DQ...I think Gord May is playing fast and loose with the term since he is the one that wrote what you copied. It is nevertheless descriptive of where the line is affixed to the boat.
Both websters and wiki define spring lines as to docks only and wiki has a nice diagram here:Mooring (watercraft - Wikipedia, the free encyclopedia
Can't find any source other than Gord with this use.
No big deal but would be interesting to know if ANYONE can find a sailing related source like Bowditch (don't have one handy!) which mentions springs in anything other than a docking use as I do like to be correct in my usage.
de Kerchove's International Maritime Dictionary
defines "Spring" thusly:
1. A shore mooring line diagonal to the keel and exerting a force, when power is applied to it, both in the direction of the keel and at right angles to it. It is therefore used for moving a vessel alongside quay or pier ahead or astern, breasting her in at the same time. also called spring line, spring rope
2. Offshore line or hawser made fast at one end to an anchor cable, the other end to the ship's quarter, by which the vessel is handled broadside to the anchor. Also called spring line, quarter mooring.
3. A crack running obliquely through any part of a wooden mast or yard, which renders it unsafe to carry the usual sail thereon. The spar is then said to be sprung.
(all other definitions with spring involved conform substantially with the above definitions according to the usually reliable de Kerchove.)
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