The Year of the Boat

Author:Lawrence W. Cheek
Language: eng
Format: epub
Publisher: Sasquatch Books
Published: 2011-07-20T16:00:00+00:00

CHAPTER 10

THE ZEN OF SCREWING UP

UNLESS YOU’VE DESIGNED, built, repaired, or bought a sailboat, you’ve never devoted a second’s thought to what one looks like below its waterline. Frankly, it’s not pretty. With rare exceptions, a full-Monty view of a full-keel sailboat out of water ruins the impression of grace that it had exuded afloat. It now looks bloated, bathtubby, heavy in the hips. But sailboat design works exactly like natural selection in nature. Over millennia, sailboats have evolved the shapes and appendages they need to survive and move most efficiently, nothing more or less. This is a prime reason behind our fascination with them: no other human-made device has so closely paralleled Nature’s own process of evolution.

Until I started studying sailboats and pondering plans, it had never occurred to me that a sailing vessel needs anything other than a sail and a rudder to tack its way around the world. But of course it does. Most of the time a sailboat is not simply running downwind, but is moving at some angle to the breeze—perpendicular or even upwind. If there weren’t some force acting underwater to resist that topside wind, the boat would be a chunk of driftwood sporting a skinny branch and a big leaf, always getting itself blown sideways instead of moving forward. Worse, whenever the wind puffed vigorously enough, the chunk would roll and topple over. To avert these unhappy events, large sailboats have deep keels—lead-weighted fins that extend several feet below the centerline of the hull. The water fiercely resists the slab side of that fin from shoving sideways through it, but offers little resistance to the slim leading edge. Thus the thrust that the wind puts into the sail gets translated into forward motion.

Until some 2,000 years ago, sails were square and sailboats mostly traveled downwind. When the triangular sail appeared, probably as an Arab invention, upwind sailing finally became possible, although European ships stubbornly continued to use oars for windward thrust for another 1,500 years. Viking ships were as sleek as giant kayaks; they didn’t need keels because the square sail was only hoisted when the wind blew in the direction the captain wanted to go. The ships of the European Renaissance, finally, adopted combinations of sails that allowed better windward mobility, and they necessarily developed deep, heavy keels.

But by the time of North American colonization, more evolutionary improvements needed to happen. Deep drafts caused trouble for working boats that had to navigate the shallow bays and estuaries of North America’s East Coast. Keels were obviously impractical as well for small sailboats (like my Zephyr) intended to be launched from a beach. The solution was some kind of retractable keel, either in the form of a centerboard (which pivots down) or a daggerboard (thrusts down). Like many innovations in sailboat design, this idea had a foggy and disjointed provenance. Some ancient Chinese small boats had used centerboard-like devices, as had a form of native South American sailing raft, the jangada. Still, a British naval lieutenant named John Schank claimed to have invented it while stationed in Boston in 1771.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.