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Old 02-06-2021, 16:08   #1
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Dragging my Rocna - Is my technique at fault?

So I replaced the toy delta on my Hunter 38' with a 25kg Rocna original on 200' 5/16" G43. Should be sized correctly for my boat.

I've anchored out four or five nights and drug two of the five. Admittedly the dragging was in soft mud, but possibly my technique is also at fault.

FWIW I drug in the river by R42 (R44?) Veterans Memorial Bridge, Daytona, and at Sheepshead Cut just south of Fernandina. Both times in 15kts with 5:1 scope out. Sheepshead Cut I would never have anchored, very large fetch, wind opposing current, > 6' tidal range, right in the mouth of a creek, soft mud....ugly but was with another boat. I bailed after two attempts and picked up a mooring at Fernandina.

Successful anchoring in Lake Syliva, and by Merritt Island Causeway.

Onto my technique:
1. Bring boat to a stop at chosen point, aligned with other vessels at anchor nearby if any, otherwise into wind
2. Lower anchor until its resting on the bottom
3. If the wind/current is pushing the boat down wind/current then pay out the anchor chain to keep it just vertical until 2:1 (this from Rocna pamplet), otherwise engage in reverse idle to do the same thing
4. Snub the chain, look for the chain to be "bar straight" and not doing a "snatch and relax" or any vibration in the chain indicating skipping
5. Continuing the motion in step 3, go to 5:1
6. Back down on the anchor starting around 1,000 rpm, increasing to 1,600-1,800 rpm for a minute while checking bearings to nearby land-based points

Am I doing something wrong, or just unlucky with bottoms?
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Old 02-06-2021, 16:14   #2
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Re: Dragging my Rocna - Is my technique at fault?

I just started anchoring with a new 45lb mantus. A few threads on CF say that with new generation anchors you only need 4:1 scope. My cruising friends say you need more scope than 5:1 even with new generation anchors. I have dragged once because I was close to 4:1. I think you are doing things right just increase your scope and see how things go. Stay with 7:1 and see how things go.
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Old 02-06-2021, 16:35   #3
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Re: Dragging my Rocna - Is my technique at fault?

We anchored 2,000 nights in 30 countries with our rocna and pulled once!

In soft mud you need more scope and patience to allow the anchor to sink deep into the mud before setting. 5 to 1 scope before setting and then let out more. In deep mud at the Pacific end if the Panama Canal we waited 30 minutes before attempting a set.
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Old 02-06-2021, 16:42   #4
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Re: Dragging my Rocna - Is my technique at fault?

You basically have a hurricane anchor for that size boat.


Are you using the depth off the chart to calculate your (skimpy) 5:1 scope?

Did you account for the 6’ additional depth at high tide? Anchoring in shallow Florida places, then adding 6ft of extra depth from the tide can really reduce your scope.

Did you drag near high tide?

I use 10:1 personally and have never dragged in my life. I know a lot of people like to use 5:1 or whatever. 7:1 is my dead minimum. If I can’t get 7:1 or more out, I’m not anchoring there.

I also agree with moondancer. The more scope you have out when you set the anchor, the better and deeper the bite will be. I mean picture it. At 2:1, you’re kind of setting it with the tip pointing a bit toward the surface of the water. At 7:1, you’re setting it with the tip parallel to the sea bed. It’ll just dig in better.
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Old 02-06-2021, 16:52   #5
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Re: Dragging my Rocna - Is my technique at fault?

How deep was the water in those spots where you dragged? In real shallow depths I've found that a higher numerical scope is required, but in 25+ feet or so, 5:1 should be more than adequate.

And in those shallow spots, do remember to include the tidal height swing and the height of your bow roller into the calculations, for those numbers become more of a factor than in deeper water.

But the bottom line is that in soupy mud Rocnas and other scoop type anchors are less effective due to their relatively low fluke area and shallow attack angles.

Good luck in the future...

Jim
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Old 02-06-2021, 17:01   #6
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Re: Dragging my Rocna - Is my technique at fault?

Try not to pull on the anchor at all until the full scope is out. It won't set well at very short scope and you risk packing it with mud if it drags too far. In addition, let the boat come back gently to take up tension on the ride, then give it a harder pull as it comes tighter. Don't go flying backwards and expect to come to a screeching halt.
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Old 02-06-2021, 17:26   #7
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Re: Dragging my Rocna - Is my technique at fault?

Always oversize your anchor. Go one up whatever the manufacturer’s chart says as long as you can allow the space. We are 58 feet, 40 tons. Rocna54. We never back down. With a heavy boat, the wind drift is more than enough. When launching, we find the a Rocna will fly forward like a fishing lure if we free wheel the clutch. This means no chain falls on the anchor. We have the chain marked in 20 foot shots. Knowing the depth, we pick the spot and dump 5:1 or more. In most of the Caribbean, sand so great holding. Never drag there, ever. We dragged in Newport during Hermine with 180 feet out in ten feet. Every wild swing pulled a half meter. The solution was to steer using the wind driven current to reduce swing.

I think you will be OK with more scope. The chain in your locker does you no good.
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Old 02-06-2021, 17:36   #8
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Re: Dragging my Rocna - Is my technique at fault?

There's some good advice above.

Setting in mud can be difficult with roll bar anchors like the Rocna as the mud can pack up against the roll bar keeping it from setting fully. Don't set at 2:1 - let out the 5:1 (including the height of the anchor roller and high tide) as the boat drifts back. Then give the anchor successive short pulls with the reverse letting the chain relax in between. Start with quite a low RPM to just lift the chain from the water. In later pulls go slowly to higher RPMs. This will let the anchor work down into the mud.

Also inspect your Rocna to make sure the shank is perfectly straight. Even a small bend to the side can make it not set reliably. Also make sure that the fluke is smooth. SV Panope's anchor tests found that an older Rocna performed terribly. He's just gotten a newer one that seems to have improvements. Presumably, you new anchor is similar. It will be interesting to see if it tests better.

The Rocna part starts at 12:00
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Old 02-06-2021, 17:38   #9
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Re: Dragging my Rocna - Is my technique at fault?

Quote:
Originally Posted by rslifkin View Post
Try not to pull on the anchor at all until the full scope is out. It won't set well at very short scope and you risk packing it with mud if it drags too far. In addition, let the boat come back gently to take up tension on the ride, then give it a harder pull as it comes tighter. Don't go flying backwards and expect to come to a screeching halt.

Very good advice. I still haul by hand, so I have a real "feel" for the anchor rode. At about 2:1 I'll take a small "feel" to see if I "get a bite" but always let more out immediately. Don't expect it to hold you right away, although there is great merit to the claims of "Holy Cow it pulled me right off the bow!" when folks start using new gen anchors.


Good luck, good question.


PS - I've had my Rocna since 2007.
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Old 02-06-2021, 17:40   #10
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Re: Dragging my Rocna - Is my technique at fault?

It was written that a 25 lb. Rocna is a hurricane anchor for that boat, but I disagree. It may be that Nicholson58 feels similarly: he wrote "always size your anchor one up from the recommendation," which I thought was a subtle suggestion.

Take a look in the 40+ lb. range.

And, what Jim said about the depths... I'm sure there's all kinds of maths to explain why it is, but experientially, it takes huge scope relative to depth to anchor safely in shallow water (say, anything under 20 ft.). It just does. It is something to accept. So, the guys who are telling you to put out still more scope have a point. But, the problem is that with crowded anchorages, sometimes taking enough scope and swing circle space becomes antisocial. I think you'll do better with a heavier anchor, AND adequate scope.

Ann
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Old 02-06-2021, 17:42   #11
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Re: Dragging my Rocna - Is my technique at fault?

Quote:
Originally Posted by Chotu View Post
You basically have a hurricane anchor for that size boat.


Are you using the depth off the chart to calculate your (skimpy) 5:1 scope?

Did you account for the 6í additional depth at high tide? Anchoring in shallow Florida places, then adding 6ft of extra depth from the tide can really reduce your scope.

Did you drag near high tide?

I use 10:1 personally and have never dragged in my life. I know a lot of people like to use 5:1 or whatever. 7:1 is my dead minimum. If I canít get 7:1 or more out, Iím not anchoring there.

I also agree with moondancer. The more scope you have out when you set the anchor, the better and deeper the bite will be. I mean picture it. At 2:1, youíre kind of setting it with the tip pointing a bit toward the surface of the water. At 7:1, youíre setting it with the tip parallel to the sea bed. Itíll just dig in better.
I calculate scope by taking current (or projected at high tide) depth under the keel, which I read directly off the depth meter, then add 10' for the keel and the distance from surface to bow roller.

I was dragging in Sheepshead Cut immediately. Reset it twice then decided it was a lousy anchorage and picked up a mooring ball.

In Daytona I dragged 20' in the time it took to eat dinner, maybe 1:30. Tide was not a significant factor.
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Old 02-06-2021, 17:43   #12
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Re: Dragging my Rocna - Is my technique at fault?

Quote:
Originally Posted by s/v Moondancer View Post
In soft mud you need more scope and patience to allow the anchor to sink deep into the mud before setting.
I'm curious about this. Patience is not my forte lol

What exactly do you mean? How does "patience" translate into technique?
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Old 02-06-2021, 17:44   #13
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Re: Dragging my Rocna - Is my technique at fault?

Quote:
Originally Posted by Jim Cate View Post
How deep was the water in those spots where you dragged? In real shallow depths I've found that a higher numerical scope is required, but in 25+ feet or so, 5:1 should be more than adequate.

And in those shallow spots, do remember to include the tidal height swing and the height of your bow roller into the calculations, for those numbers become more of a factor than in deeper water.

But the bottom line is that in soupy mud Rocnas and other scoop type anchors are less effective due to their relatively low fluke area and shallow attack angles.

Good luck in the future...

Jim
Daytona was something like 5-7' under the keel so 10'-12' total depth. Sheepshead Cut only 2'-3' under the keel, maybe less. Was dead low tide.
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Old 02-06-2021, 17:46   #14
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Re: Dragging my Rocna - Is my technique at fault?

Ann,

The OP said the anchor is 25 kilograms. So that’s pretty beefy for his boat. Agree 25 lbs would not be.
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Old 02-06-2021, 17:48   #15
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Re: Dragging my Rocna - Is my technique at fault?

Quote:
Originally Posted by JPA Cate View Post
It was written that a 25 lb. Rocna is a hurricane anchor for that boat, but I disagree. It may be that Nicholson58 feels similarly: he wrote "always size your anchor one up from the recommendation," which I thought was a subtle suggestion.

Take a look in the 40+ lb. range.

And, what Jim said about the depths... I'm sure there's all kinds of maths to explain why it is, but experientially, it takes huge scope relative to depth to anchor safely in shallow water (say, anything under 20 ft.). It just does. It is something to accept. So, the guys who are telling you to put out still more scope have a point. But, the problem is that with crowded anchorages, sometimes taking enough scope and swing circle space becomes antisocial. I think you'll do better with a heavier anchor, AND adequate scope.

Ann
I think you misread

25kg (or maybe its 20kg) so 45lb.

I do need to find a way to tell the people that anchor too close to bugger orf though. I tried the "bitch wings" on the guy at Merritt Island and got a shrug. Maybe I should sail nekkid.

FWIW the first time I used the anchor, in Lake Syliva blowing 20kts and gusty, I used the above technique and at 2:1 scope the boat stopped hard...almost knocking me over. Perhaps I have an expectation it will always be like that.

Another question, perhaps, is "some" drag acceptable? If so, how much?
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