A new wrinkle in preventers

If the liquor locker is potentially the most lethal object aboard a boat number two has to be the boom. In uncontrolled flying jibes, I’ve seen battens break, sheets snap, shackles open and goosenecks rip right off the mast. If a crewmember is unlucky enough to get in the way of a swinging boom, the injury can be far worse than a bump on the head. I know people who have suffered boom-related concussions and permanently blurred vision. A neurosurgeon-sailor friend of mine, Garry Fischer, has identified 23 boom-related fatalities (19 of them in accidental jibes) plus another 21 nonfatal injuries involving booms and their rigging. He says the force of a swinging boom is so great even in light air that no helmet can be counted on to protect a head from damage.

The solution is the preventer. A line that stops the boom from swinging across the deck. It’s traditionally led from the boom forward to a turning block or other point on the leeward side, then reverses direction and runs aft along the lee deck to the cockpit so it can be adjusted without sending someone forward. Because a preventer takes a big load, it should end at a cockpit winch.

The problem is that most boats don’t seem to have enough winches to do the job. Such appeared to be the case aboard the Hylas 54 Capella IX when three able shipmates and I delivered it last November from Portland, Maine, to Tortola, British Virgin Islands. The ship has two winches on each side of the cockpit, but so many important lines — jib sheets for the double-headsail rig, plus four control lines for the roller-furling jibs and mainsail — that we usually were unable to free up a winch on the leeward side for the preventer.

It was Tom Upham who came up with the ingenious but simple solution: cross the preventers. Instead of running the line back on the leeward side, he led it to an unoccupied windward winch. The preventers crossed in the big turning block on the bow. Upham led the starboard preventer through this block from starboard to port and the port preventer through the same block from port to starboard. Each line was then led aft to the otherwise unoccupied windward cockpit winches.

With both preventers set up all the time, our two-man watches were able to manage controlled, safe jibes. It did take a while for us to get in the habit of reaching to the windward side every time we needed to tighten or ease the preventer, but this was a small price to pay for the security provided by Upham’s system. Our block’s sheave was big enough to accommodate both hefty preventer lines, but there’s no reason why two smaller blocks or a large bow cleat wouldn’t serve just as well.

John Rousmaniere is the author of The Annapolis Book of Seamanship (now in its third edition), Fastnet, Force 10, and other books, most recently, After the Storm (International Marine).

By Ocean Navigator