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Old 06-29-2014, 05:37 AM   #1
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Power setting the anchor

I've been following a thread on the cruising forum website about how much power to use in reverse to set the anchor. Most on this site have yachts and they say they use near full power for a few minutes after setting the anchor to really dig it in and prove it will hold in a strong blow.
My question to you all is, how do you set your anchor and how much power do you use to power set the anchor.
My boat is a Grand Banks42 with a Rocna 40 KG and 100 metres of 10mm chain.
I drop anchor then move back slowly paying out 6 x scope then pull back to put tension on the chain till it's straight then I relax it the gently reverse till it's tight and keep the boat in reverse on one engine at tick over while feeling the chain and taking a transit. If it hold still for 30 seconds I relax the pull and then bring it under tension again. If it still passes the 30 seconds test I add the second engine also at tick over and hold this for one minute. If the chain feels solid and the transit is good then job is done and I add the nylon snubber.
Do any of you experts out there use more power than I do to set your anchors?

Brian

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Happily cruising Croatia as we speak.
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Old 06-29-2014, 05:54 AM   #2
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I forgot to add that I adjust the scope after setting to suit the anchorage and weather but normally use 5 x distance from anchor pulpit to sea bed.

Brian
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Old 06-29-2014, 07:03 AM   #3
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Your procedure is sound and should work in most conditions. When the chain gets straight under moderate power and you aren't moving then you know the point of the anchor is digging in. Any subsequent wind force (in the same direction) will bury it further.

The downside to digging it in really deeply is if the wind shifts then that deep anchor has to work its way around to the new wind angle. Since wind shifts like this often are accompanied by stronger winds, I would prefer the whole process starts with the anchor partially buried so it can twist around easier.

The only time I would power down hard on the anchor is when I was already in high winds and in that case they tend not to shift.

You will know how much power to use in forward to balance the wind as you move forward to set the anchor. Most boat props are half as efficient in reverse so maybe use 50% more rpm than that to set it hard.

A GB 42 which is likely to have twin 135 hp Lehmans will pull quite a force at full reverse power. That will bury the anchor very, very deep if it holds.

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Old 06-29-2014, 07:05 AM   #4
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No Ice, for a Rocna, that's plenty. Some older anchors like the CQR types need a harder pull to be sure (personal experience), but the newer roll bar types will usually just set with enough reverse to lay the chain out and a gentle tug. I often don't even bother with that if there is a bit of wind or current, but just let that set the anchor. Works for me...
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Old 06-29-2014, 07:13 AM   #5
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Identical arrangement, 40 kg Rocna, 3/8" chain. Generally we are 5-6 to 1 on the scope, in 30 ft depth we let out 200-250 ft of chain.

We let the usually good winds (15kt +) settle us in for a couple of minutes and then power down at 1200 rpm on a single Lehman 135.
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Old 06-29-2014, 10:28 AM   #6
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Originally Posted by No Ice View Post

I've been following a thread on the cruising forum website about how much power to use in reverse to set the anchor. Most on this site have yachts and they say they use near full power for a few minutes after setting the anchor to really dig it in and prove it will hold in a strong blow.

Hard to wade through some of the apples and oranges over there, sometimes. A sailor using "full power" might be talking about 32-hp. If I used "full power," that'd be 900-hp. I think you're right to break it down into smaller pieces.

-Chris
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Old 06-29-2014, 10:37 AM   #7
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In decades of anchoring on both coasts I have never backed down as hard as some say.

I've had them fail to set but once set they seem to stay. Of course I use lots of chain and scope.
After you really bury them what do you do when the current or wind changes direction at 2AM?
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Old 06-29-2014, 10:49 AM   #8
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sleep tight...what happens during a hurricane that passes nearby?

your anchor gets buried as deep as it probably ever will and then the wind changes nealy 180 degress for the second greatest pull it ever gets...

anchor manufactures and so many anchor enthusiasts claim their anchor will hold in that kind of blow....so...what's gonna happen?

I would hope all but Danforth style anchors have a shank that will only bend at some force greater than the normal breakout pull anyway.

I like to anchor in places and/or situations that my chain holds me...the anchor is just there for show....
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Old 06-29-2014, 11:01 AM   #9
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Your setting method seems sound to me Brian.
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Old 06-29-2014, 11:03 AM   #10
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[QUOTE=psneeld;245949

I like to anchor in places and/or situations that my chain holds me...the anchor is just there for show....[/QUOTE]

You must be doing your cruising in swimming pools.
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Old 06-29-2014, 11:26 AM   #11
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How do you secure the chain(with an all chain rode) while backing down? Do you use the windlass or snub off with another line? Where I do a majority of my anchoring, Once the anchor starts to set with wind and/or current, I snub it off and have never had a drag problem. I am in NE FL with mostly hard sand with a 60lb CQR and all chain.
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Old 06-29-2014, 11:55 AM   #12
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I set my anchors at 1400rpm in reverse w a 40hp 30' boat. The rode "seems" quite tight to me and I'm always on the bow to pull on it to check. I pull on the rode/line at right angles halfway between the bow roller and the dedicated anchor cleat.

I have read and heard many times the best way to set an anchor is to do it very slowly. Some call it "soaking" the anchor. Also it seems quite obvious to me that the higher the performance of the anchor the less setting needs to be done. If your anchor is 100% dependable you should not need to set it at all. No such anchor exists of course. But setting is actually, IMO a test of the bottom and not the anchor. That may or may not be true if the anchor dosn't set. Could be the bottom and could be the anchor. You can go find another anchor or go find another bottom. But if you've got a good bottom and an anchor that sets well setting the anchor would be somewhere between not very important to largely a waste of time. However the bottom is the biggest anchoring variable. But if I knew a blow was coming and I had a small Claw anchor I'd set it slowly and as deeply as I could.

Perhaps a more important thing re deploying an anchor is laying the anchor and rode out. If you just dump the whole thing on the bottom all sorts of things can go wrong. When the anchor touches bottom I stop feeding out line. I signal my wife at the helm to back down. After way starts she does that by occasionally bumping reverse by my direction as I watch the water and sense speed and at the same time considering the tension on the line. When way starts I feed out rode as slowly and as closely as I can to lay the rode down in a straight line. When setting scope is reached I have Chris bump the power to slowly and gently at first take the slack out of the rode. Also I hold the line in my hands while standing and feel the "texture" of the bottom. Some anchors set so quickly this step ins not possible as no dragging of the anchor takes place. I slowly (or in some cases very slowly) increase tension until 1400rpm is reached. If it needs anymore setting that that the wind should do fine and the wind sets an anchor best ..... slowly.
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Old 06-29-2014, 12:06 PM   #13
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Also I hold the line in my hands while standing and feel the "texture" of the bottom.
I know you mean laying your hand on the rode after it's been tied off to feel if the anchor is bouncing along the bottom, but I can't shake my image of you with one foot on the bow, the rode wrapped around your forearm whilst your heartiest pirate laugh echos throughout the anchorage.
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Old 06-29-2014, 12:23 PM   #14
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Brian, every thing sounds ok except I would use the snubber while setting the anchor. I don't want that much load on the windless.

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Old 06-29-2014, 01:00 PM   #15
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Brian, every thing sounds ok except I would use the snubber while setting the anchor. I don't want that much load on the windless.

Shay
Right. Also if there is a bow anchor pulpit there will be a tremendous load applied to it. It is much better to transfer the load to a cleat or eye with a good backing plate.
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Old 06-29-2014, 01:07 PM   #16
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HAHA Murray ..

I do it very slowly wearing gloves. When the anchor actually begins to set I quickly loop the line around the big cleat and stop the boat.

I'll work on the pirate laugh.
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Old 06-30-2014, 12:02 AM   #17
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Idle power usually will suffice.
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Old 06-30-2014, 12:58 AM   #18
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I lay out the anchor and chain as I drift back so it doesn't pile up. Then when I reach the desired ratio, I first let the current set it and stop the boat. After a few seconds, I set it with idle reverse power from twin 85 HP Perkins.

We anchor in 15-50 feet of water, mud bottom with great hold on a claw anchor. 120 ft of chain, the rest rode. Since we don't set with lots of power, we do it on the windlass, then secure the line/chain via cleat and snubber.
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Old 06-30-2014, 01:00 AM   #19
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We just idle in reverse 'til the slack in the chain is gone and the GPS speed shows zero. Give it a bit if throttle for a couple seconds and verify the speed is still zero. Put the snubber on, shut the engines down, and break out a cold one.
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Old 06-30-2014, 04:48 AM   #20
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Thanks to you all for your input. To answer the question, do I set the anchor using a snubber to remove the load off the windlass, the answer is no but I take the point and will in the future.
I also should have added to my opening question that I have two 315 HP Cummins engines so that's why I use tick over revs to power set the anchor.
Does anyone with similar sized engines use more power than this?

Brian.
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