108 THE EVOLUTION OF THE LIGHTSHIP. 



tinually demonstrated in general shipbuilding practice, and were finally forced 

 upon the lightship. Its first permanent use in the service came in a combination of an 

 iron frame and wooden planking for the hull. Of these composite vessels, a typical 

 illustration is that of the British Lightship Puffin, built in 1887 for the Commis- 

 sioner of Irish Lights. The vessel was designed for an exposed station on a stormy 

 part of the Irish coast, and special care was taken to make it both seaworthy and 

 habitable. The length over all was 10 1 feet 6 inches, length between perpendicu- 

 lars 93 feet 6 inches, moulded breadth 20 feet 9 inches, and the moulded depth 1 1 

 feet 10 inches. The iron frame carried an inside skin of 3-inch teak, fastened to 

 the frames by %-inch galvanized bolts and an outer skin of the same thickness 

 and material, which is fastened to the inner with %-inch copper clenched bolts. 

 Four bilge keels were fitted to reduce rolling. The moorings consisted of two 

 lengths of i%-inch cable, one of which was connected to a large mushroom an- 

 chor, while the other was fastened to a Troatman anchor lashed to the side, and 

 ready to be cut away should the first fail. The day signal consisted of two large 

 balls, each 6 feet in diameter, mounted one over the other. The light was carried 

 in a lantern house 8 feet in diameter, which encircled the mast and was capable of 

 being raised and lowered. The light revolved and was operated by clockwork in 

 the 'tween decks. 



A variation of composite construction was that wherein the iron or steel 

 plating of the hull was sheathed throughout with wood. By this means the interior 

 of the hull is somewhat protected from the effects of sudden changes and extreme 

 temperatures. The plating also is stiffened by the bulk of the wood against 

 sudden local shocks or blows, which might otherwise bilge the hull. An illustra- 

 tion of this sheathed constniction is given by U. S. Lightvessel No. 43, 

 built in 1 88 1, which has given many years' excellent service at South Pass, La. 

 The vessel is no feet 9 inches long, by 25 feet 8 inches beam, and 11 feet 6 inches 

 deep, with a gross tonnage of 191. It has a complete watertight iron hull, carried 

 to the main deck and entirely sheathed with 3 inches of yellow pine planking. 

 Aside from this distinctive construction, the vessel is an excellent type of the first- 

 class American lightship of the day, and while this sheathing serves its intended 

 purpose, the advantages do not generally warrant the increase in cost of labor and 

 material involved. 



A second variation of the composite construction is that in which the steel 

 framing of the hull is covered in part with wooden planking and in part with steel 

 plating. The U. S. Lightvessels Nos. 68, 69, 70, and 71 built in 1897 for stations 

 on the Atlantic and Pacific Coasts were of this type. They are vessels of the first 

 class in dimensions and characteristics. The framing, stem, stern, and keel, a bilge 

 strake, and the topside plating were of steel. The entire bottom, from the line of 

 the main deck down, was planked with white oak and sheathed with composi- 

 tion. All have occupied stations of the first importance, and are still in constant 

 use despite extended service on the Diamond Shoal and other equally exposed 

 stations. 



