Anchor size for Bav Ocean 38

[1simon]

Hi All,

My Bavaria Ocean 38 was originally fitted with a20kf CQR.
Its time is up  and needs changing.
I  have read through some reviews and noted the superior holding power and setting capabilities of more modern Rocna and Delta anchors over the traditional CQR's.

My question is - upon choosing one of these modern anchors, should I go  for a 20kg or could choose a 10kg or 15kg, given the superior performance of the modern anchors?

I have noted in some other threads that Rocna and Delta 20kg have been fitted to other Bavaria 38 owners
and wonder if anyone has experience with slightly smaller modern anchors?

Simon

[Craig]

Our Bav 38 ( 2010 model) held in 75kn winds for 3 days with a 20kg Kobra 11 ( similar to Delta) mainly with the one anchor, though we later put down a second anchor closer to the boat.

The CQR anchors consistently rate poorly in anchoring tests. The Kobra and Delta anchors are intermediate in straight line pull tests, but seem to be less prone to weed or rocks jamming in compared with the spade type anchors. The spade type anchors are the best in straight line pull tests.  They also set quite well providing weed and rocks don't jam up the works.. The most I have dragged with wind changes of 180 degrees has been less than 5 metres with my Kobra.

Don't make the mistake and get heavier chain. 8mm chain is quite adequate.

It is almost always better to invest in a bigger anchor than heavier chain.

Best to get the largest size anchor that will fit over the roller.

Craig
"Shirley Valentine"
Gold Coast
Australia

[Ricd]

Agree with Craig on Chain choice (8mm). I have just converted to a 15Kg Rocna on my 34-2000 (6000kg loaded) and it works great,  Never had to re-set it.  I assume the B38 is about 7000kg ish?  That might just be on the cusp of a between a 15kg and a 20Kg.  If you have the money go for the 20Kg.

[Ricd]

Just googled Bav 38 ocean...she is heavier than i assumed...go for a 20kg anchor

[Yngmar]

Rocna's sizing guide recommends a 20kg anchor. Depending on conditions you wish to anchor in, many fit the next size up, as did I (25kg). Neither will fit the bow roller on the 38 Ocean without modifications due to the rollerbar on the anchor. I had to move my bow navigation light and modify the bow roller (thread with photos about that somewhere on here). Alternatively you may wish to consider the Vulcan, Rocna's rollerbar-less alternative that supposedly performs just as well and should fit without these problems - they do have a PDF template which you can print and mount on some cardboard to try it out before ordering the anchor.

[1simon]

Thanks for all the comments.
My chain is 8mm,m and was changed 2 years ago, so  I  believe I will keep the same chain.
And I know the 38 Ocean is a heavy boat for its size.

Will advise when I do change it and if I need further help.

[Lazy Pelican]

We have a 20kg Spade on our B39. We cruise 4 months each season in Greece and anchor most nights. After many seasons we have total confidence in the anchor- provided its properly set!

[JEN-et-ROSS]

We also have a B38, though an older version that's probably even heavier than the Ocean 38, but we still use 8mm chain (80mtrs), and use a
25kg Delta that has never dragged in over 10 years. The bigger Delta also fits the original bow rollers.

[Impavidus]

I have the Manson supreme. On 50 mtrs of 8mm. It is similar to the Rocna, their blurb says;

The Manson Supreme is an anchor that excels on yachts. This next generation New Zealand made anchor conforms to standard bowrollers and has been specifically designed for extreme holding conditions and different seabed types. Use a Manson Surpeme for a good night's sleep onboard and to keep your family safe.

 The Manson Supreme has earned an undisputable reputation worldwide as the highest holding - fastest setting anchor since 2006, when it first hit the market. The bonus design feature in comparison to more classical anchor designs is that the anchor was developed with a dual operation shank to  enable use in rock and coral seabed types.

The anchor has been reviewed by Lloyd's Register EMEA and it received a SHHP status, Super High Holding Power.
 The first and only production boat anchor in the world to do so.


For your size boat they recommend the 35lb which is what I have. 
See here.  http://www.manson-marine.co.nz/StandardSizes/Manson%20Supreme%20Standard%20Sizing.pdf

I have been very impressed with this anchor.

Ant.

[Craig]

Guys,

The weight of the boat is not important in determining anchor size.

It is surface area exposed to the wind that is important. All the Bav 38s, no matter what year or model have roughly the same surface area exposed to the wind. There is a great book, "Harbour Manouvres" written by a couple of Germans that has the figures on wind speed and forces on surfaces for typical boats. It also gives the ratios of above water and below water areas for some Bavaria yachts.

The biggest difference is the extra windage from slab furling sails, as opposed to in mast furling and whether you keep your spray hood and bimini up during a blow.

I'm a part time RYA instructor at Hamilton Island that just got hit by Tropical Cyclone Debbie last week. ( I left just before Debbie hit)  Winds gusting to 150kn for 2 days. The boats that fared best were those that removed all sails, spray hoods and biminis before the blow and were in a marina. Most boat damage was sail damage caused by furling headsails not being removed and lines tied to cleats without proper snubbers. I strongly recommend that lines be taken to winches in extreme conditions.

Strongly recommend that the largest anchor you can fit to your roller is the way to go, no matter what your boat. 

Craig
"Shirley Valentine"
Gold Coast
Australia

[Neil]

I totally agree with Craig's comments about windage.

For a 38 Bavaria I would go for a 25Kg Rocna.

[Ricd]

Interesting comments Craig.  However, I seem to remember, and tend to practice when mooring, that 1Kn or tide is roughly equivalent to 15Kn-20Kn wind.  Sitting at anchor in a 3kn tidal flow (45 to 60 kn of wind equivalent) all pulling directly against the anchor set, the weight of the boat at 3Kn against anchor (eg 600kg versus 10000kg at 3kn) must be pretty important on the size of anchor required to hold it?   Certainly if you end up at anchor in a hurricane the wind will dominate for sure, but probably best not to be at anchor in such conditions.   

[Neil]

The issue of tidal flow for me would be the fact that in many places it will increase and decrease and change direction. A Rocna is great at breaking out and resetting itself in the opposite direction when the flow changes direction. Of course it will do the same for wind changing direction when it is the overriding factor.

When the wind is at higher speeds this tends to result in waves and chop with even a small fetch so I use a nylon snubber as a bridle to the chain. The stretchy nylon quiets everything down nicely and reduces snatch.

[Craig]

1 kn of tide would be equivalent to 20kn of wind if your boat is very heavy and has low windage.

I reverse on my anchor at 2000rpms to ensure it digs in. This is equivalent to 5.4kn of tide as I go at 5.4 kn under motor in windless conditions at 2000rpms. It is also equivalent to about 40kn of wind as I can easily, but slowly, motor against this wind at 2000rpms in flat seas. I have the Volvo D1-30 engine in my Bav 38.

Wind and/or tide changing direction would pull out almost any anchor. Not much force is required in the opposite direction to pull out an anchor compared with its load when properly set. That is why I always consider the resetting ability as being just as important ( if not more so) in deciding on an anchor. This is the reason why the CQR ( Plough) anchors can be dangerous.

A short nylon snubber will settle down the noises from the roller but has little effect on the "snatch". The "snatch" loadings are not large when compared with the static loads. The largest loads occur when a yacht yaws ( goes from side to side) on its anchor. The loads when it suddenly changes directions are about double the normal load, not an exponential increase similar to what you get by having a load suddenly put on a line. I suggest that the yawing can be almost eliminated by placing a second anchor much closer to the boat than the main anchor.

I go into Marinas if the predicted wind speed is 30kn or more, however, I have been caught out a number of times in thunderstorms where winds in excess of 60kns occur for short periods of times. ( up to 1/2 hour).

I strongly suggest that anchoring in changing tide conditions is dangerous and should be avoided. You only need a bit of weed, or rock to jam in your anchor for it to become ineffective when resetting. This can happen to almost any type of anchor but suggest it is more likely to occur if your anchor has a roll bar.  Mooring buoys are great for changing tide conditions.

Craig
"Shirley  Valentine"
Gold Coast
Australia

[Neil]

Craig,

Agree about the CQR style, a complete waste of time, and my old one is in my garage with lots of other useless junk.

As for anchoring in changing tide/wind I do this often and have no issue. My Rocna sets in its own length easily and reliably in sand and mud. I would normally also set an anchor alarm and sleep easy. In kelp or rocky bottoms I would be more circumspect.

As for yawing I do a lot of that due to the relatively high freeboard. The bridled snubber helps a bit but I should really carry a second anchor and/or set a bit of cloth at the stern, but haven't bothered.

[KiwiBeanie]

We recently changed from the original cqr to a 20kg rocna on our b40. The  rocna sets quickly and holds fast. Much better than the cqr which would sometimes take a couple of goes to set. It hasn't dragged on us yet. The worst winds so far have been 25 knts with the swell running perpendicular so we swung around a bit. We had a sleepless night because of the swell but the anchor held.