A passage of Strabo[921] seems to show that--in the later times at any rate--they had a method of calculating the rate of a ship's sailing, though what the method was is wholly unknown to us.

It is probable that they early constructed charts and maps, which however they would keep secret through jealousy of their commercial rivals.
The Phoenicians for some centuries confined their navigation within the limits of the Mediterranean, the Propontis, and the Euxine, land-locked seas, which are tideless and far less rough than the open ocean.

But before the time of Solomon they had passed the Pillars of Hercules, and affronted the dangers of the Atlantic.[922] Their frail and small vessels, scarcely bigger than modern fishing-smacks, proceeded southwards along the West African coast, as far as the tract watered by the Gambia and Senegal, while northwards they coasted along Spain, braved the heavy seas of the Bay of Biscay, and passing Cape Finisterre, ventured across the mouth of the English Channel to the Cassiterides.
Similarly, from the West African shore, they boldly steered for the Fortunate Islands (the Canaries), visible from certain elevated points of the coast, though at 170 miles distance.

Whether they proceeded further, in the south to the Azores, Madeira, and the Cape de Verde Islands, in the north to the coast of Holland, and across the German Ocean to the Baltic, we regard as uncertain.

It is possible that from time to time some of the more adventurous of their traders may have reached thus far; but their regular, settled, and established navigation did not, we believe, extend beyond the Scilly Islands and coast of Cornwall to the north-west, and to the south-west Cape Non and the Canaries.
The commerce of the Phoenicians was carried on, to a large extent, by land, though principally by sea.