[Public-List] Anchored Stern To

Robert Kirk isobar at bcpl.net
Fri Apr 11 14:39:33 PDT 2008


At 10:10 PM 4/9/2008, Mike Lehman wrote:

>Then there was the time I was anchored (single-handed) in the middle of 
>the Chesapeake in 107' of water as a stake boat for the Canadian Races. 
>The wind was 30+ out of the north and the waves were 6 feet. I went to 
>pull up the turning mark over the stern  and the rode for the 
>mark  slipped and wrapped around the stern cleat. I was anchored stern to 
>the waves. To free up slack, I had to put the engine in full reverse, 
>directly into the weather, to get enough slack in the line. With me 
>standing on the lazerette, a large wave broke over the stern pulpit into 
>the cockpit. I looked around and the cockpit was full to the bridge deck. 
>I started to ask "what the hell am I doing out here". All turned out fine, 
>I lived and the boat did not sink.

Interesting situation, Mike; it's astonishing how many different ways you 
can have a problem in a boat.

I wonder what would have happened if you had motored *forward* with full 
rudder to  try to come about into the wind to get your slack? A couple of 
things might happen:

1. The engine plus wave force breaks the anchor loose, in which case you're 
fine.

2. The turning moment of the rudder gets you around and you get your slack.

3. You're only able to turn part way until the wind & waves stop the turn, 
you get pounded and broach?

I ask the resident hydrodynamicists to analyze this: How much turning 
moment can a rudder constrained by a line on the quarter produce? What's 
the moment of a 30kt wind vector from the side on an Alberg's 
freeboard?  Mike, J, anyone?

Bob Kirk
Isobar 181


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