Lesson from the past: Sometimes it’s good to have a breaking point, at least in a ship
If the Sept/Oct issue of "Wooden Boat" hasn’t yet arrived in your mailbox, there’s a surprisingly interesting interview with an expert in traditional ship rigging.
If the September/October issue of Wooden Boat hasn’t yet arrived in your mailbox, there’s a surprisingly interesting interview with an expert in traditional ship rigging.
Stay with me here. Jens Langert, who has devoted his life to studying pre-industrial means of rigging, notes midway through the article that sometimes when old designs don’t make sense, it is because they contain a lesson. For example:
Our computers allow us, for example, the see that a topgallant mast of a three-master like L’Hermione, sized according to longstanding scantling rules, will break at 30 knots of wind. One might be tempted to reinforce this mast — to use thicker shrouds and yards to make it more solid. Except … that it is wise and prudent to reduce sail and to brail before the wind reaches 30 knots. If an unforeseen gust, a strong one, strikes the ship when the topgallant sail is set, yes, it’s true, this mast will break. But if this happens, it will relieve the stress on the rest of the rig. The failure acts something like a fuse in an electrical circuit, a sacrifice that may perhaps save, in this case, the rest of the mast and maybe even the ship herself if it prevents a capsizing.
So, he concludes, sometimes the impulse to “strengthen” is misplaced. His bottom line: “Too much safety sometimes kills safety.”
In a similar vein, he warns against mixing traditional materials (wood, hemp, natural sailcloth) with metals. The former all yield and stretch, something metal does not do so well. “Metals resists…. [while] the rest of the system bows, bends and relaxes.” A too robust shroud might pull other parts of the rig out of this natural system.
Speaking of breaking points, here is Commander Salamander’s scorecard on the Navy’s new LCS ships:
- USS FREEDOM (LCS 1): Unavailable due to mechanical failures from JUL 16. San Diego.
- USS INDEPENDENCE (LCS 2): Available, PMC ASUW. NMC all other PMA.
- USS FORT WORTH (LCS 3): Unavailable due to mechanical failures from JAN 16. Limping to San Diego.
- USS CORONADO (LCS 4): Unavailable due to mechanical failures from AUG 16. Pearl Harbor.
- USS MILWAUKEE (LCS 5): Unavailable due to mechanical failures from DEC 15. Mayport.
- USS JACKSON (LCS 6): Unavailable due to post-shock test repairs. Mayport.
- USS DETROIT (LCS 7): Not commissioned until 22 OCT 16.
- USS MONTGOMERY (LCS 8): Not available due to mechanical failures from SEP 16.Limping to Mayport.
And as long as we’re keeping score, the many multibillion-dollar carrier USS Gerald R. Ford has got power generation troubles.
Photo credit: Wikimedia Commons