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Old 07-29-2013
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A (stupid?) anchoring question

Does anyone out there ever use two anchors from the bow? I am just imagining trying to anchor and not drag in heavy winds and/or current. My 3000 lb displacement boat should be OK with my 16lb Bruce anchor and 15 ft chain and 200+ft of rode. But I also have a smaller Danforth with just rode (no chain). As extra "insurance" would it ever make sense to use both and tie them off to the bow?
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Old 07-29-2013
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Re: A (stupid?) anchoring question

It's called Bahamian Mooring:
Anchoring with Two Anchors, Bahamian Style Mooring | Tropical Boating

p.s.: "There are no stupid questions, only stupid answers." ---Carl Sagan
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Old 07-29-2013
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Re: A (stupid?) anchoring question

The only thing that is stupid is NOT asking the question you don't know the answer to.
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Old 07-29-2013
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Re: A (stupid?) anchoring question

You can run two anchors on the same rode, or two anchors in different rodes. Both will increase holding power, but both also can cause significant issues.
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Old 07-29-2013
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Re: A (stupid?) anchoring question

Quote:
Originally Posted by matthewwhill View Post
Does anyone out there ever use two anchors from the bow? I am just imagining trying to anchor and not drag in heavy winds and/or current. My 3000 lb displacement boat should be OK with my 16lb Bruce anchor and 15 ft chain and 200+ft of rode. But I also have a smaller Danforth with just rode (no chain). As extra "insurance" would it ever make sense to use both and tie them off to the bow?
This is like all anchoring threads, very contentious and there will be some saying the ideas of others are rubbish and the only way to do it is theirs. My ideas follow and you can take them with as many grains of salt as you desire.

A Bahamian setup is used more where conditions are relatively benign but tides oscillate back and forth - not really a solution for anchoring in extreme conditions.

Anchoring with two anchors on two rodes requires that the anchors be set with the rodes in a V, in other words set one anchor, motor up to the first anchor and then across at right angles to the wind then deploy the other anchor and get it set. The boat then drifts back and both anchors should hold. It is however quite difficult to get the second anchor to set.

Also I have found that when the boat swings back and forth which it will always do, it loads up the left anchor then the right and rarely does it actually apply load to both anchors. If the wind is blowing hard, as each anchor gets loaded it may/will drag a little. As this happens, the anchors don't drag backwards, they drag towards each other. If they continue to do this they will eventually start interfering with each other and then the whole system fails. That's been my experience and as said earlier, there will be many who disagree.

My choice is a tandem anchor setup where you would set one anchor and let it bury itself. Then shackle the front of a second anchor to the chain about 30 metres from the first anchor, motor forward and across at about 45 degrees. Halfway to the first anchor, deploy the second anchor and set it. It will almost always set before the first chain goes tight. As the load comes on it will either hold or it will continue to dig until the front chain goes tight. Then it will stop.

The advantage of this is that when the boat swings from side to side, it will cause the second anchor to turn as anchors do but no matter how much it turns, the front anchor will continue to hold. If the back anchor drags it will only do so until the chain is straight and tight and then it stops.

How effective is this? Well, we anchored in the Pungwe River in Beira (Mozambique) where the river and the ebbing tide serve up sometimes 6 knots of current and with 30 knots of wind in the same direction as well, we sat on the above setup for four days and never dragged at all.

The best way to decide which system works for you is to try them. I accept no responsibility if the tandem anchors don't work for you. Make sure you know how securely you're anchored.
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Old 07-29-2013
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Re: A (stupid?) anchoring question

Omatako....I can't picture the setup you describe. Might just be me. But could you clarify it a bit?
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Re: A (stupid?) anchoring question

What Omatako is describing:
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Re: A (stupid?) anchoring question

I just have one anchor even in storms. The last thing I want is a difficulty if I need to buzz off fast.
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Old 07-29-2013
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Re: A (stupid?) anchoring question

One good anchor, somewhat bigger than what your boat supposedly needs, seems like the easiest option. That is what I use, but I have no experience with big boats.
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Old 07-29-2013
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Re: A (stupid?) anchoring question

Quote:
Originally Posted by RainDog View Post
You can run two anchors on the same rode, or two anchors in different rodes. Both will increase holding power, but both also can cause significant issues.
Not quite true. See below.

Quote:
Originally Posted by Omatako View Post
A Bahamian setup is used more where conditions are relatively benign but tides oscillate back and forth - not really a solution for anchoring in extreme conditions.
Bahamian moors work well in even sporty conditions when currents reverse regularly.

Quote:
Originally Posted by Omatako View Post
Anchoring with two anchors on two rodes requires that the anchors be set with the rodes in a V, in other words set one anchor, motor up to the first anchor and then across at right angles to the wind then deploy the other anchor and get it set. The boat then drifts back and both anchors should hold. It is however quite difficult to get the second anchor to set.
The configuration doesn't have to be a V. In fact, properly speaking a Bahamian moor is specifically one in which the two anchors are laid in opposite directions so that one anchor holds the boat against the current in reversing conditions.

The V configuration is commonly used to provide greater holding in the face of weather. Personally I like the "get a bigger anchor" approach but not everyone agrees.

Quote:
Originally Posted by Omatako View Post
My choice is a tandem anchor setup where you would set one anchor and let it bury itself. Then shackle the front of a second anchor to the chain about 30 metres from the first anchor, motor forward and across at about 45 degrees. Halfway to the first anchor, deploy the second anchor and set it. It will almost always set before the first chain goes tight. As the load comes on it will either hold or it will continue to dig until the front chain goes tight. Then it will stop.
Correct description of tandem anchoring. The literature does not support the practice. US Navy studies indicate holding is reduced by using tandem anchors. There are a lot of variables and I don't have a copy of the study at hand. I do have Alain Poiraud's
The Complete Anchoring Handbook: Stay Put on Any Bottom in Any Weather: Alain Poiraud, Achim Ginsberg-Klemmt, Erika Ginsberg-Klemmt: 9780071475082: Amazon.com: Books The Complete Anchoring Handbook: Stay Put on Any Bottom in Any Weather: Alain Poiraud, Achim Ginsberg-Klemmt, Erika Ginsberg-Klemmt: 9780071475082: Amazon.com: Books


as well as Earl Hinz' seminal if somewhat dated tome. Both advise against tandem anchoring based on both studies and empirical data.
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