Dragging my Rocna - Is my technique at fault?

[BlackHeron]

I like to let the anchor snap a tiny bit at about 2x scope to be sure the rollbar has turned the anchor over and that the chain has not fouled and wrapped around the anchor. I can feel the chain waggle as the chain tightens up a bit as the anchor aligns itself correctly. I hit the button to pay out more rode instantly before the anchor has a chance to skitter across the seafloor, or stop the boat. What I'm doing here is mainly letting the chain get a bit stiff and allowing everything to align correctly. The last thing you want to do is dump.a pile of chain on the anchor itself.

It depends on how fast the wind/current/reverse-gear is moving the boat away from the drop zone but I like to feel the chain give me some feedback that I am not just dropping a pile of chain on the floor again.

If we are moving too fast I might let the chain slow us down a tad, but not with enough force to jerk the hook out or totally stop the boat backing until we are closer to at least 6:1 but 7:1 is better. If there is room for 10;1 we'll go right nto that and then hook the Mantus hook and snubber bridle on at that spot on rhe chain. The bridle length is just about 9:1 to the water so i don't really need to factor in freeboard. The hook should be right at the water when we are tight and backing down.

We will back down hard in reverse at 1/2-3/4 throttle only after we set the bridle up and the rode is just firm tight. If the hook and bridle drops as we are backing down then I know it hasn't set correctly and jumped, or it dove down and back. I rest a hand on one of the bridle lines as it comes up through the bow-chock and can feel any skittering or movement. Any jerkiness is very easy to feel on the stretchy nylon snubber bridle like a stand-up bass string vibrating under your finger. A little experience will tell you right away if it is a good set or if the anchor is moving by a vibration or lack of one.

The helm is watching the GPS as they back down and between the person at the bow and the helm it is obvious when the job has been done correctly and the two points of data back each other up. If both of us give a thumbs up from our different stations we know we are done.

The Mantus M1 sets almost every time, first time -unless it isn't allowed to fip over at shorter scope or there is crap on the bottom to foul it. We've found crap like thick brush/sticks, a crab pot, and even a heavy down parka fouling the plow when the intial set didn't feel right.

[macman4190]

From the Rocna manual
Deploying rode and setting the anchor
Drop the anchor with the boat stationary or starting to drift back with the wind or tide. Try to let the rode out consistently as the vessel drifts back, but avoid snubbing until at least three times the water depth or more has been paid out. Although the Rocna and Vulcan are designed not to snag the rode, avoid piling the chain on top of the anchor.
A 3:1 ratio of rode-length to depth is minimum (1 being the vertical distance from the seabed to the bow roller). Generally speaking about 5:1 is appropriate. If swinging room is tight, the anchor may be set at 5:1 or greater before recovering some rode to finally swing at 3:1. In any wind you can just let the bow wipe off to provide the force to set the anchor; in calm conditions motor backward slowly.

[Mike OReilly]

I had no idea anchors came with manuals . I sure don't recall getting one with my Rocna, but maybe I ignored it -- I'm a guy after all .

BTW, I basically agree with its recommendation and approach.

[carstenb]

Originally Posted by Mike OReilly

. I sure don't recall getting one with my Rocna, but maybe I ignored it -- I'm a guy after all .

Real men don't read the instructions until afterwards

[kapnkarl]

Great thread!! Thank you all!!!

[Chawes]

It comes down to how much room you have to swing. If you have no neighbours great let out as much as you have. 150 , 200 feet. But if you have neighbours ask how much they have out . Most captains like at least 150 feet. We drop our anchor and play out the chain until it comes tight. Then we wait motor running. Have a beer. We then reverse on the Anchor and see it’s holding. We put out another 20 feet put on the snubber another 10 feet.
Make a waypoint and watch. Then turn off the engine and have a cocktail! Side note anyone who said they have never dragged either does not anchor often or is flat out lying! Haha.
Keep trying until you get it right , more is better.
Cheers from the Caribbean!

[Dockhead]

Originally Posted by flightlead404

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 d
o 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?

That's more or less OK process.


Just a couple of things:


1. Don't back down on it at 2:1. Some anchors do ok like that, but not the Rocna. You need at least 3:1, 4:1 before you do that. Count the height of the bow roller in your scope calcuation.



2. In soft mud, let it soak. Take your time. Rocna is not at all the best anchor in soft mud, because the roll bar clogs. So give it time.


3. Finish your backing down with 5 minutes or more of full power. If the anchor is really set, you won't drag. You won't know if it's really set, if you don't apply full power.

[flightlead404]

I have a Fortress FX-11 on 50' 5/16" G43+150' 9/16" 8-plait spliced to a thimble with a 3/8" Crosby 209A (?) shackle to join the two parts of the rode and the anchor to the chain.

I could use that in soft mud but I can't deploy it easily until I finish my bow roller repair (this weekend hopefully).

I also use a snubber I made up from 25' of dock line bent to a chain grabber (the Suncor style whatever that's called) with an anchor hitch and an eye spliced in the other end so I can use a larks foot thought the anchor clear. I then take a loop of the loose chain around the cleat also, just in case the snubber fails for some reason I won't be pulling on the windlass.

[Lodesman]

Originally Posted by Mike OReilly

I had no idea anchors came with manuals . I sure don't recall getting one with my Rocna, but maybe I ignored it -- I'm a guy after all .

BTW, I basically agree with its recommendation and approach.

I definitely did not get a manual with my Rocna, but see they're available online (in many languages): https://rocna.com/users-guide/
I'm guessing it was written in 2014.

[malbert73]

Originally Posted by Dockhead

That's more or less OK process.


Just a couple of things:


1. Don't back down on it at 2:1. Some anchors do ok like that, but not the Rocna. You need at least 3:1, 4:1 before you do that. Count the height of the bow roller in your scope calcuation.



2. In soft mud, let it soak. Take your time. Rocna is not at all the best anchor in soft mud, because the roll bar clogs. So give it time.


3. Finish your backing down with 5 minutes or more of full power. If the anchor is really set, you won't drag. You won't know if it's really set, if you don't apply full power.

I totally get it about full reverse but I don’t think it generates that much force for me.
I prefer to set the anchor then allow chain to settle and spring boat forward. Then I back aggressively 2-3 times against the catenary until the boat jerks to a stop. I feel I get much more force with jerking back against the chain than static reverse. Plus it’s kind of fun that the Mantus may as well be anchored in concrete for how quickly it stops the boat, especially compared to the CQR I grew up with

[Dockhead]

Originally Posted by flightlead404

I have a Fortress FX-11 on 50' 5/16" G43+150' 9/16" 8-plait spliced to a thimble with a 3/8" Crosby 209A (?) shackle to join the two parts of the rode and the anchor to the chain.

I could use that in soft mud but I can't deploy it easily until I finish my bow roller repair (this weekend hopefully).

I also use a snubber I made up from 25' of dock line bent to a chain grabber (the Suncor style whatever that's called) with an anchor hitch and an eye spliced in the other end so I can use a larks foot thought the anchor clear. I then take a loop of the loose chain around the cleat also, just in case the snubber fails for some reason I won't be pulling on the windlass.

Fortress rules in soft mud. Use the mud palms, and set the flukes correctly though.

[Dockhead]

Originally Posted by malbert73

I totally get it about full reverse but I don’t think it generates that much force for me.
I prefer to set the anchor then allow chain to settle and spring boat forward. Then I back aggressively 2-3 times against the catenary until the boat jerks to a stop. I feel I get much more force with jerking back against the chain than static reverse. Plus it’s kind of fun that the Mantus may as well be anchored in concrete for how quickly it stops the boat, especially compared to the CQR I grew up with

I wouldn't do any jerking if I were you. You can break something that way, and it won't do anything good for your anchor set. You need a steady pull which pulls the anchor down into the seabed. If your prop or whatever doesn't generate enough force for that, then I don't know what to tell you. But people without engines set their anchors by backing the mainsail.

[parachute]

Soft mud is not a good place to anchor. The key to stop dragging is the weight of the catenary which takes the load off the anchor.

[BlackHeron]

Slow steady force pulls the anchor down deep. Jerking shock loads pull it up and out. Shock loads are also hard on your bow cleats or windlass/bowroller/bowsprit and are to be avoided.

The whole purpose of a stretchy snubber line is to minimize shock loads. Reducing shock loads is like having a heavier/larger anchor because it is that much harder to jerk out of the bottom.

[Lodesman]

I think my nearest analog to the OP's areas of concern would have been Titusville. We anchored outside of the channel in gusty conditions that had generated a good chop on the ICW. Pointed into wind, put in reverse just above idle, when headway stopped let anchor go, marked plot (CP and AIS), paid out about 100', engine to idle and snub, watch as cable comes taut with no jerks or jumps - to indicate the boat has its cable, paid out another 60' give or take (this is from memory assuming 20' from bow roller to the bottom). No snubber per se - chain secured on deck with 2 shortish, stout nylon strops to the bow cleats with room to stretch a couple feet. Slept like a baby, didn't move an inch. Weighing the next morning was more of a chore than normal - had to wash the mud off the chain, and breaking the anchor (33kilo Rocna) out of the bottom involved securing it at 1:1 scope and motoring against it about half-throttle.