280 YACHT EQUIPMENT 



lengths of wire, with no brazed joins ; the latter are 

 apt to give way under a severe tension, and to catch 

 and strand when running through a fair lead. It is 

 possible that so stiff a rope would kink if used for 

 bottom work. 



B.— Shallow Water. 



The hints already given relate to the most difficult 

 and troublesome part of all oceanographic work, that 

 which involves the most power, time, weight, storage- 

 space, skill, care, and expense. If deep-sea work is the 

 most ambitious, it is also the most interesting ; if it is 

 the most difficult, it is also the most needed, and the 

 most productive of striking results. 



On the other hand, excellent and valuable work can 

 be done at small depths in almost any part of the 

 world. Even in home waters little has been done 

 systematically outside the ioo-fathom line ; beyond 

 home waters (except in one or two favourite areas) 

 anyone with a rowing-boat and a little apparatus can 

 add materially to knowledge. 



i. Dredging and Trawling. 



In shallow water, down to (say) 200 fathoms near 

 land, it must be remembered that if the net catch on 

 rocky bottom, a breeze acting on the freeboard of a 

 large yacht or steamer will impose a very great strain 

 on the rope ; a trawl full of stones or mud is also a 

 menacing possibility. For such work a ij-inch or ij- 

 inch rope, with a breaking-strain of 4 to 8 tons, is 

 desirable ; the lifting power of the deck engine can be 

 somewhat reduced, but an accumulator or some 

 similar protection is certainly required, and a recording 

 sheave indispensable. With this gear a yacht can 



