24 GENERAL NAVIGATION. 



3. The heaviest and thickest oils are most effectual. Eefinecl kero- 

 sene is of little use ; crude petroleum is serviceable when nothing else 

 is obtainable; but all animal and vegetable oils, such as waste oil 

 from the engines, have great effect. 



4. A small quantity of oil suffices, if applied in such a manner as 

 to spread to Avindward. 



5. It is useful in a ship or boat, either when running, or lying-to, 

 or in wearing. 



6. No experiences are related of its use when hoisting a boat at sea 

 or in a seawaj^, but it is highly probable that much time would be 

 saved and injury to the boat avoided by its use on such occasions. 



7. In cold water the oil, being thickened by the lower temperature 

 and not being able to spread freely, will have its effect much re- 

 duced. This will vary with the description of oil used. 



8. For a ship at sea the best method of application appears to be to 

 hang over the side, in such a manner as to be in the water, small 

 canvas bags, capable of holding from 1 to 2 gallons of oil, the bags 

 being pricked with a sail needle to facilitate leakage of the oil. 



The positions of these bags should vary with the circumstances. 

 "Running before the wind, they should be hung on either bow — e. g., 

 from the cathead — and allowed to tow in the water. 



With the wind on the quarter the effect seems to be less than in 

 any other position, as the oil goes astern while the waves come up on 

 the quarter. 



Lying-to, the weather bow, and another position farther aft, seem 

 the best places from which to hang the bags, using sufficient line to 

 permit them to draw to windward while the ship drifts. 



9. Crossing a bar with a flood tide, to pour oil overboard and allow 

 it to float in ahead of the boat, which would follow with a bag tow- 

 ing astern, would appear to be the best plan. As before remarked, 

 under these circumstances the effect can not be so much trusted. 



On a bar, with the ebb tide running, it w^oulcl seem to be useless to 

 try oil for the purpose of entering. 



10. For boarding a wreck, it is recommended to pour oil overboard 

 to windward of her before going alongside. The effect in this case 

 must greatly depend upon the set of the current and the circum- 

 stances of the depth of water. 



11. For a boat riding in bad weather from a sea anchor, it is recom- 

 mended to fasten the bag to an endless line rove through a block on 

 the sea anchor, by which means the oil can be diffused well ahead of 

 the boat and the bag readily hauled on board for refilling, if necessary. 



