Other nations in the seventeenth century were not slow to follow the same course; and two circumstances contributed to make that course easy. One was the great length of coast line on both the Atlantic and Pacific slopes over which a surveillance had to be exercised, making it difficult to catch the interlopers. The other was the venal connivance of the governors of the ports, who often tolerated and even encouraged the traffic on the plea that the colonists demanded it.[36] The subterfuges adopted by the interlopers were very simple. When a vessel wished to enter a Spanish port to trade, the captain, pretending that provisions had run low, or that the ship suffered from a leak or a broken mast, sent a polite note to the governor accompanied by a considerable gift. He generally obtained permission to enter, unload, and put the ship into a seaworthy condition. All the formalities were minutely observed. The unloaded goods were shut up in a storehouse, and the doors sealed. But there was always found another door unsealed, and by this they abstracted the goods during the night, and substituted coin or bars of gold and silver. When the vessel was repaired to the captain's satisfaction, it was reloaded and sailed away. There was also, especially on the shores of the Caribbean Sea, a less elaborate commerce called "sloop-trade," for it was usually managed by sloops which hovered near some secluded spot on the coast, often at the mouth of a river, and informed the inhabitants of their presence in the neighbourhood by firing a shot from a cannon. Sometimes a large ship filled with merchandise was stationed in a bay close at hand, and by means of these smaller craft made its trade with the colonists. The latter, generally in disguise, came off in canoes by night. The interlopers, however, were always on guard against such dangerous visitors, and never admitted more than a few at a time; for when the Spaniards found themselves stronger than the crew, and a favourable opportunity presented itself, they rarely failed to attempt the vessel.