Maury’s Improvements on the Old Route to the Colonies.
In more ways than one we owed America thanks for shortening the passage to Australia—and not least to the sailing directions advocated by her great wind expert Maury. In the days before the gold discovery vessels followed the route laid down by the Admiralty; they kept as much to the eastward as possible on their way south in order to avoid the dreaded Cape San Roque and its leeward currents; they rounded the Cape of Good Hope close to, indeed often touched there, then kept well to the north of the forties running their easting down. Then a 120-day passage was considered very good going, and when Captain Godfrey, of the Constance and Statesman, went out in 77 days by sailing on a Great Circle track, his performance created a huge sensation in shipping circles.
Maury did not actually advocate running the easting down on a Great Circle; but what he did was first to dispel the bugbear of Cape San Roque, which, however much it may have worried the leewardly craft of the old days, could have but little effect upon the fast weatherly ships of the fifties. He next showed the advantages of sailing on a Great Circle from San Roque so as to get into the high latitudes as soon as possible. He was dead against bracing sharp up against the S.E. trades.
“Australian-bound vessels are advised,” he writes, “after crossing the equator near the meridian of 30° W., say between 25° and 32°, as the case may be, to run down through the S.E. trades, with topmast studding sails set, if they have sea room, aiming to cross 25° or 30° S., as the winds will allow, which will be generally somewhere about 28° or 30° W., and soon, shaping their course, after they get the winds steadily from the westward, more and more to the eastward, until they cross the meridian of 20° E., in about lat. 45°, reaching 55° S., if at all, in about 40° E. Thence the best course—if ice, etc., will allow—is onward still to the southward of east, not caring to get to the northward again of your greatest southern latitude, before reaching 90° E. The highest latitude should be reached between the meridians of 50° and 80° E. The course then is north of east, gradually hauling up more and more to the north as you approach Van Dieman’s Land. The highest degree of south latitude, which it may be prudent to touch, depending mainly on the season of the year and the winds, the state of the ship, and the well-being of the passengers and crew.”
This last sentence was a very important qualification of the Great Circle route, and it is evident that Maury quite realised that only very powerful, well found ships could adventure far into the fifties without being made to pay severely for their temerity.