ENGINEMAN 1 & C
The Navy preferred containment equip-
ment/procedures are piston film chemicals and
solid, floating booms.
Piston Film Chemicals.Piston film
chemicals have high surface activity and spread
rapidly over the water surface. The spreading
force of the chemical is sufficient to overcome the
spreading forces of the slick. These chemicals push
the oil layer back until it reaches a limiting slick
thickness, which the piston film cannot exceed.
The oil may be moved ahead of the spreading film
toward a collecting or containment device as
shown in figure 8-2A, or the piston film may be
quickly spread around the periphery of the spill
as is shown in figure 8-2B. This technique simply
slows down the spreading rate.
Containment Booms.Containment booms
are solid (floating barrier) booms. They are solid,
continuous obstructions to the spread or migra-
tion of oil spills. Because they are the most
effective containment device, they are preferred
for use with Navy related spills.
1. Booms are available in various sizes (in
50-foot lengths) which are joined to form a con-
tinuous barrier to the oil. Their freeboard must
be sufficiently high to prevent the oil from being
washed over the boom, and the skirt long enough
to prevent oil from being swept under it. Booms
are purchased in several height/depth sizes to meet
their use requirements under various wind and sea
conditions.
2. Booms may be used in either a dynamic
(towed) mode or in fixed position. Figure 8-3.I
shows a boom being towed in a vee configura-
tion in conjunction with a skimming device. The
boom directs the oil to the skimming device where
it is collected.
3. Booms are also being used to prevent oil
from going under the pier and to direct the oil
to the skimmer (figure 8-3.II). The slick is
moved to the skimmer under the influence of wind
and current, or it could be pushed toward the
skimmer by hose spray, air jet, or piston film, if
necessary.
4. Booms may be anchored in a position that
will entrap the oil but leave a channel open for
navigation if necessary (figure 8-3.III). The angle
at which the boom must be set is important in
order to avoid loss of collected oil due to entrap-
ment in the current or from being carried under
boom skirts.
5. Figure 8-3 .IV depicts typical use of a boom
stretched across a stream. This alinement is feasi-
ble in small streams, mild currents, or tidal
Figure 8-2.Use of Piston Film Chemicals.
8-6