[Rhodes22-list] Day Sailors Can't Anchor

Bill Effros bill at effros.com
Fri Jan 13 00:50:22 EST 2006


Phil,

I generally sail on weekdays.  There are a lot of fishermen out in small 
power boats at that time.  I got interested in anchoring from watching 
them.  Even though I was pretty sure few of them could describe the 
properties of catenary curves, it seemed to me that they were much 
better at anchoring than the captains in their fancy yachts who show up 
in our harbor every weekend.

If forced to describe the anchoring philosophy of the simple fishermen 
with an acronym it would be KISS.  They seemed to be just tying  some 
rope to an anchor, and using light weight anchors so their wives or girl 
friends could haul them up from the bow while they stay at the controls.

Bill Effros



pawyrick at peoplepc.com wrote:

> Hi all,
> Great fun watching the debate. I know nothing about physics and just 
> learning about sailboats. I know from experience that with a Danforth 
> style anchor, they can be set in even strong current, with or without 
> chain, if the bottom is right. Being a long time powerboat guy, from 
> 10 to 42 feet, I prefer the chain, particularly if I'm going to be on 
> the hook for an overnight. If I'm just fishing, it doesn't matter much 
> to me. Without the right bottom, plan to drag all over the place, even 
> when the physics is right.
> Phil
> ----- Original Message ----- From: "Bill Effros" <bill at effros.com>
> To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
> Sent: Thursday, January 12, 2006 11:43 AM
> Subject: Re: [Rhodes22-list] Anchoring -- Phuzzy Physics
>
>
>> Dave,
>>
>> I, too, have read the "horizontal pulling force" theory of anchor 
>> rode chain.  As soon as you think about your mechanics and physics, 
>> you will know that it's rubbish.
>>
>> When your boat pulls your anchor into the bottom, the anchor rode 
>> becomes taut.  The angle of the rode is exactly the same whether or 
>> not you have any chain between the anchor and the point on your boat 
>> where the rode is tied off.
>>
>> The anchors we use dig in properly at an amazingly wide range of 
>> angles. Horizontal is not one of them.  Vertical is also not one.  
>> That's what the whole notion of "scope" is about--putting the rode at 
>> the proper angle to cause the flukes to dig in.
>> These anchors set properly despite the fact that people put chain in 
>> their rode, not because of it.
>>
>> Bill Effros
>>
>>
>> DCLewis1 at aol.com wrote:
>>
>>> Bill,
>>> There’s no way I’m an expert at anchoring, but I do know a bit about 
>>> mechanics and physics. You’re certainly right about an anchor’s 
>>> generally sinking, but the chain rode issue may be about  how the 
>>> anchor engages the  bottom, and stays engaged with the bottom -  not 
>>> about sinking the anchor.  Consider an anchor on the bottom with 
>>> sufficient chain rode, if there is a pull from the anchor line with 
>>> any vertical component, the weight of  the rode can counteract the 
>>> effect of the vertical pull and ensure  that forces on the anchor 
>>> are horizontal (i.e. notionally parallel with the bottom).  I 
>>> believe anchors are really made to deal with  horizontal forces; the 
>>> anchoring effect is achieved primarily by flukes, plows, or other 
>>> appurtenances optimally engaging the bottom, and that requires 
>>> horizontal forces.  Without the rode, any substantial pull on  the 
>>> anchor line that has a vertical component may cause the anchor to 
>>> lift  vertically, in which case it may not engage properly, or at 
>>> all, with the  bottom.
>>> Dave
>>> __________________________________________________
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>>>
>>>
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>
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