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In the same boat as you with a mixed anchor rode, 50' of chain and 200' of 5/8" 3 strand rope, fairly high free board and we sail at anchor.

Have a number of things I do to reduce (wish we could eliminate) the yawing and each one helps to a degree.
  1. Use a snubber, at present about 25' of 3 strand using an anchor hitch to the bow cleats on each side. Use if on chain or rope and depending on depth and amount of rode out. This puts the connection point lower than the anchor roller and helps with 2 spread out attachment points.
  2. Put up the riding sail on the topping lift, cuts down sailing even more.
  3. Take the dinghy off the front deck (in front of mast) reducing windage forward.
When I first has the boat only had 20' of chain and on adding addition chain noticed it was a lot better with the added weight. Wish I had even more...

Jeff
 

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A perceptive question.

Yes, they do increase windage, but only a small amount compared to the windage reduction from keeping the boat better aligned. Even more importantly, perhaps, is that the anchor is not pulled from side to side. The increase is about 5-15% and the reduction in total windage is typically 25-50%. Lot of variables, including how much the boat was yawing to begin with.
PS review
Thank you, makes sense.

Also thanks for the link, although I can't get in and can't even reset my password. PS believes that my account name is invalid, even though it has not changed for 15 years (and the subscription is paid up, of course). Have to deal with that another time.

EDIT: Just seeing in my paper copy that there is an additional article on 'Yawing and Anchor Holding" in PS from February 2020. Clearly an active topic!
 

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Question...
Has anybody tested a short drouge/sea anchor tied to the stern to learn if it can alleviate the swing
In fact many have. I'll have an article out in a few months (still testing). Logically, it works better on the bow (that is where the swing starts). Additionally, it works best on boats that are very active sailors, because it does not apply a correcting force until the boat is already moving.

It can also dampen hobby horsing, but that is more complicated.

Try it on your boat. You'll need about 2-pounds to hold it down and to get it to pass safely under the bow (remember, it will be angled sharply aft). Start with about a 2-foot drift cone and see what works for your boat. A string of buckets can work (one is probably not enough). But I think you will find there are more effective methods.
 

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why do people care if it swings on the anchor ?
a. Swinging will loosen the anchor in the bottom, increasing the chance of dragging. This is a leading cause.
b. Swinging typically doubles the tension on the anchor rode, because the wind and waves now see your boat from the side.
c. You take up more room in the anchorage.
d. It's annoying sometimes. It is always annoying to the other boats, because they don't know when you are going to sail the anchor out (see a and b).

A little swing, up to about 30 degrees is normal and harmless. The wind changes dirrection. More than that is a problem, becomeing very serious past about 60 degrees.
 

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a. Swinging will loosen the anchor in the bottom, increasing the chance of dragging. This is a leading cause.
b. Swinging typically doubles the tension on the anchor rode, because the wind and waves now see your boat from the side.
c. You take up more room in the anchorage.
d. It's annoying sometimes. It is always annoying to the other boats, because they don't know when you are going to sail the anchor out (see a and b).

A little swing, up to about 30 degrees is normal and harmless. The wind changes dirrection. More than that is a problem, becomeing very serious past about 60 degrees.
Got it, makes sense. Sounds like references to extreme swinging. I just assumed that this subject comes up a lot with people who are moving around a little on the anchor and being overly concerned about it. We sway a little on the anchor, but its mostly just moving the boat back and forth a small amount and the rode stays in the same general direction. Never noticed being substantially out of sync with other boats anchored near by. I’m curious about the physics of how a boat would sail off enough to pull the anchor out assuming you had plenty of rode out? Seems like the wind would always keep you more or less in the same general drirection?
 

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Got it, makes sense. Sounds like references to extreme swinging. I just assumed that this subject comes up a lot with people who are moving around a little on the anchor and being overly concerned about it. We sway a little on the anchor, but its mostly just moving the boat back and forth a small amount and the rode stays in the same general direction. Never noticed being substantially out of sync with other boats anchored near by. I’m curious about the physics of how a boat would sail off enough to pull the anchor out assuming you had plenty of rode out? Seems like the wind would always keep you more or less in the same general drirection?
Generally swing is not that extreme. But if...

1. Excess windage forward. Dinghy on the bow, reacher on sprit, or just high fore cabin or a lot of freeboard forward.
2. Fin keel fairly far back.
3. Large rudder.
3. Rope rode (chain damps swing).

... the swing can reach over 100 degrees and I have seen boats sail the anchor out in 15 knots. The basic cause is having the center of windage too far forward of the center of lateral resistance. If I use a bridle my boat barely swings. If I skip the bridle, lift the centerboard, leave the reacher up, and leave the rudder down, she will yaw over 100 degrees and can sail the anchor out. I've seen boats yaw at several knots.
 

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It seems to me that a boat will respond to a wind shift. (let's leave out current for the moment). When the wind shift... the wind "sees" one side of the boat... and it pushes on that side.... moving the boat and probably cause some rotation about the bow roller where the rode leave the boat for the bottom. The lateral motion will cause the rode along with the boat to move to the lee a bit. But the boat being a streamline shape will weather cock aligning with the wind. But it has moment so it can move past alignment with the wind. The the process repeats in the opposite direction. It's really a matter of wind force and the momentum of the boat... and that is also dependent on the keel and the lateral resistance of the underbody/keel. Chain on the bottom will move less than a nylon rode. The yaw motion is very much based on the location of the center of the lateral plane of the boat. A wind vane has the C of the LP well aft of the pivot point.... and that prevents it from yawing back and forth in the wind. A boat has an above the water lateral profile and a below the water profile. The mass move through two different mediums... air and water. So the lateral plane in the water tends to damped the motion of caused by a wind shift or misalignment with the CL.

The anchor sail moves the lateral center above the water aft.... making the boat behave more like a wind vane. Motion is a the result of all the forces... resisting water, lateral plane above and below the water and the force of the wind. More wind imparts more momentum to the boat and the motion is exaggerated. Of course the wind is not generally steady in force or directions and these also can induce movement.
 
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