USE OP OIL ON BREAKING WAVES 97
"The following may serve for the guidance of seamen, whose atten-
tion is called to the fact that a veiy small quantity of oil, skilfully
applied, may prevent much damage, both to ships (especially the
smaller classes) and to boats, by modifying the action of breaking seas.
"The principal facts as to the use of oil are as follows:—
"1. On free waves, i.e , waves in deep water, the effect is greatest.
"2. In a surf, or waves breaking on a bar, where a mass of liquid is in
actual motion in shallow water, the effect of the oil is uncertain,
as nothing can prevent the larger waves from breaking under
such circumstances; but even here it is of some service.
**3. The heaviest and thickest oils are most effectual. Refined
kerosene 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.
"L A small quantity of oil suffices, if applied in such a manner as to
spread to windward
"5. It is useful in a ship or boat, both when running or lying to, or
in wearing.
"6. No experiences are related of its use when hoisting a boat up in
a seaway at sea, but it is highly probable that much time and
injury to the boat would be savxjd by its application on such
occasions.
"At anchor, when the sea is sufficient to render it difficult to hoiat
up or to launch boats, oil bags from forward or from the
swinging booms have been found to render the sea alongside
comparatively smooth.
"7. In cold water, the oil, being thickened by the lower temperature,
and not being able to spread freely, will have its effect much
reduced. This will vary with the description of oil used.
U8. The best method of application in a ship at sea appears to be—
hanging 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,
such bags being pricked with a sail needle to facilitate leakage of
the oil.
"The position of these bags should vary with the circumstances,
Running before the wind they should be hung on either bow—
e.g., ffom the cathead, and allowed to tow in the water,
"With the wind on the quarter the effect seems to be lesa than in any