Page 317 equipment and instruments 4113 



supply, but for emergency purposes it should be capable of being operated at a reduced 

 power of 50 watts from a 12-volt heavy-duty storage battery. The intemiediate- 

 frequency receiver should be battery operated, or a combination receiver operated 

 from either a battery or alternating current. 



The second code transmitter should be a crystal-controlled high-frequency trans- 

 mitter with a 150-watt rating. Two frequency-controlling crystals, one of 4135 kc 

 and another of 4160 kc, should be provided in the transmitter. It should be capable 

 of opeiating on the harmonics of both crystals, up to and including the third harmonic. 

 Power to operate this transmitter should be from the ship's power supply. The high- 

 frequency receiver should have an approximate frequency range from 0.5 to 30 mega- 

 cycles. It may be either a-c or d-c operated, although the former is usually preferred. 



In addition to the regular equipment, there should be an automatic SOS alann 

 and a ship-to-shore telephone. The radio room, or one adjacent to it, should have 

 sufficient space for workbenches and stowage of tools, spare parts, and other equipment. 



The radio technicians, in addition to their routine radio duties, repair and keep in 

 good order the echo-sounding instruments, radio direction finder, chronograph, etc.; 

 build, repair, and service sono-radio buoys and R.A.R. shore stations; build and repair 

 radio sets and attend to their installation in launches and camps; and design and 

 develop, for use in survey operations, new instrumental equipment which involves the 

 use of radio or electricity, and improve existing equipment. 



4113. Ship Drafting Room 



The importance of the drafting room on a survey ship is second only to the pilot- 

 house and bridge, and because of the considerable amount and kind of work which is 

 done in it, it is essential that it be ample in size and well lighted. ' 



The drafting room should be large enough to contain several drafting tables, a desk 

 or two, a file case, and a rack for boat and smooth sheets. The drafting tables generally 

 consist of table tops mounted on a base in which there are numerous large and medium- 

 sized drawers in which to stow flat the smooth sheets, topographic sheets, drafting paper,, 

 charts, and maps; and for record books and small drafting instruments and equipment. 

 The tops of the draftmg tables are specially constructed of laminated selected white 

 pine, 1}2 inches thick, stifl'encd on the underside, with kerfs to prevent warping. 



Where space permits, one large drafting table should be about 8 feet long for use 

 in constructing large boat and smooth sheets and circle sheets (see 3741c). 



There should be bookshelves for the various manuals, tables, and reference books; 

 and a locker conveniently accessible in which confidential data may be locked. 



The importance of the illumination cannot be overemphasized. There should be 

 as many windows to admit natural light as practicable and a system of indirect light- 

 ing or fluorescent lamps to eliminate shadows and to give near-daylight conditions at 

 night. The latter is particularly important as a large amount of night work is necessary 

 in connection with man}" of the hydrographic and survey operations. Improper light- 

 ing strains the eyes, especially at night after they have been used all day. With the 

 illuminating equipment now available an improperly lighted drafting room is inexcusable, 

 and the use of lights of low wattage and the operation of the ship's generator at a low 

 voltage are considered false economy. They lead to expensive errors and inaccurate 

 work. 



