[Public-List] Anchored Stern To

Gordon Laco mainstay at csolve.net
Sun Apr 13 07:19:41 PDT 2008


I am not a hydrodamicist; but would suggest that it would be a very
fortunate circumstance if going full ahead with the rudder hard over
resulted in anything good occuring.

Consider the situation - the rudder with the prop wash blowing on it is a
few feet downwind of the point at which the stern is fixed to the anchor
cable.  The windage on an A30 is all way forward.  I can't see any way the
rudder would be able to lever the boat to windward so long as there is load
on the cable (sort of like pulling up on your boots and hoping to get off
the ground!).

Consider also that while one was vainly trying this another couple of waves
filled the cockpit... And significant amounts of water started getting in
through your lazaratte and cockpit hatches or even the companion way.  You
could be sunk in a few moments.

Better if caught by the stern this way to just cut the line and save the
boat.  Then remember never ever to get into that situation again!  The cost
of an anchor and the lost cable is not much against the consequences!

Cheers - Gord #426








> 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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