[Rhodes22-list] anchoring
Herb Parsons
hparsons at parsonsys.com
Tue Sep 16 14:37:29 EDT 2008
BTW, I DO agree that dumping chain with no set is fruitless.
Bill Effros wrote:
> Herb,
>
> How long ago did you take the class?
>
> If you look at older West Marine catalogs they had diagrams of anchor
> rode showing "catenary curves" in "taut" anchor rode explaining that the
> weight of the chain pulled the anchor parallel to the bottom. Then, one
> year, they explained that their own diagrams were nonsense, and that the
> anchors were designed to be pulled at a 45 degree angle to the bottom,
> and that the notion of "scope" had no validity if the chain could change
> the angle of pull.
>
> I just looked again. The catenary curve diagrams and explanation are
> gone. But the chain lying on the bottom diagram is back, along with the
> straight 45 degree angle of scope.
>
> The recommendation has changed from a flat 6 feet of chain, to 1 foot
> per waterline foot, to the current recommendation of 65 feet of chain
> tied to 200 feet of rope.
>
> The explanation varies from "bottom abrasion" to "Shorter scope."
>
> BUBBA MEISAS! (As Stan's Grandmother would say.)
>
> There is no bottom abrasion if your rode floats. -- It never hits the
> bottom. It never gets dirty except for picking up seaweed.
>
> Scope is scope. The angle is the same whether it is chain or rope.
>
> Dumping 65 feet of chain on a bottom just 8 feet below; never setting
> your anchor, and then wandering around within a 150 foot circle unable
> to determine if your anchor is set or dragging, makes no sense at all.
>
> If you don't have a windlass you don't use the anchor because it's too
> difficult to retrieve and never reliably sets.
>
> Get a $100 2 1/2 lb. guardian. Try it on an all rope rode. Deploy it;
> retrieve it; learn to flake the rode; store the whole shooting match
> under the cockpit seat. Then ask the CG guys to explain to you, again,
> why they recommend what they recommend.
>
> BE
>
>
>
> Herb Parsons wrote:
>
>> Bill will continue to say this is nonsense, and I'm not going to say
>> he's wrong. I AM going to say I think he's wrong. The coast guard
>> captain's class I took went over this, and disagrees with him. Sometimes
>> CG folks continue to do things based on "tradition", but I think in this
>> case, they knew what they were teaching.
>>
>> Bill Effros wrote:
>>
>>
>>> Rob,
>>>
>>> You need chain if your anchor is so heavy you can't pull it up by hand.
>>> Then you need a windlass. The windlasses destroy rope -- they work best
>>> on chain. Everybody makes a lot of money by suggesting that you anchor
>>> better if you have a chain rode, but that is nonsense, and the enormous
>>> weight of the chain in the bow totally throws off the balance of boats.
>>>
>>> In the process, people start drawing diagrams and providing pseudo
>>> scientific explanations that make absolutely no sense when you start to
>>> think about them.
>>>
>>> Then somebody comes up with the 22 feet of chain on the 22 foot boat
>>> rode rule. Which also makes absolutely no sense.
>>>
>>> A modern anchor is not like a cinderblock or an engine block. It does
>>> not just sit on the bottom, it digs in like a railroad spike, and is
>>> designed so it can be easily released by changing the angle of the rode
>>> from the surface. Adding weight does not help it in any way. Modern
>>> anchors are designed to be pulled at specific angles -- mostly around
>>> 45 degrees -- which is what the 7:1 scope accomplishes. Chain sitting
>>> on the bottom defeats the angle of the scope relative to the anchor. It
>>> is counter-productive.
>>>
>>> If you want more weight on your anchor, get a heavier anchor. But there
>>> is no need to do so. A 2 1/2 lb guardian anchor, properly set, will
>>> hold you in place forever. Your rope rode will withstand far more load
>>> than the fittings on your boat.
>>>
>>> Bill Effros
>>>
>>>
>>> Lowe, Rob wrote:
>>>
>>>
>>>
>>>> Bill,
>>>> So why does everyone (well, most everyone) suggest using chain on the
>>>> rode? - rob
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: rhodes22-list-bounces at rhodes22.org
>>>> [mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of Bill Effros
>>>> Sent: Tuesday, September 16, 2008 10:59 AM
>>>> To: The Rhodes 22 Email List
>>>> Subject: Re: [Rhodes22-list] anchoring
>>>>
>>>> Ben,
>>>>
>>>> In order to set the anchor you must put tension on it. This pulls the
>>>> rode taut. When there is no wind or current, the rode will lie flat on
>>>> the bottom, or float to the surface if it is a floating rode. But it is
>>>>
>>>> not holding the boat in place.
>>>>
>>>> What most people call "dragging the anchor" is usually "dragging the
>>>> chain". If you fail to set your anchor -- which you will fail to set
>>>> properly if you never draw the rode taut -- you can drag the chain all
>>>> over the place, without ever properly setting the anchor. If you draw
>>>> the rode taut and properly set the anchor it just won't drag.
>>>>
>>>> A very small anchor can be used to hold a very large boat in place if
>>>> the anchor is properly set. It is much easier to set an anchor with an
>>>> all rope rode. The chain portion of the rode does not change the angle
>>>> of pull.
>>>>
>>>> Bill Effros
>>>>
>>>>
>>>>
>>>>
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>>>>
>>>>
>>>>
>>>>
>>>>
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