4232 HYDROGRAPHIC MANUAL PaGE 326 



4232. Inspection Report of Leased Launch 



A complete inspection report, dated and signed, shall be forwarded to the Washing- 

 ton Office promptly at the beginning of every lease of a vessel or launch, and likewise on 

 the termination of the lease. The survey of the hull, machinery, and equipment shall 

 be made by a board of three officers, one of whom is an engineer officer. If three ward- 

 room officers are not available to make the survey, competent petty officers in the- 

 crew may act as members of the board to assist the senior member. 



4233. Desirable Type of Leased Launch 



The most satisfactory type of launch usually available lor lease for use in surveying 

 is the fishing or working type to be found in the locality where the survey is to be made. 

 Such launches are generally seaworthy, adaptable to hydrographic s-urveys, and can be 

 obtained at reasonable rates. They are invariably built to meet the conditions encount- 

 ered in the particular locality. One-man pilothouse control is preferable to two-man 

 control and the latter should never be used if the former is available. The smaller tj''pe 

 of fishing or working boat is usually constructed with a small cabin forward and a large 

 open cockpit over which is a removable awning. Yachts and pleasure craft are generally 

 unsatisfactory. 



Many such launches are powered by regular marine Diesel or gasoline engines, but 

 some are powered by automobile motors converted to rriarine use. The motor conver- 

 sion consists of the installation of a more powerful water pump, a special manifold, and 

 a reverse gear. Some mstallations use the automobile transmission for reverse gear, but 

 the marine clutch w^ith reverse gear is sturdier and better. Another type of power plant 

 encountered in some laimches is the old heavy-duty slow^-moving one-, two-, or three- 

 cylinder type. It is reliable but slow, and is usually direct-connected to the propeller. 

 A clutch and reverse are necessary in any launch to be used in hydrographic surv^eys. 



Speed is not essential in a launch to be used for handlead or wire sounding; reliable 

 motor performance at low speed is more important. On the contrary, if a portable 

 graphic recorder is to be used for sounding, or if the launch is to be used to transport a 

 topographic or signal-building party to and from the working ground, speed is of prime 

 importance. 



424. Small Boats 



Various types of small boats are used for sounding close to shore, surf, breakers, or 

 other dangers; for running to and from the working ground; for transportation of topo- 

 graphic, triangulation, and other working parties operating from a ship ; and for sounding 

 in shallow water when shallow-draft launches are not available. All of these boats can 

 be propelled by oars; most of them are designed so that outboard motors can be attached^ 

 although inboard engines are installed in some of them. 



4241. Whaleboat 



Whaleboats are very serviceable double-ended open boats of full beam and con- 

 siderable sheer, principally, used as lifeboats. They are generally 24 feet in length, with 

 a beam of 6 feet 10 inches, and they draw not to exceed 2% feet when fully loaded; they 

 weigh varying amounts, averaging about 2,000 pounds; they have a lifeboat capacity 

 of 23 men. They are equipped with air tanks forward and aft. Some whaleboats are 

 power-driven by inboard gasoline or Diesel engines. 



