Mar 6, 2013, 8:27 AM
Post #5 of 12
Tue, 05 Mar 2013 20:50:13 -0800 (PST)
Re: [The Publisher] Displacement of an anchor
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Date: Tue, 5 Mar 2013 20:50:13 -0800
Subject: SCUTTLEBUTT 3789 - Wednesday, March 6, 2013
From: Bill Barham
To the question, "Does anchoring cause the sea-level to be (a) higher, (b)
lower, or (c) no change", the answer is (b) lower.
First consider that FLOATING things displace a volume of water EQUAL to
their mass. The anchor sinks because when it's in the water, it displaces
LESS volume than the water it's competing with. So while the anchor is in
the boat, it's displacing MORE water than the anchor's volume. So tossing
out the anchor, the anchor now displaces water EQUAL to the anchor's
volume, so the sea-level FALLS by that difference in volume.
Corollary: if civilization is in danger because climate change will cause
seas to rise, we all need to go out and anchor to compensate.
This would be true if anchoring with no wind and no current (but then, why anchor, just drift)
When anchoring with those horizontal forces in place, the boat is subjected to both horizontal and vertical forces based on the scope of the anchor rhode. It is quite likely the downward component would exceed the anchors weight, and the net result will be an increase in effective displacement. Thus, the sea-level would increase.