654 OIL ON TEOUBL.ED WATERS. 



IS very conclusive, and no vessel should neglect its us© in emergencies, 

 such as when heavy seas threaten to break on board. Once tried, its 

 value will never be disputed, and those who are sceptical are urged to give 

 it a fair trial. The experiment can be very easily made, and at small 

 expense, while the results, as reported, have been almost invariably suc- 

 cessful. All that seems to be necessary is to rig up any sort of simple 

 apparatus which will ensure a small but steady flow of Oil. 



"When Oil is poured on a rough sea, it quickly spreads around and to 

 windward, preventing the waves breaking. Lord Rayleigh, in a lecture 

 before the Eoyal Institution, 1890, stated that its action may be compared 

 to an inextensible membrane, floating on the surface of the water, and 

 hampering its motion, thus rendering the formation of waves difificult. 

 Of course, in a surf, or on breaking bars or shoals, its action cannot 

 entirely overcome the momentum of the seas, but it exercises a con- 

 siderable calming effect. Ships' boats should always be provided with a 

 supply of suitable Oil, only a small quantity being necessary, if proper'/ 

 applied, and it might, at times, be very useful in hoisting or lower'ag 

 boats in a sea. With the wind on the quarter, the effect seems to be .ess 

 than in other position, as the Oil goes astern while the waves como up 

 on the quarter. 



With regard to the best form of Oil for this purpose, it is found that 

 animal and vegetable Oils are most suitable, such as sperm, turpentine, 

 rape, linseed, cotton-seed, castor, almond, and olive. Minei'al Oils exert 

 little influence upon rough seas, though crude petroleum has given 

 favourable results ; when refined it is not so good. Thick and heavy Oils 

 are the best ; but some, such as cocoa-nut oil and some kinds of fish-oil, 

 congeal in cold weather, and are then useless, but they may advan- 

 tageously be mixed with mineral oil. 



From actual use, it has been found that the tendency of petroleum to 

 spread itself over the water is only about one-half that of olive oil, 

 one-third that of linseed oil, one-fourth that of sperm oil, and one-fifth 

 that of soap-suds. Soap, dissolved in fresh water, seems the best agent 

 for preventing the groiuth of waves, both on account of its superior 

 spreading power and the reduction of the surface-tension that it brings 

 about ; but it has the drawback of mixing with the water, instead of 

 forming a coating on the surface. Its action in preventing the breaking 

 of heavy seas is also doubtful. Oil of turpentine is the best for spreading, 

 and reducing the tendency of the wind to form waves and increase their 

 size. Some consider porpoise oil very effective, and one observer states 

 that from 1 to 3 gallons, used in a bag of oakum, will run a vessel through 

 a prolonged gale. 



Probably the best way to use Oil, is by filling the forward closet-bowls 

 with oakum and Oil, or using a can with a drip-tap, which thus allows 

 it to run slowly out through the waste-pipes. Another simple and good 

 method of distributing it, is by canvas bags about one foot long, filled 

 with oakum and Oil, and pierced with holes by a coarse sail-needle, and 

 held by a lanyard. Another method is to use a small barrel, with a tap 

 and small hose leading down to the water ; this can be slung in any 

 desired position. 



