Weaving Back & Forth at Anchor

[GMac]

Simple cone shape. 18" big end down to 6", there abouts. A PVC/canvas type material. All held togeather with webbing. They seem to be a craze at the moment with the fishermen who now drift rather than anchor. Cheap as chips, can be found here for NZ$25. Flowing in out of china I'd say.

Like the photo below. This isn't mine but it's very similar. All soft so packs away to tiny. Come in assorted sizes and pretty colours.

[GordMay]

24" Drift Anchor ($14)
➥ ANTOnline.com - Pragotrade 50-0110-W 24" Drift Anchor

[Agility]

Perhaps a more controversial solution and clearly from my own personal experience. I don't think conventional wisdom would support this theory but math could.

Shorten your scope! My Tayana 58 deck salon would surf like crazy. I would typically use a 3:1 or at times 4:1. My theory was that if the boat was surfing another 10% due to 5:1 scope instead of 4:1 scope then I was more likely to drag because of the increased force on the anchor from the addition speed during the longer and faster arc.

Call me crazy, but I only dragged a couple of times in 18 month of anchoring all around the world and that was in areas where I knew there wasn't good holding. If I could set the anchor at 3:1 with 2,000 RPM's I felt comfortable that it wold reset in a wind shift.

The other observation was that the few time that I drug, it was at the apex of the arc. 33K tonnes at 2-3 knots is a lot of force.

Expectations for my new Atlantic 57 is that she doesn't surf much at all and that more scope actually helps holding dramatically. The the only issue it too much scope for the surrounding boat at anchor, especially those Tayana 57's

[GMac]

Yeap, shortening the scope will also reduce sailing at anchor. But not being a short scope fan myself and having a rope/chain rode I do sleep a lot happier with more out. The only hassle is that sailing which I've now minimised.

But if you do have nice big gear, set it well and conditions permit shortening up is definitely an option.

[nelson.peter]

Agreed. I am of the "long scope" club. If you can sleep with short scope, go for it. I am not one of those people. I err on the side of caution and usually put out more than I have to (unless the anchorage is crowded).

[Reality Check]

It appears we may be attempting to treat swing caused by wind the same way as that caused by wave / current. Not sure the "same" fix is as effective.

On the Wind side of the fix: On the "Drift Anchor", how far below the surface to you attach it? How is it fixed to maintain itself in an Open condition rather than simply that of a wet rag hanging from the chain?

[nelson.peter]

You are correct, Reality Check, that we are talking about a couple different things. Wind swing can be reduced with the drogue. The anchor spring line would be effective against current or other types of effects. Of course, I am just learning all of this myself, with no direct experience, so what do I know?!! But that is how I understand it.

As for deploying the drogue, one poster noted about 6 feet below the surface, i think. But I think if you get it down far enough so that when the wind comes up, and your rode stretches and tightens it doesn't lift the drogue out of the water, then you should be fine. Closer to the boat, of course, will give it greater impact than if you bury it 5' from the anchor!!

At least that is how I see it coming together.

[GMac]

I think NelsonP has it pretty right and I was the 6ft deep poster.

When out, mine is about the 6ft below water as mentioned to make sure if we do get any speed up with a big gust or similar the drogue does stay well in the water. I also added a few small lead sinkers to assist on that front as well. I made a small strop with 2 hooks on it which the drogue hangs off. One clips to my stem head and the other over the anchor warp and acts more as a sliding ring type arrangement. The rode line sits about 2'6" off my bow, just enough to keep it away from paintwork.

The openings have a polyprop rope sewn in so seems to stay open or opens when required.

There is nothing fancy or anything that costs much bucks about it all really. I'll try and remember to take a photo next time I use it.

Only works with wind caused swinging but I suppose you could tweak the same arrangement to help with tide sometimes.

[Fuss]

I have the same weaving problem and this is my experience...

the riding sail helps a bit but does not fix it.
as swagman says, its not good to have this up in a real blow
I agree that furled sails don't help but i am not removing them everytime I anchor.
I dont like the idea of a stern anchor or a 2nd anchor
I dont like the idea of a 2nd anchor over the bow just dragging on the ground.
I like the idea of anchoring from the stern, but setting this up is difficult and the stern is then exposed to the weather.
I like the idea here from swagman with the drogue but I get the feeling that this might just work a bit, like the riding sail helps a bit.

It would be really great if this made a big difference, has anyone tried it yet?
If so could you report back, as this sounds like the best idea I have heard for a long time.

[lancelot9898]

Originally Posted by john Fussell

I have the same weaving problem and this is my experience...

the riding sail helps a bit but does not fix it.
as swagman says, its not good to have this up in a real blow
I agree that furled sails don't help but i am not removing them everytime I anchor.
I dont like the idea of a stern anchor or a 2nd anchor
I dont like the idea of a 2nd anchor over the bow just dragging on the ground.
I like the idea of anchoring from the stern, but setting this up is difficult and the stern is then exposed to the weather.
I like the idea here from swagman with the drogue but I get the feeling that this might just work a bit, like the riding sail helps a bit.

It would be really great if this made a big difference, has anyone tried it yet?
If so could you report back, as this sounds like the best idea I have heard for a long time.

Agree with your conclusions, but the idea that a drogue would work is doubtful in my mind since its usefulness would depend on the speed that it's pulled through the water. When my boat "hunts" at anchor it goes slowly from one side to another. Even with full gale force winds I don't think the speed throught the water is sufficient to make much difference. When I was anchored in a Cat 1 hurricane...yes then the speed through the water is there, but then a second anchor on a very short scope would probably be more useful in limiting the "hunting". I do see some improvement in the hunting by locking the rudder amidship and by using a short bridle. Not sure if using a short scope in much benefit since a long scope would have more chain on the bottom and offer more drag, however I can understand that argument in that it limits the distance of the arc.

[thinwater]

If I tie my cat by one hull or the center beam it's all over the place. If I use a bridle it's a rock, no matter the thunderstorm.

Make certain the bridle goes from a point far enough back that there is some beam, and extends far enough forward that is well in front of the bow. Give it a good chance to work by studying the geometry. It needs to be able to apply a correcting force as soon as the bow moves.

As for second anchors taking more than a few minutes to set or retrieve, that is a matter of method and practice.
1. Set the primary on VERY long scope (double normal).
1a. If you are a cat, motor to one side using a single engine, in the dirrection of the expected wind shift. If you are a mono, you may have to settle for behind you, since you have a single screw.
2. Lower a secondary off the stern.
3. Lead the secondary rode to the bow, outside the rigging.
4. Pull in the scope on the primary to normal.
5. Pull the secondary in against the primary to set.
6. Let out some more rode on the secondary to achieve the desired angle.
7. Connect the secondary rode to the chain below the roller.

I actually keep 2 set-length rodes so that I attach the end of the rode to the chain - no tangles if the tide rotates! Just disconect and stow.

Retrieving is a simple matter of reversing steps: disconect the rodes, ease the primary back, and pull up the secondary and store it in a stern locker.

This never takes more than 5 minutes up or down.

Practice in calm conditions. I'm sure there is a simple method for every boat. There are 2 tricks: have a set-length rode available so that you do not have to un-twist rodes; ease the primary back so that you can more over to the secondary to retrieve. If the load is really on the secondary due to a wind shift, use a sheet winch through a snatch block. Slower than 5 minutes, but not hard.

[Fuss]

Originally Posted by thinwater

If I tie my cat by one hull or the center beam it's all over the place. If I use a bridle it's a rock, no matter the thunderstorm.

Make certain the bridle goes from a point far enough back that there is some beam, and extends far enough forward that is well in front of the bow. Give it a good chance to work by studying the geometry. It needs to be able to apply a correcting force as soon as the bow moves.

I have tried a bridle on my monohull and it made no difference in my situation.
Using a point further back did not seem to make an improvement and on top of this, the line then rubs on the topsides. It seemed to me that taking the line further back made no change except that the leeward line wrapped around the bow and then proceeded to chafe the paint off.

[Albro359]

I don't have this problem....We have a 7'5" draught fin keel, skeg rudder..relatively flat bottom...40kg plough, all chain rode...which we pay out to the max in most conditions except calm/ lunch stop

never ever rode around the hook...

worst was in a 60 knot gale at Great Barrier Is...maybe we swung about 20 deg +/- ?

Cheers

Alan

[thinwater]

Originally Posted by john Fussell

I have tried a bridle on my monohull and it made no difference in my situation.
Using a point further back did not seem to make an improvement and on top of this, the line then rubs on the topsides. It seemed to me that taking the line further back made no change except that the leeward line wrapped around the bow and then proceeded to chafe the paint off.

Thanks for sharing the information. I suspected as much, though I have heard it suggested.

[Joli]

I think much of this depends on the center of resistance of the underwater profile versus the above water profile. We are rock solid and simple do not hunt, I've seen other boats our size that hunt all over the place so size is not it. As Bash said, cockpit enclosures may help if it moves the center of resistance aft. Or as Swag said stopping the bow from blowing off may help if you do not want to add resistance aft.