[Rhodes22-list] anchoring

[ben]

I know I'm not going to convince you, but if you put out more than 1.5:1
scope, you're making your angle lower than 45 degrees.  If the rode is taut
and you have 6:1, the rode is going to pull up at about a 10 degree angle.
That's what you want for holding.

True, it's probably overkill in lots of situations, but tides rise, wind and
currents change, etc.  Chain keeps that angle lower, so you get more holding
power from less rode.

Ben

-----Original Message-----
From: rhodes22-list-bounces at rhodes22.org
[mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of Bill Effros
Sent: Wednesday, September 17, 2008 10:12 AM
To: The Rhodes 22 Email List
Subject: Re: [Rhodes22-list] anchoring

Ben,

Setting anchors has nothing to do with triangles -- I made reference to 
a single angle.

I am not suggesting short scope.  I set with very long scope utilizing a 
45 degree angle or less.  Because the surface of the water is 
essentially parallel to the bottom, you can look at the angle at the 
surface to understand the approximate angle of pull on the bottom.

Like you, I have discovered the problem with properly set Danforth 
anchors is releasing them, even when you are almost directly above them, 
once they are properly set.

Bill Effros

PS -- The Standard Issue R-22 Anchor looks pretty, but is a lousy 
anchor.  The cladding defeats the purpose of the flukes.  A Fortress 
will exactly fit, but it rattles.  I always anchor from the stern, 
anyhow, so I just leave my pretty blue anchor in place hoping someone 
will steal it someday.  So far, no luck.





ben wrote:
> Yeah, Bill is wrong on this one.  Think about it.  45 degrees is
essentially
> putting out 1.5 times as much rode as the depth you're anchoring in.
(Draw
> it -- it's a right triangle with the anchor rode as the hypotenuse).
>
> I've never seen any article or source recommend less than 5:1 scope.  
>
> But more importantly, I use the standard issue R22 danforth in mud all the
> time.  I overnight in gunkholes or bayous regularly in the spring and
fall,
> and in summer, I drop the hook mid-lake so I have the boat as a big swim
> platform.  Everything you read is right.  The more rode I put out, the
> better it holds.  If I put out 10:1 or 12:1 -- which I sometimes do
> overnight if there's current or wind -- it's darn tough to pull out the
> anchor, even once I'm directly above it.  Many times, I've had to use the
> winch to break it out of the mud.
>
> Maybe other anchors and bottoms are different, but I'll go with the
> literature on this one, because I know it's correct.
>
> Ben S.
> R22 Velvet Elvis
>
>
> -----Original Message-----
> From: rhodes22-list-bounces at rhodes22.org
> [mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of John Lock
> Sent: Wednesday, September 17, 2008 9:02 AM
> To: The Rhodes 22 Email List
> Subject: Re: [Rhodes22-list] anchoring
>
> At 11:52 PM 9/16/2008 -0400, Bill Effros wrote:
>   
>> The point is that the anchor most of us use is designed to set by being
>> pulled at a 45 degree angle from the bottom.  If you pull it parallel to
>> the bottom it just stubs its flukes along and never sets properly.  And
>> if you have too much chain, you can never pull it at a 45 degree angle,
>> so it will never set at all.
>>     
>
> Let me jump in and say I have to disagree with Bill here.  As I 
> understand the physics of the Danforth-style anchors, they actually 
> depend on a certain amount of horizontal (or parallell) movement to 
> get the points of the flukes to dig in.  Here's why...
>
> With the flukes hinged at the back of the anchor and free to rotate 
> about that axis, their mass, pulled downward by gravity, will have a 
> natural tendency to rest directly on the points.  Consequently, an 
> initial horizontal movement will naturally force the points downward 
> and into the mud.  Pulling up on the rode at a 45-degree angle will, 
> in fact, help defeat the design by not allowing the mass of the 
> flukes to perform their downward deflection.
>
> The main reason a few feet of chain helps an anchor set is that the 
> extra weight helps keep the initial movement of the anchor more 
> horizontal, because the rode will begin to rise before the chain 
> does.  This helps the flukes get their initial "traction".  Once the 
> points dig in and force continues to be applied the rode and chain 
> can rise and increase to the 45 degree angle that is ideal to finish 
> and maintain the set.  It's those first few inches of movement that 
> are critical to the set of the anchor.
>
> Cheers!
>
> John Lock
> ~~~~~~~~~~~~~~~~~~
> s/v Pandion - '79 Rhodes 22
> Lake Sinclair, GA
> ~~~~~~~~~~~~~~~~~~
>
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