Upsizing anchor - suggestions?

[thinwater]

Originally Posted by Mike Banks

You could use an old shoe as an anchor if you put out enough chain--but I think your anchor is too light and you do not have enough chain. Manson Supreme is my pick. NEVER had any problems, but not cheap, and I always use an oversized anchor and plenty of chain AND a kellet. I ALWAYS use a kellet in any stormy conditions. ESPECIALLY with an all chain rode--it will stop your bow cleat ripping out of your deck.
.

Oh dear. Where to start....

[Panope]

Originally Posted by Dockhead

Thanks again for all this great work, Steve. You've done a huge service to the cruising community.


Another anchor quality which in my subjective experience does not scale 1:1 is setting behavior. And I think setting behavior is far more important than ultimate holding power, since it is not that hard to choose an anchor which, when well set, has more than enough ultimate holding power even in weak seabeds. Not being able to get the anchor well set is in my experience a far more common problem than lack of ultimate holding power.


My experience, and others have written about similar experiences, is that setting behavior improves disproportionatley with size, and seems to take some kind of leap when the anchor is over 100 pounds. I think Dashew and someone else have written about this, and I think I've experienced it myself. Have you done any work on this?

I would like nothing more than to conduct meaningful INITIAL SETTING tests but I have not been able to find a seabed (other than cobblestone) that challenges ANY common, genuine (not copy) anchor.

I have spent significant effort exploring my area with CQR, Bruce, Delta (anchors with notorious week setting behavior) and they all set right away. I have tried using horrible technique (no chain, short scope, dump and yank) hoping to amplify a setting weakness with no luck - they all just set.

It appears that a weed covered seabed is my only option (besides the cobblestone). So far, I have only conducted a brief "engineered" test where I carefully placed anchor toes directly on stacks of leafy weed. The results were predicable: The heavier anchors/toes penetrated easily, light anchors were defeated.

We do have areas with significant eelgrass coverage but I have purposely avoided testing in eelgrass to avoid becoming the local Salmon habitat destruction pariah.

In the past I stated a my desire to travel cross continent (Florida?) with the test the test boat and a hoard of anchors in order to find a challenging seabed (coral sand?). Unfortunately, my efforts at fundraising have failed to yield the needed amount of money to cover such a venture.

Someone else (in some far away land) will need to pick up this torch.

Steve

[ranger58sb]

Originally Posted by soopad00pa

To chime back in on setting my 10kg roc with 20ft of chain, I've never in the 10ish times I've set the anchor had an issue with it setting quickly and securely.

I drop the anchor and play out a 5 to 7 scope (7 if I have the space and if it feels to tight to get 5,I move on) and wait a couple of min doing other boat stuff. Then I back down slowly increasing rpms as I sight markers. Never any slippage.

Of the half dozen overnights, there've been no problems except for the one prompting this post. I was beginning to wonder what all the fuss was about...

My impromptu analysis: not enough info.

Wind and current -- force and direction(s) -- versus substrate make-up at each location? Force applied by engine horsepower during setting? How far was the anchor below the surface? Et cetera.

Conclusion: you may or may not have been set securely for a surprise storm at any or all of those locations.

IOW, coulda been 9 good "storm-worthy" sets... or not.

Not at all meaning to beat you up about it. It's just that I've discovered (yep, not the easy way) that "set" sometimes doesn't mean "SET."

(In our case, it's also not so easy to know when enough engine power is on the verge of becoming too much engine power for any anchor in any conditions, given that we were starting with 900-hp and now have 1800-hp. Still working on that...)

-Chris

[flightlead404]

Originally Posted by Dockhead

No. Put the weight into the anchor, not the chain.

But don't upsize either to the point that you can't manage the ground tackle. Do you have a windlass?

If no windlass, than 15kg starts to get pretty -- athletic -- to handle. It will work a lot better than 10kg, but 10kg should be enough for a Catalina 30.

Chain is very good, but likewise, it is hard to handle a lot of chain without a windlass.

I would suggest a couple of possible approaches to this:

1. Add a windlass (if you don't already have one), then go up to 15kg and more chain (not necessarily 100 ft.), with octoplait spliced on to the end of the chain.

2. Don't add a windlass, but go up to 15kg if you are comfortable handling that. Add more chain, but not more than you can handle, and prioritize the anchor.

3. If not, then consider a better rather than heavier anchor. Rocna is a pretty good anchor (I had a 121 pound Rocna for a few years), but Spade will set much better and hold more reliably, especially in the smaller sizes. Costly but worth it.




Whichever way you go with the gear, be sure your technique is also up to snuff:

1. Be sure and SET the anchor. It will fairly often not set itself. Back down on it gently and for a long time, gradually increasing the force. If the anchor doesn't eventually hold a full power pull in reverse, it's not set. DIVE on the anchor and check the set, when you can. Do not be in such a hurry for your sundowner that you fail to spend enough time on this process. Properly setting the anchor often takes half an hour or more.

2. Be careful about the choice of bottom, and be careful about a sloping bottom. If you can't find a flat spot to put the anchor into, then anchor in the deepest spot in a cove, so that the slope is UP in every direction from where your anchor is. It's worth going to somewhat shorter scope if necessary to get this. Also the bottom itself is usually better at low points, as silt flows downhill.

3. Use appropriate scope. Count the height of the bow roller in your calculation. With a small Rocna you would normally want at least 5:1 except in deep water, and 6:1 is desirable (but much more than that is diminishing returns). In deep water with a very large (186 pounds) Spade, we go as little as 2.5:1, but that is a special case.

Good luck and let us know how you get on.

I will add to this with my noob experience over the last year with a 25kg Rocna and 200' 5/16" G43.

I dragged several times in my first month or two, then altered my technique and have not drug since.

First, you have to define "drag". If you are measuring from the exact place and instant your anchor hits the bottom, you will always have some "drag". It takes some time, and movement across the bottom, for the anchor to bite and hold, and if you have a bunch of chain you also need to straighten out the chain. Depending on the bottom, scope etc this can all add up to 10's of feet. I started out making the mistake of calling this "drag" but its not really "drag". I would define drag as movement across the bottom after the anchor is confirmed set.

Second, as the above mentions, patience is important. The softer the bottom the more patient you have to be. In super soft "pluff" mud (e.g. the Daytona beach anchorage by R44) it will take quite a while for your anchor and chain to sink into this bottom before it will hold. Like at least 30-45 minutes, maybe longer. I have found that doing any sort of power set in this bottom before then will just slowly pull your anchor along the bottom. In fact, I don't power set at all in that stuff (prefer to avoid it altogether in fact, its nasty pulling that crud back aboard). In that stuff I put out extra scope and don't power set at all, I just mark my drop on the GPS, take some cross check bearings, and watch it for at least an hour.

Finally, somewhere (Rocna material maybe?) I saw a recommendation for an initial "snub" at around 2:1. Don't do it. I will carefully veer out chain to keep the fall off the bow roller off the vertical, veering more out as the boat drifts down off the anchor, to keep the chain as straight as possible, then snub it at 5:1.

HTH

[seandepagnier]

Originally Posted by Panope

I have examined two different sizes of Rocna (rollbar) anchors and found no differences in design. They were scaled versions of each other with the exception of plate thicknesses being scaled slightly differently due to (presumably) material being readily available in a limited number of thicknesses.

You said they are scaled versions of each other with the exception of plate thickness scaled differently. So you agree they are not exactly scaled versions of each other.

https://www.defender.com/pdf/rocna-sizing-chart.pdf

the 10kg has 123 sq in
the 15kg has 160 sq in
the 20kg has 177 sq in

The 15kg increase surface by 30% over the 10kg
the 20kg increase surface by 10% over the 15kg

[rslifkin]

Originally Posted by seandepagnier

the 10kg has 123 sq in
the 15kg has 160 sq in
the 20kg has 177 sq in

The 15kg increase surface by 30% over the 10kg
the 20kg increase surface by 10% over the 15kg

That's not as far off as you think. The 15kg is 50% heavier than the 10kg. But the 20kg is only 33% heavier than the 15kg.

[seandepagnier]

Originally Posted by rslifkin

That's not as far off as you think. The 15kg is 50% heavier than the 10kg. But the 20kg is only 33% heavier than the 15kg.

I realize this.. but the point is, the anchors are not sized linearly. If it were, the 15kg would have 161 sq in (very close) and the 20kg would have 195 sq in (not very close to 177 sq in)

[Breaking Waves]

Originally Posted by Panope

I have not been able to find a seabed (other than cobblestone) that challenges ANY common, genuine (not copy) anchor.

Interesting.

I am curious if in part this is because you have #1 a video camera watching the anchor and so can/could see if it has set or not. Most cruisers anchoring have no idea at all what is going on with their anchor. and #2 You have now set a whole wide range of anchors thousands of times, so have a shed-load of experience and knowledge.

I know bottom composition would be part of this, but I also know a not insignificant number of cruisers have trouble getting a set on even pretty decent bottoms. So it seems like there might be something valuable to learn from your ability to set pretty much any anchor easily in your range of bottoms (except the cobbles).

There may be more skills/knowledge/experience curve to this and less 'hardware effect' than is generally understood. You know what a well-set anchor feels like, because you have done it with multiple designs over multiple bottom conditions while watching video - by observation, many cruisers simply don't know what it should feel like, even ones who have been out cruising for a while.

[Doughdish]

I concur with the comments on Steve Goodwin's work on anchor testing. Arguably the most informative anchor testing data available which provides great insight into how different anchor designs perform relative to each other. In my view, Steve's resetting data is of particular value when deciding on a suitable anchor especially when thinking about the Bahamas. Thanks Steve!

[rgleason]

I dont believe that is true, strictly speaking. The catenary of the chain reduces max load on the anchor and helps reduce anchor angle to seabed somewhat, but at higher wind speeds it becomes less effective (40knts) as it is straightened out.

Then it is very important to have a snubber or elastic nylon rope with adequate scope to cope with wind gusts, wave surges, and boat veering to reduce max loads on the anchor.

I would say a modern bigger ancher with more area would be the answer with adequate rope scope

[Panope]

Originally Posted by Breaking Waves

Interesting.

I am curious if in part this is because you have #1 a video camera watching the anchor and so can/could see if it has set or not. Most cruisers anchoring have no idea at all what is going on with their anchor. and #2 You have now set a whole wide range of anchors thousands of times, so have a shed-load of experience and knowledge.

I know bottom composition would be part of this, but I also know a not insignificant number of cruisers have trouble getting a set on even pretty decent bottoms. So it seems like there might be something valuable to learn from your ability to set pretty much any anchor easily in your range of bottoms (except the cobbles).

There may be more skills/knowledge/experience curve to this and less 'hardware effect' than is generally understood. You know what a well-set anchor feels like, because you have done it with multiple designs over multiple bottom conditions while watching video - by observation, many cruisers simply don't know what it should feel like, even ones who have been out cruising for a while.

It just has to be all about the seabeds.

My setting technique is (purposely) atrocious: Chain dumped on the anchors, No chain, Short scope, 2+ knot back down speeds, No "soak" time, etc. No problems. ALL genuine anchors (except Fisherman) set perfectly (initially)(assuming no foreign debris).

And then there is the 180 degree reset tests at 3.5 knots. Anchors are ripped out of the seabed and must re-engage at high speed. I have performed this (arguably ridiculous) test many dozens of times with CQR anchors and they just re-set EVERY SINGLE TIME.

This is in contrast to countless photos that NOELEX shared from the Mediterranean. We saw crystal clear images of CQR, Delta, and many other anchors at the end of very long furrows with only a small part of the anchor engaged.

My journey to the Pacific Coast ("Surf Sand" tests) by truck was initiated SOLELY to find a seabed that might challenge the CQR and other convex anchors with low tip weights. Again, it was a bust as all good condition, genuine anchors set immediately (sand was hard enough on which to operate a 2 wheel drive vehicle).

Port Townsend is arguably the "saltiest" place in Washington State. 1/3 of the sailboats use CQR anchors and their owners generally love them.

Steve (desperately seeking challenging to penetrate seabeds)

[Breaking Waves]

Originally Posted by Panope

It just has to be all about the seabeds.

OK, interesting.

It may not be much help, but closer to you than Florida, I'm pretty sure you can find some more challenging bottoms both on the Calif coast and in Baja. I know in those areas quite a few of the times I dove on our bruce and Ray only one fluke would be dug in and often not all that far. But that would still be a massive road trip.

[Pete7]

Originally Posted by soopad00pa

Right on. I do think it's likely I fouled or bounced across something unsticky, but who knows. Would've liked more scope, but there were other considerations that made me feel there was only so much rode I could let out. But that's also a function of inexperience - eyeballing a site and figuring out how much room you've got.

We swopped out a 10Kg Rocna roll bar for the 12Kg Vulcan. Only used the new Vulcan a few times so far, but no issues. We have 45m of 8mm chain btw.

So we gained 20% in weight. However, there were a couple of other deciding factors. We keep the anchor in the anchor locker and the 12Kg Vulcan is about as big as I can go. Also Amazon UK was running a pre-order special at nearly 50% off the local chandlers prices last year and that was too tempting.

In use with either anchor I can lift it when its calm or there is no tide running. If the wind picks up, I use the windlass or ask the wifey to motor up to the anchor.

Pete

[Anders]

Originally Posted by Pete7

We swopped out a 10Kg Rocna roll bar for the 12Kg Vulcan. Only used the new Vulcan a few times so far, but no issues. We have 45m of 8mm chain btw.

So we gained 20% in weight. However, there were a couple of other deciding factors. We keep the anchor in the anchor locker and the 12Kg Vulcan is about as big as I can go. Also Amazon UK was running a pre-order special at nearly 50% off the local chandlers prices last year and that was too tempting.

In use with either anchor I can lift it when its calm or there is no tide running. If the wind picks up, I use the windlass or ask the wifey to motor up to the anchor.

Pete

Why are you changing from the Rocna to the Vulcan? Has the Rocna not lived up to your expectations?

[Lodesman]

Originally Posted by noelex 77

I think you are misunderstanding the results.

Sorry I wasn't clear. I couldn't find anything that corresponded with your assertion that his studies showed a proportional relationship between weight and holding ability.

What I found seemed to be that his research suggests performance gets progressively better as anchor size goes up. Until you actually look at his results.

The Spade results posted are based on "guesstimated" data. If you take the actual data as shown on the charts, there's no difference in efficiency between the two Spades, so tend to support the "proportional to weight" theory. However, looking at that data for the Delta, the larger anchor is less "efficient" than the smaller, so maybe holding ability is not proportional to weight.

Knox certainly had some clever ideas, but I have reservations about a lot of his research.