First, the boat cannot be left anchored in the open, as she will surely be lost or damaged in a gale. She must therefore be able 'to take the ground handsomely'; that is, she cannot have a deep keel, for her bottom must be broad and flat; and, secondly, she cannot have any weight of ballast in her, as it would fatally strain her when she stranded, and make her too heavy to draw out of the reach of the waves. Now, a boat with no keel and no ballast makes, as everyone knows, a bad sailor; in fact, she will only run dead before the wind like a duck's feather on the water: so a little keel of 3 in. or 4 in. is generally used, and the boat ballasted with sandbags filled on the beach, or stones, which are emptied or thrown overboard before landing again. This plan has the objections of being very laborious and making the boat very heavy to launch. If she ships two or three seas in the operation she becomes hopelessly submerged, and the advantages gained are very slight, as such a boat will scarcely sail closer to the wind than a broad reach--even then making considerable leeway and being very slow and uncertain in stays. It was to improve on this state of affairs on the beach of this description that is to be found at Shankill, in the county of Dublin, that the 'Water Wag' was evolved from a Norwegian _pram_, into which a boiler-plate was fitted for a centreboard as an experiment. This novel craft was called the 'Cemiostama.' She was built in the year 1878, and was a great success; she sailed like a witch, carried a large sail with ease without any ballast save the iron-plate, worked well to windward without making any leeway, spun round like a top when the tiller was put down, and when the boiler-plate was raised she ran in on the surf, floated in a few inches of water, and eventually sat on the strand on her flat bottom. The plate (which weighed nearly 1 cwt.) was then lifted out of her, and she became as light to haul up as an ordinary shore skiff. It was accordingly decided to build seven or eight centreboard double-ended 13-ft. punts with great beam (4 ft. 10 in.), full lines, and a flat floor. The 13 ft. was chosen as the best size that two persons could haul up without help, a larger boat being too heavy for two, and consequently liable to damage by being left in the surf while help was being obtained; and the round stern was to divide the surf when the forepart stranded, and prevent it jumping into the boat as it does in the case of a square stern.