[Rhodes22-list] Anchoring -- Phuzzy Physics

[DCLewis1 at aol.com]

Bill,
 
I’d prepared a long winded discourse regarding the forces on anchors, etc,  
but when I signed on I saw you were being assailed on all sides, so let me back 
 off and just state what I think are the core issues.  
 
The whole point of a metal chain anchor rode is not to help the anchor  sink. 
 The whole point of a metal chain anchor rode is to help set the  anchor, it 
may also help keep the anchor set.  
 
It seems to me that what’s going on at the boat end of your rode is of no  
consequence for anchoring.  I think all the forces and angles of interest  for 
freeing and setting an anchor are at the anchor shank.  The flukes,  etc, will 
adapt, but to set the anchor you need to get the shank within it’s  operating 
range, and in my limited experience that’s always more horizontal than  
vertical.
 
Everything else being equal, the additional weight of chain rode adjacent  to 
the anchor shank will offset vertical forces coming down from the anchor line 
 and allow the anchor shank to be more horizontal.  In many quiescent cases,  
the weight of the metal chain will actually eliminate any vertical force on 
the  anchor shank entirely, all the forces to the anchor will be horizontal so 
the  shank can be horizontal - that's optimal. Again, more horizontal is good 
when it  comes to setting and holding.
 
Bottom line - anything which helps keep the anchor shank horizontal or more  
horizontal is a good thing.  A metal chain rode attached to the shank does  
that.
 
Now, you CAN achieve much the same effect by letting out a lot of scope -  
but it’s not uncommon to be constrained so that you can’t let out a lot of 
scope  - but in no case will having a chain rode hurt you in terms of setting and  
holding.  So use chain rode, and carry enough anchor line, the two may get  
you through.
 
Like you, I’ve anchored without chain rode, but I’ve also had problems on  
occasion.  I think it was because the anchor shank was too high,  I  think 
chain rode would have helped.
 
I’ll be very interested to see the results of the anchor tests.
 
Dave