Old as Dirt!
Join Date: Nov 2008
Location: Tampa Bay Area
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For what it's worth, if one intends to do an analysis of a lifeline arrangement, one must look at the entire cable system, from end connection to end connection. In most cases, lifelines terminate at pulpits at the bow and stern although on some smaller yachts, they may angle downward from the last fore’n aft stanchion to deck fittings near the bow and stern. For the most part, stanchions are not intended to take horizontal loads (in bending) but rather to simply to hold the lifelines in position at height and take vertical loads much as do the struts in a tent or the spreaders on a mast. When a load is thrown against the lifeline from inboard, it will move outward and tension up just as does a bow-string when the bow is drawn. The tension in the line is carried by the connections at the bow and stern pulpits. Any loading out of plane is carried by the stanchions acting as struts, hence a little “flex” at the top of the stanchion is desirable. Accordingly, however, one wants tight lifelines so that there is as little “give” or horizontal displacement in the lines before they are tensioned.
Where lifelines and stanchions may fail is with an inward pull rather than an outward push as the lines generally follow the curvature of a hull and hence cannot go into tension when loaded inward. An inward push on a stanchion can seriously load up a base with “prying action” and can easily damage a deck. (I vigorously oppose anyone grabbing or pushing on a stanchion when we're moving the boat about by hand in a marina!)
"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."