Darkness shut down on them suddenly as they thrashed her out to westward full and by, lurching with flooded decks over the charging seas. Their whitened tops broke over her, her canvas ran water, and every other minute she plunged into a comber with buried bows. The combers, growing rapidly higher, broke more angrily, and her progress changed into a series of jerks and plunges, which at times threatened to shake the spars out of her. Frank could see the black mainsail peak above him swinging madly up and down, and it seemed at times that half her length was out of the water, which was not improbably the case, for the foam upon her hove-up deck poured aft in cascades over the low coaming and splashed about their feet. By and by, for she was shallow-bodied like most centerboard craft, it began to gather in a pool which washed to and fro across the floorings in her lee bilge, and at a shout from Jake he started the pump. It needed no priming, for as soon as he unscrewed the covering plate the sea ran down, and there was now nothing to show what water it flung out, because half the lee deck was buried in a rush of gurgling foam and the combers' tops broke continuously over the bows. Still, the work roused and warmed him, and he toiled on, battered and almost blinded by flying brine, while he wondered how long the boat would stand the pressure of her largely reduced sail. He did not think they could tie another reef in, because it seemed certain that something must burst or break the moment a rope was started. Besides, even had it been possible, reefing was out of the question. Their harbor lay to weather, and a boat will not sail to windward in a vicious breeze unless she is driven at a speed which is greater than the resistance of the opposing seas. They thrashed her out for two anxious hours, since it appeared doubtful that she would come round and a failure to stay her would be perilous in the extreme, but at last Jake called to the boys. "We've got to do it somehow," he said. "Stand by your lee jibsheet and tail on to the mainsheet the moment you let it run. Hold on till I tell you. We'll wait for a smooth." A smooth, as it is termed by courtesy, is the interval that now and then follows the onslaught of several unusually heavy seas, and at length as the boat swung up with a little less water upon her deck Jake seemed satisfied. "Now! Helm's a-lee!" he shouted.