498 



HYDROGRAPHICAL SURVEYING [chap. xxi. 



to the moorings having tripped, and it may be generally best 

 to replace them at once, dropping the new beacons beforehand. 

 The scale can be readily checked at any convenient time and 

 place should there be reason to suppose that inaccuracy has 

 crept in. This should always be done after heavy weather, 

 or whenever it may be expected that the beacons have dragged 

 or ma}' be out of position from any cause. 



SECTION XVIII. 



ENTRIES IN THE DECK -BOOK RELATING TO BEACONS. 



(See also Sections III. and VI., para. .3, and also Section XIV.) 



In beacon work it is a good plan to reserve a space in the 

 deck-book where all information relating to every beacon is 

 there entered in a convenient tabular form, lists being prepared 

 for each ship. 



A specimen would include something as follows : 



Name and No. 



Date dropped, and by 



whom ; depth 

 Approximate position 



Distinguishing flag . . 



Bamboo 



Casks 



Visited 



Moorings 



Mack Beacon. 



Mack, No. 21. 



7 a.m., Monday, July 19th, 1911. 

 Depth, 23 fathoms. By Hearty. 



Near north end of Swarte Bank. Lat., 

 53° 30' 12" N.; Long., 1° 58' 46" E. 



See Fig. 116. 



Length, 35' 4". 



Black colour. 



1 p.m., July 19th, at S.E. stream (see 

 page 14 in deck-book). 



8 a.m., July 26th, at N.W. stream (see 

 page 15 in deck-book). 



6.30 p.m., July 31st, at S.E. stream (see 

 page 16 in deck-book). 



35 fathoms. Galvanised chain, ^. 

 One 120-lb. boat's anchor, eight 

 56-lb. Baillee sinkers. Heel-weights, 

 six 40-lb. galvanised iron ballast 

 with shackles. 



