brainlest???
Step-by-step explanation:
Sailing ships were the backbone of ancient commerce and travel. They carried freight, passengers, news. How fast could they move from port to port? The question, an old one, has been dealt with numbers of times. The handbooks and the economic histories have taken it up in detail and even the general histories have given it a passing word.
Despite all this attention, the subject requires a complete re-examination.1 One reason is that the scholars who have concerned themselves with it have committed more than their fair share of blunders.2 Another is that nobody has ever assembled all the available evidence.3 Passages from ancient authors cited by earlier  p137 writers have been overlooked by those who came later while some excellent evidence offered in an ancient work entitled, of all things, "The Ship" was not used until 1941.4 The most important reason, however, is a far more basic one, namely, the approach to the problem.
The technique used up to now has been to provide a list of various miscellaneous voyages and from it to deduce what the "average speed" of ancient ships was,5 or let the reader deduce it.6 The lists (though not complete) are uniform; the "average speeds" are worthless. How could they be otherwise? They ignore the fundamental fact that the speed of a sailing ship depends first and foremost on the direction of the wind. Against the wind, 100 miles can take as long as or longer than 200 miles with the wind. Columbus flew to America with the trade winds at his heels. When he met contrary winds while working north along the coast of South America he was lucky if he logged one mile forward an hour. To combine the two voyages to strike an average speed will produce nothing worthwhile beyond some practice in arithmetic. In the study of the speed of ancient voyages, the very first step must be to classify them according to the winds encountered en route.
A sailing vessel travels best under a wind that is blowing from some point abaft the beam. The ship can then move at its fastest directly toward its destination. Such a wind, whether blowing directly over the stern or over the quarters (i.e., from a point on either side of the stern) is a favorable wind. Unfavorable or "foul" winds are those that blow from some point ahead. These force a vessel to tack, i.e., sail at an 80 degree angle to the wind, a procedure  p138 that is uncomfortable, wearisome, and slow. The vessel heels heavily, the decks are forever wet with spray, and the sails are constantly being reset. When the destination lies 80 degrees to the right or left of the direction from which the wind is blowing, a vessel can head directly for it. More often the destination lies either nearer than 80 degrees or right in the eye of the wind and then the ship must tack back and forth in zigzag fashion. This is the most time-consuming course of all since it forces the vessel actually to cover far more distance than a straight line to its goal would measure.7
To determine the rate of speed of the voyages recorded in ancient literature, we must first distinguish between those made under fair and those under foul winds. Fortunately, in many cases we are specifically told what the wind conditions during the voyage were. Where we are not told we can often, by using modern hydrographic information concerning prevailing winds, make a very good guess.8
Voyages Made Under Favorable Winds
Pliny the Elder, in a much-quoted passage (19.3‑4), mentions a pair of record voyages and a number of others that he obviously intends as examples of fast runs. All must have been made, of course, before favorable winds. The voyages are as follows:9
