The date was October 26th. The lives of Stimpson, Bylander, and Leonard were about to converge with several dozen others off the New England coast.
BILLY, like Leonard, has undoubtedly heard the forecast, but he's even less inclined to do anything about it than Leonard is. The lead time for an accurate forecast is only two or three days, and it takes twice that long for a sword boat to make port. Weather reports are vitally important to the fishing, but not so much for heading home; when the end of the trip comes, captains generally just haul their gear and go. Because errors compound, the longer the trip, the more careful the captain has to be when he sets his initial heading for home. An error of just one degree puts a boat thirty miles off-course by the time she gets back to Gloucester; a captain could add a day to each trip with a month of such errors. When Billy Tyne starts for home, a bearing of 260 degrees would run him straight into Cape Ann, but it would also shave too close to Sable Island, which presents a ghastly hazard to shipping. ("I try to avoid it by at least forty or fifty miles," says Charlie Reed.) The channel between Sable and Nova Scotia is blessed with a good, cold countercurrent that starts in Labrador and hugs the coast all the way down to Hatteras, but for some reason Billy decides not to take it. He decides to cross the Tail around 44 degrees north—his "waypoint"—and then, once clear of Sable, shoot a course almost due west for Gloucester.
Fishing boats use a global positioning system for bluewater navigation. GPS, as it's called, fixes a position relative to military satellites circling the earth and then converts it to longitude and latitude. It's accurate to within fifteen feet. The Department of Defense intentionally distorts the signals because they're worried about the misuse of such precise information, but the standards of accuracy on a sword boat are loose enough so that it doesn't matter. Fishermen generally use GPS to back up a loran system, which works by measuring the time it takes for two separate low-frequency radio signals to reach the vessel from broadcasting stations on shore. Charts are printed with numbered lines radiating out from the signal sources, and a loran reading identifies which lines correspond to the vessel's position.
Even with two electronic systems, though, mistakes happen—iron-bearing landmass, electrical interference, all kinds of things skew the output. Furthermore, the plotter gives you a pure direction, as if you could slice right through the curvature of the earth, but boats must follow an arc from point to point—the "Great Circle" route. The Great Circle route requires a correction of about eleven degrees north between Gloucester and the Flemish Cap. On the night of October 24th, Billy Tyne punches in the loran coordinates for his waypoint on the Tail of the Banks and reads a bearing of 250 degrees on his video plotter. On a Great Circle route, the compass heading and the actual heading are identical at the start of a trip, gradually diverge until the halfway point, and then converge again as the boat nears its destination.
Having determined his Great Circle route and plugged the heading into the autopilot, Tyne then goes over to the chart drawer and pulls out a ten-dollar nautical chart called INT 109. He lines up a course of 250 degrees to his waypoint on the Tail and then walks his way down the map with a set of hinged parallel rules. He rechecks the bearing at the compass rose at the bottom and then adjusts by twenty degrees for the local magnetic variation. (The earth's magnetic field doesn't line up exactly with the axis of the earth; in fact it doesn't even come close.) That should bring him to his waypoint on the Tail in about three days. From there he'll come up fourteen degrees and take another Great Circle route into Gloucester.