FOULING OF SHIPS' BOTTOMS 



195 



numbers accurately to determine their relations as life communities. When, however, 

 the bottom of a ship is raised out of water, these communities, in their entirety and 

 uninjured, can be seen and qualitative and quantitative studies can be made. The 

 effect of depth in producing distinct zonations may be studied easily on ships' 

 bottoms, and these special groups of organisms can be studied thus in detail. 



The study of this problem also presents data for the solution of the problem of 

 geographical distribution. It has long been a debated question whether a given 

 species of barnacle or other organism attached to the bottom of a boat can survive 

 transportation to another port and continue to live and reproduce its kind. Whether 

 one can explain the mundane distribution of some species of organisms in this manner 

 never has been determined. 



Data have been obtained that have a specific bearing on the question of the 

 effect of pollution in our harbors and the ability of some types of organisms to sur- 

 vive. The rate of growth of different kinds of organisms can be studied from these 

 data, as can also the problem of seasonal variation in their abundance. The effects 

 of various poison paints, of sunlight, temperature, salinity, and of tidal currents are 

 all of interest in a biological study of this problem and have been considered wherever 

 possible during this investigation. 



The author was assisted in the examination of ships by F. A. Varrelman and in 

 some of the experimental studies by R. H. Luce. To the authorities of the Bureau 

 of Fisheries and of the United States Navy, as well, and especially to Capt. Henry 

 Williams, he is very grateful for many courtesies and continued interest in this 

 work. For the use of laboratory facilities during the course of this investigation he is 

 grateful to the directors of the zoological laboratory of the Johns Hopkins University, 

 of the United States Fisheries laboratories at Woods Hole, Mass., and Beaufort, N. C, 

 and of the biological laboratory of the Western Reserve University at Cleveland, Ohio. 



HISTORY OF THE PROBLEM 



The problem of fouling growths on the hulls of ships naturally is not a new one, 

 for fouling has occurred ever since ships first were used. We seem to have no record 

 regarding the earliest methods of prevention, but Atheneus (200 B. C), quoted by 

 Ewbank, informs us that ''the ships of Archimedes were fastened everywhere with 

 copper bolts and the entire bottom [of wood] was sheathed with lead." Alberti 

 [in his work on architecture, published in the fifteenth century] tells us that a ship 

 called "Trajans ship" was salvaged from Lake Riccia, where it had been submerged 

 for more than 1,300 years, and that "over all, there was lead, fastened on with 

 copper nails." 



Young (1867) records the fact that a Roman ship, sunk in the Lake of Nemi, 

 was found to have been coated with bitumen, over which sheets of lead had been nailed. 

 The seams of the vessel were caulked with "tow and pitch," the hull being made of 

 larch wood. In the reign of Henry VIII (1510 to 1547) vessels were covered with a 

 coating of loose animal hair, attached over pitch, over which a sheathing board about 

 an inch in thickness was fastened to keep the hair in its place. In the reign of Charles 

 II (1660 to 1685) " the Phoenix and 20 other of His Majesty 's ships were sheathed with 

 lead and fastened with copper nails." That these methods were not satisfactory 



