windlass. As the 20kg Manson plus swivel comes to 780mm it only leaves 20mm to play with which is not enough for 2 links of 8mm chain.

My reason for thinking of a swivel is we have a lot of fun and games with the Delta coming up upside down onto our roller. No matter how many times I sort out the chain it always does it so I thought the swivel would eliminate this as I'm getting fed up of hanging over the edge trying to manhandle the Delta onto the roller the right way up.

So it might be a new bow roller as well when I come to upgrade unless I can find a shorter swivel or the Knox comes in with a shorter shank length or the Vulcan becomes a possibility. Of course could just drop the swivel which would make life simpler. Could be winter 2015 before I'm in a position to upgrade at this rate.

Cheers

Keiron

[noelex 77]

Understood. The template is no good without the boat to try it on

I have not used a swivel for many years.

The only problem is that if the boat spins around the same way the chain can twist. This is not noticable till you try to raise the anchor when the twists get compressed into the last bit of chain before the anchor breaks out. If there are enough twists the chain bunches up and cannot be retrieved by the winch. Once the anchor breaks out it will spin around and untwist the chain, but without retrieving the chain to close to 1:1 a well set anchor is tough to break out.

This has only happened to me twice so it is a very rare occurrence.

To install a swivel with the short length of chain to reduce side loading needs more room than most boats have. You need a shackle three links of chain and then the swivel.

There is a good article here on swivels here:

Swivel connect

There is a photo of the ideal way to connect the swivel. BTW I believe the author of the article has subsequently ditched the swivel completely.

[chasfgr]

Originally Posted by kas_1611

Noelex, I had seen the templates and thought "that's a good idea" but was considering buying a new anchor this winter for the new season so not possible to trial by template as the boat's in Croatia and we are over wintering in UK.

Given what you say about putting a couple of links of chain between swivel and anchor (something I hasten to add I've not actually seen on other boats with swivels) this would all but rule out all the above choices given the 800mm max distance between roller and windlass. As the 20kg Manson plus swivel comes to 780mm it only leaves 20mm to play with which is not enough for 2 links of 8mm chain.

My reason for thinking of a swivel is we have a lot of fun and games with the Delta coming up upside down onto our roller. No matter how many times I sort out the chain it always does it so I thought the swivel would eliminate this as I'm getting fed up of hanging over the edge trying to manhandle the Delta onto the roller the right way up.

So it might be a new bow roller as well when I come to upgrade unless I can find a shorter swivel or the Knox comes in with a shorter shank length or the Vulcan becomes a possibility. Of course could just drop the swivel which would make life simpler. Could be winter 2015 before I'm in a position to upgrade at this rate.

Cheers

Keiron

My ha'porth - I found no significant difference in the CQR being presented upside down or self-stowing with or without a swivel.
I therefore dispensed with it (and confess I had it direct to shank).
Vyv Cox was going to do some tests with and without a swivel and offer an evaluation - I haven't seen that.

[kas_1611]

Thanks for the input on the swivel. Looks like more trouble than it is worth and as it opens up the larger anchors I'll ditch the idea. I've figured out a good routine for getting the Delta back on the roller the right way up, even if it is a pain in the posterior, so even if a new gen did the same I can right it.

Cheers

Keiron

[kas_1611]

it being a wild and windy day on the Isle of Man I spent some time digging around and finally found the dimensions for the new Rocna Vulcan anchor. Have to say this looks an impressive piece of kit with many of the same performance features of it's cousin without the roll bar. It's also smaller!

Looking at similar weight anchors the Vulcan is significantly shorter along the shank:

A 25kg Rocna comes in at 695mm, a 25kg Vulcan comes in at 530mm
A 33kg Rocna comes in at 765mm, a 33kg Vulcan comes in at 581mm

So this would be an excellent option for those of us with shorter bow rollers or who have genaker poles that would limit the use of roll bar anchors but still give the same setting ability and performance.

I have to admit I could be tempted by a Vulcan :-)

Cheers

Keiron

[peter streit]

I use a 30kg sarca excel and 10mm chain with no swivel on my bavaria 49. Had this anchor for 12 months now cruising Greece and Turkey. I anchor most nights and it gets very windy here. Not once have I dragged. The achor cuts through weed and sets within meters. Very happy

[Stu Jackson]

1. There used to be responses to these "how do you get the anchor to come in right side up" from UK readers who linked to a product that did just that. I do not recall the name of it, nor do I have a link (drats!) (sorry) but it is essentially a piece of metal angled that connects to the anchor and chain end. Perhaps someone remembers.

2. What all of this discussion of anchor and chain is about is what chas called an "anchoring SYSTEM." He's right, it's a sum of its component parts. You size the system by checking the loads against the strength of the parts: anchor holding power, shackles, chain, rode vs. the anticipated LOAD from the boat against the wind. Instead of reinventing the wheel, Nigel Calder explained this all in great detail and has published tables of loads from boat/wind vs the capacities of the components. The earlier discussion of "average boats and average anchors" is absolute rubbish. Where are YOU going to sail and what are the expected wind speeds against YOUR boat?

Here are his tables and some discussion.

Anchor System Sizing Tables (Reply #6) & Why Swivels are a bad idea Ground Tackle & Anchor System Sizing TABLES & Swivels


There is discussion later down that thread from Rocna themselves.

All anchor manufacturers should provide the LOAD their anchors can handle, in addition to the "Idiot Light" tables.

[noelex 77]

Originally Posted by Stu Jackson

All anchor manufacturers should provide the LOAD their anchors can handle, in addition to the "Idiot Light" tables.

This is good idea, but I am not sure anchor manufacturers (or anyone else) know the correct numbers. The results are very dependent on the substrate. The sheer strength of substrates varies from less than 6 Kpa to > 400 Kpa. This, combined with the ability of the anchor to set in different bottom types, produces a lot of variability.

In addition, the forces go up roughly as the square of the windspeed, so a small increase in wind strength from a gust or an inaccurate forecast produce a dramatic increase in the force.

The ABYC forces are not particularly accurate. Some estimate that they overstate the force by 3x, but there is a lot dispute about the allowance that should be made for wave and dynamic loads.

I think our best defence is to use the collective wisdom of forums like this to see what anchor design and size works in practice and choose our anchors accordingly.

Manufacturers are interested in selling anchors and there is great incentive to recommend small anchors. I would not place much emphasis on most of their suggestions, which perhaps is the message behind your post.

One common problem is that sailors intuitively imagine that an anchor that will just hold windspeed X should be able to cope with X+ 50% if they go for an anchor 50% bigger. In fact the anchor needs to be over 2.5 times larger because the force will rise as the square of the windspeed (assuming anchor holding capacity goes up linearly with weight, which is roughly correct).

The philosophy of the "biggest anchor you can reasonable manage" has appeal.

The usual engineering practice of measuring the load and adding a suitable safety factor has some application, but the limitations of the large variability in the parameters combined with a dramatic increase in the theoretical force as windspeed rises means in practice that this approach does not work well.

Some manufacturers at least define the conditions of their anchor size recommendations. These might include a definined windspeed and substrate. Unfortunatly few users would accuratly predict the dramatic increase in anchor size needed to transition from a table that used "25 knots in a good substrate" to an anchor that might be occasionally needed to hold in 35 knots, or more, in a poor substrate.

[J Neeves]

Originally Posted by Stu Jackson

1. There used to be responses to these "how do you get the anchor to come in right side up" from UK readers who linked to a product that did just that. I do not recall the name of it, nor do I have a link (drats!) (sorry) but it is essentially a piece of metal angled that connects to the anchor and chain end. Perhaps someone remembers.

Oscallati market one of these devices (they call it an anchor connector), its in stainless steel and incorporates a swivel. It has no working load limit but I spoke to the Chinese manufacturer and they do intend to rectify this omission. Anchor Right sell a product called the Boomerang made from galvanised high tensile steel. Both self right the anchor. We have been using a device very similar to the current AR product for 6 months now without issue.

From memory both devices are 200/300mm long, need a shackle at each end and the AR product (and that from Oscallati) ideally has 9 links of chain between it and the anchor shank. This does mean you need 3 shackles so you need 'lots' of space.

Jonathan