Page vi contents 



Page 



25. Control buoys 109 



251. Sextant location of a single buoy. 252. Directions and sun azimuths in locating 

 a single buoy. 253. Other methods of locating a single buoy. 254. Planning buoy 

 control. 255. Buoy-control schemes for location by sextant. 256. Buoy-control 

 schemes for location by taut-wire traverse. 257. Buoy-control schemes for location 

 by other methods. 258. Statistics of buoy-controlled surveys. 



26. R.A.R. stations 147 



261. R.A.R. shore stations. 262. Ship stations. 



27. Signal building 151 



271. General statement. 272. Tall signals. 273. Steel towers. 274. Water signals. 

 275. Signal cloth. 276. Whitewash. » 



28. Survey buoys 162 



281. Buoys in general. 282. Buoy construction. 283. Anchoring gear. 284. Sono- 

 radio buoy. 285. Handling buoys from the ship. 286. Record of buoy positions. 



Chapter 3.— HYDROGRAPHY 



31. General statement 191 



311. Depth measurements. 312. Project limits. 313. Project and survey junctions. 

 314. Systems of sounding lines. 315. Spacing sounding lines. 



32. The boat sheet 203 



321. Definition and purpose. 322. Construction of boat sheet. 323. Preparation of 

 boat sheet. 324. Use of boat sheet during survey. 325. Details on completed boat 

 sheet. 326. Shipment of boat sheet. 



33. Horizontal control of hydrography 211 



331. Positions. 332. Methods of control. 333. Sextant three-point fixes. 

 334. Large-scale surveys. 335. Positions by estimation. 336. Bearings and distances. 

 337. Dead reckoning. 338. Astronomic sights. 



34. Hydrographic operations 250 



341. Personnel and their duties. 342. The operation of sounding. 343. Frequency 

 of soundings (sounding interval). 344. The operation of position fixing. 345. Mis- 

 cellaneous operations. 346. Handling the survey vessel while sounding. 



35. Adequacy of hydrographic survey 267 



351. A basic survey. 352. Previously known dangers and shoal soundings. 

 353. Depth curves. 354. Adequacy of the general system of lines. 355. Development. 

 356. Ranges, bearings, and sailing lines. 357. Crosslines. 



36. Dangers and shoals 275 



361. Danger of surveying shoals. 362. Sources of evidence. 363. Bare rocks and 

 rocks awash. 364. Sunken rocks and breakers. 365. Wrecks and obstructions. 

 366. Examination of shoals. 367. Development of large shoal areas. 368. Develop- 

 ment of an offshore shoal. 



37. Large-scale offshore surveys 286 



371. Derivation of formulas. 372. Preparing circle sheets. 373. Preliminary layout. 

 374. General case. 375. Modifications of the general case. 376. Various methods 

 of use. 



38. Contemporary operations 296 



381, Shoreline by hydrographer. 382. Form lines from the ship. 383. Aids to navi- 

 gation. 384. Character of the bottom. 385. Descriptive report and coast pilot notes. 



39. Special types of surveys 307 



391. Wire-drag surveys. 392. Survey in advance of control. 393. Isolated harbor 

 survey. 394. Reconnaissance survey. 



Chapter 4.— EQUIPMENT AND INSTRUMENTS 



4 1 . Survey ships and auxiliary vessels 311 



411. General description of a survey ship. 412. Ship Explorer. 413. Motor 

 vessel E. Lester Jones. 



