Embarrassments also of a minor yet serious character had to be encountered. Our vessels, unlike those of England, were designed exclusively for war, and long confinement impaired the efficiency of the men. The government supplies of eatables needed to be eked out from New Orleans huckster boats and European merchant ships. Water could not be obtained readily from a hostile shore. At the Antigua River, in July, 1846, the boats going up with casks were fired upon, and such affairs had to be expected. Vessels were despatched long distances occasionally to obtain fresh provisions, but even then scurvy of a most serious nature broke out in the summer of 1846, disabling some of the largest and most efficient ships for several months. The _Raritan_ had more than 200 cases. Nearly all on the _Potomac_ suffered. The _Falmouth_ had to go as far north as Boston to throw it off. Swampy shores and kelp rotting under the torrid sun produced myriads of poisonous as well as otherwise annoying insects. During a brief stay in the river off Tampico nearly all the officers and men contracted ague, and the yellow fever scourged a number of the vessels. More than two thirds of those on the _Saratoga_ had the latter disease. In August, 1847, the _Mississippi_ left her station with some 200 men suffering from it.[30.10] Being strangers and enemies, the Americans labored under peculiar disadvantages. The people gladly assisted blockade runners in every possible way. Spanish captains in particular, having friends on shore and pilots thoroughly familiar with the coast, could not be prevented from reaching harbor at night or in thick weather by way of the shoals. Sometimes it looked, for one or another of these many reasons, as if our officers were careless or incompetent. Army observers, not well informed regarding the conditions, felt disposed now and then to pronounce the blockade a humbug, and naturally some foreigners did so. This opinion had neither truth nor probability in its favor. But naturally, in view of all the circumstances, it proved more satisfactory to occupy the ports, and open them to commerce on the basis of a reasonable contributory tariff.[30.11] [OFFENSIVE NAVAL OPERATIONS]