Method and apparatus for controlling water surface activity

The surface activity (more especially waves) of a body of water is reduced by providing a succession of booms at least partially surrounding said body of water (preferably moored so as to be substantially stationary) so that the surface of said body of water (preferably a major proportion or all of said surface) is substantially isolated by the presence of said booms in relation to the surface of water peripherally external with respect to said booms and the surface activity of said body of water is reduced by the distribution on the surface of said body of water as thus isolated by said succession of booms of a material at a cryothermal temperature at or below the freezing point of the water that preferably is in the form of a cascade of ice particles. Preferably surfaces of succession booms that face the so isolated body of water present material at a cryothermal temperature that is in contact with the water surface. Petroleum constituting an oil spill may be cleaned up and recovered while the surface of said body of water is isolated as aforesaid by said booms and preferably also is calmed by said distribution thereon of said material at a cryothermal temperature and preferably also by movement toward said spill of boom means presenting a material at said cryothermal temperature that is in contact with the water surface and that faces said oil spill.

This invention is concerned with reducing the surface activity of a body of 
water. It is concerned especially with reducing wave activity although it 
also contemplates the reduction of current activity either per se or as 
combined with wave activity. 
There are a number of circumstances under which the ability to reduce the 
surface activity of water can be of major importance. For example, it may 
be important during the installation or during the repair of an offshore 
oil recovery installation. It also may be important in facilitating a 
salvage operation. Excessive wave and current activity also can greatly 
hamper the recovery of petroleum constituting an oil spill or other 
floating contamination. 
It is an object of this invention to provide a practical method whereby it 
may be possible, wherever it may become desirable to do so, to provide in 
a particular area a body of water wherein the surface activity is 
substantially reduced in relation to adjoining water surface. 
According to this invention the surface activity of a body of water is 
reduced by providing a succession of booms at least partially surrounding 
it so that the surface of the body of water is substantially isolated by 
the presence of the booms in relation to the surface of water peripherally 
external with respect to the booms and surface activity of the so 
surrounded body of water is substantially reduced by subjecting the 
surface of the body of water to a cold or super cold substance or 
substances that chills the water at and adjacent the surface so as to 
increase the internal friction therein with possible formation of ice. The 
chilling may be accomplished by distributing on the surface of the body of 
water a material at a cryothermal temperature, namely, a temperature 
corresponding to the freezing point of the water at sea level or lower, 
the freezing point of sea water being substantially 29.degree. F. 
The material at cryothermal temperature may be a cryogenic material such as 
particles of solid carbon dioxide (dry ice) or droplets of liquid nitrogen 
that are distributed preferably so as to cascade down on the surface of 
the body of water. Alternatively, one may employ particles of solid carbon 
dioxide, or water ice particles chilled down by liquid nitrogen. 
Preferably the material at cryothermal temperature is produced from a 
stream of water by converting it into ice particles by some appropriate 
expedient such as contacting the stream of water with a cryogenic material 
such as liquid nitrogen or particles of solid carbon dioxide. The 
preferred method which likewise is the least costly is to project a stream 
of water through a nozzle so as to fall as a cascade on the surface of the 
body of water and either before or after it leaves the nozzle convert the 
stream of water into ice particles at a temperature considerably below the 
freezing point of the water. Means for projecting a stream of ice 
particles are well known as, for example, equipment of the type commonly 
used at ski areas to apply artifically produced snow to ski slopes. The 
material at cryogenic temperature ordinarily is distributed from a source 
such as a boat that is external with respect to the periphery of the 
succession of booms but is sufficiently adjacent to the succession of 
booms so that the material at cryothermal temperature may be projected for 
effective distribution on the surface of the body of water. To better 
accomplish such distribution the material may be projected from a 
plurality of projection sources and the source or sources may be movable 
relative to the booms. The material at cryothermal temperature preferably 
is projected so as to fall as a cascade onto the surface of the body of 
water. While it may be caused to fall as a cascade onto the surface of the 
water by projecting it horizontally or downwardly, it is ordinarily 
preferable to project it upwardly so as to get a better trajectory for 
wider distribution and so that it will fall more effectively as a rain or 
spray onto the surface of the water. When the material at a cryothermal 
temperature is distributed on the surface of the body of water as a 
cascade or rain comprising ice particles that fall on the body of water at 
substantial velocity, the resulting impact effect as well as the cold 
state of the particles acts to quell surface activity in much the same way 
that hail is effective to flatten the surface of the sea even in a high 
wind. 
It may be of some advantage to also chill down or even form ice spicules 
and crystals in water that is in adjacent peripherally external relation 
with respect to the booms, because any tendency of wave or current to 
agitate the surface of the body of water protected by the booms must first 
attack the external perimeter of the succession of booms. 
The succession of booms may be provided in different configurations 
depending on a given need. When there is wave action imparted by wind the 
direction of the wave action advance depends on the predominant direction 
of the wind. In such case the desired isolating effect provided by the 
boom does not necessarily require that the body of water be protected by 
completely surrounding it with the booms. For many purposes it is 
sufficient to provide a succession of booms along the windward margin of 
the body of water to be protected coupled with such additional booms as 
may be desirable to protect the sides of the body of water that extend 
rearwardly from the windward margin. Preferably, at least the major 
portion of the surface of the body of water is isolated by the presence of 
the booms in relation to water surface peripherally external with respect 
to the booms. In some instances it may actually be desirable to provide an 
opening in the succession of booms along a lee margin of the body of water 
so as to facilitate entry and exit of vessels carrying equipment of one 
kind or other for the task at hand. For example, in the case of an oil 
spill the area of the oil spill that is to be cleaned up may be isolated 
by a succession of booms that has an opening therein along or adjacent the 
lee margin for the introduction of equipment for use in cleaning up and 
recovering the spilled oil while the surface activity of the body of water 
is quieted down in the manner that has been described hereinabove. On the 
other hand, for certain purposes such as installation or repair of 
offshore oil recovery equipment it may be desirable to completely surround 
the body of water by the succession of booms while work is actually in 
progress. 
Usually when there is surface activity occasioned by wind or current any 
succession of booms that may be put in place tends to drift and for this 
reason the practice of this invention normally contemplates that the 
succession of booms will be moored by mooring means which maintains the 
booms in a substantially stationary location. Of course, if there is 
little or no tendency to drift or if the desired protection is of such 
short duration that a certain amount of drift may be tolerated, it would 
not be necessary to secure the booms to mooring means. 
The booms may be provided in any way that is the most convenient for the 
purposes. They may be made of wood, or in the form of elongated hollow 
metal bodies or in the form of elongated porous plastic bodies. The booms 
are ordinarily made so that they may be secured together in end-to-end 
pivotal relation by some securing means which permits ready attachment and 
detachment. While not essential to the practice of this invention, the 
booms preferably are provided so as to present a material at a cryothermal 
temperature on the surfaces thereof facing said body in position to be in 
contact with the water adjacent the surface thereof. A preferred practice 
in this regard is to attach rectangular blocks of solid carbon dioxide to 
the booms so as to face the body of water to be protected. Alternatively 
the booms may present a surface chilled by refrigeration. The chilling 
action provided by the material at cryothermal temperature that is 
presented by the booms in contact with the water serves to quiet the 
surface activity immediately adjacent the booms and thereby serves to 
substantially increase the effectiveness of the booms in accomplishing a 
reduction in surface activity in relation to surface activity of the water 
peripherally external with respect to the booms. 
One of the applications of the present invention wherein it is of great 
advantage to be able to reduce the surface activity of a body of water as 
herein described is in connection with attempts to clean up and recover 
petroleum oil that has been spilled on water. Any such attempt obviously 
is hampered by excessive wave or current activity and any technique for 
oil spill clean-up and recovery that may be employed is greatly benefited 
by reducing the surface activity to a minimum utilizing the method of this 
invention. 
In my U.S. Pat. No. 4,031,707 I have disclosed improved method and 
apparatus for cleaning up and recovering oil spills wherein the floating 
oil is herded utilizing booms that carry, so as to be in contact with the 
water at and adjacent the water surface, a cryothermal material of the 
character hereinabove described which preferably is in the form of 
elongated blocks of solid carbon dioxide. As aforesaid the oil floating on 
the water tends to be repelled by and moved away from the material at 
cryothermal temperature and as disclosed in said patent by disposing the 
booms with the material at cryothermal temperature facing the oil spill 
and by then advancing the booms toward the oil spill, the oil constituting 
the oil spill may be herded into any area where the oil constituting the 
oil spill becomes of greater concentration and more readily removed and 
recovered. While the oil constituting the oil spill can be successfully 
recovered when utilizing the method and apparatus described in my said 
patent notwithstanding substantial surface activity, the herding and 
recovery of the oil may be accomplished much more effectively and 
expeditiously when the method of the present invention also is availed of 
to quite the surface of the water on which the oil is floating. To this 
end, for example, the succession of booms which provide protection for the 
body of water to be cleaned up may comprise an opening in the lee margin 
thereof for permitting boom means to be moved therethrough so as to face 
the oil spill with the oil spill between said boom means and the 
succession of booms which ordinarily would be moored so as to be 
substantially stationary unless there is little tendency for the 
succession of booms to drift. Since the boom means that has been brought 
in carries the blocks of solid carbon dioxide or other material at a 
cryothermal temperature so as to face the oil spill, movement of the boom 
means toward the succession of booms causes the oil to move away from the 
solid carbon dioxide as it is advanced so as to accomplish herding of the 
floating oil into a more restricted confined area or region of the water 
surface protected by the succession of booms so as to enable it to be much 
more readily removed and recovered. The effectiveness of the herding and 
confining action between the movable boom means and the succession of 
booms that protect the body of water is furthered when, as is preferable, 
the booms comprised in the succession of booms also carry blocks of solid 
carbon dioxide or other material at a cryothermal temperature, which have 
the effect of causing the floating oil to be repelled therefrom. While the 
improvements in oil spill clean-up and recovery obtained in this way are 
to be regarded as within the purview of this invention, nevertheless in 
preferred practice the surface of the body of water having the oil spill 
thereon also is subjected to the cascading thereon of ice particles or to 
other distribution thereon of material at a cryothermal temperature 
thereby calming the surface activity as the boom means carrying the blocks 
of solid carbon dioxide is advanced thereby not only greatly facilitating 
the herding action but also causing the oil to be concentrated in a 
condition which by virtue of its lowered temperature facilitates its 
removal and recovery.

In FIG. 1 the body of water 10 is surrounded by a succession of booms 11 
which float on the surface of the water. As indicated in FIG. 2 some 
suitable means for readily securing the booms together in end-to-end 
pivotal relation may be employed. Preferably the means attaching the booms 
together is such that the attachment and detachment may be readily 
accomplished, as, for example, by the use of terminal ring pins 12 through 
which a pin 13 may pass, the pin 13 being prevented from accidental 
removal by the use of a cotter pin arrangement 14. Various other 
attachment devices may also be used such as swivelling pipe fittings or 
hose connections in conjunction with cables or chains. The booms 11 
ordinarily are prevented from drifting as, for example, by the securement 
thereto at the appropriate locations of lines 15 leading to mooring 
anchors 16 which hold the booms so as to remain substantially stationary. 
While the succession of booms has been shown disposed in the form of a 
rectangle it is to be understood that the configuration of the succession 
of booms may take any other shape as, for example, a circle or an oval. 
When the disposition of the booms is such that adjacent boom ends occur at 
a relatively sharp angle as indicated at 17 appropriate securing means may 
be employed such as a short length of chain (not shown) the ends of which 
have eyes which can be secured to the terminal ring pins 12. As shown in 
FIGS. 1 and 3 each of the booms may be in the form of a hollow cylinder 18 
which preferably has attached thereto the bracket 19 which, as shown, 
comprises a hollow float chamber 20 at the bottom that is of sufficient 
size to maintain the bracket 19 in position to hold the block of solid 
carbon dioxide 21 upright in contact with the surface of the water due to 
the buoyancy provided by the hollow float chamber 20. The boom 
construction as shown in my U.S. Pat. No. 4,031,707 also is suitable. 
Alternatively as shown in FIGS. 4 and 5 adjacent booms 35 may comprise a 
refrigerant coil 36 disposed so as to be in thermally conductive relation 
with the surface 37 of the booms so that by the flow of a refrigerant 
fluid at a cryothermal temperature through the coil 36 the material of the 
boom surface 37 may be maintained at a cryothermal temperature. In order 
to maintain the boom in the position shown the booms desirably are 
provided with an effective amount of ballast 41. As in FIG. 2 the ends of 
the booms may be interconnected by terminal ring pins 12 for cooperation 
with the pin 13 and the cotter pin arrangement 14. As mentioned 
hereinabove, other connecting means also may be employed. So that the 
regrigerant fluid may flow from the coil 36 in one boom to the coil 36 in 
an adjacent boom, a flexible hose 38 is provided having readily attachable 
and detachable connections 38' with oppositely disposed terminals of the 
coils 36. As illustrated in FIG. 1 a desired succession of booms may be 
provided with flow of refrigerant fluid at a cryothermal temperature that 
is supplied through a hose 39 from refrigerating apparatus aboard the 
vessel 31. Return flow from the refrigerated succession of booms may be 
provided by a return hose 40. Other booms by suitable hose connections may 
have refrigerant supplied there from the vessel 31 or some other vessel or 
vessels. For accomplishing the desired refrigeration conventional 
refrigerating systems may be employed. For example, a carbon dioxide or an 
ammonia refrigeration system could be used. Alternatively a mixture of dry 
ice and alcohol or a slurry of water and ice particles could be pumped 
through a desired succession of booms. 
When the succession of booms 11 has been moored so as to occur in the 
position illustrated it serves to isolate the surface of the body of water 
protected by the booms in relation to the surface of water that is 
peripherally external with respect to the booms. For example, in 
connection with the arrangement illustrated in FIG. 1 the advance of the 
wave action as impelled by the wind may approach the succession of booms 
from the top of the drawing so that the upper two margins of the 
succession of the booms are the windward margins that provide the 
principal protection for the body of water within the complete enclosure. 
In accordance with this invention when the isolating protection provided by 
the booms is supplemented by the distribution of a material at cryothermal 
temperature over a very substantial portion of the surface of the 
protected body of water, it is possible to greatly reduce surface 
activity. To this end, and as illustrating preferred practice, a vessel 31 
that is in external relation with respect to the succession of booms is 
provided with means for projecting the material at a cryothermal 
temperature so as to be cascaded onto the surface of the protected body of 
water. For this purpose any suitable equipment may be employed. For 
example, the vessel may be provided with powerful pumps such as those that 
are employed on fire boats which are capable of projecting a large stream 
of water through a nozzle so as to play over an extensive area. Prior to 
leaving the nozzle or just after having left the nozzle the water stream 
is contacted with a cryogenic substance such as solidified carbon dioxide 
in fine particle form or liquid nitrogen or any other substance or means 
by which the sea water or fresh water, as the case may be, may be 
converted to ice. As hereinabove mentioned another type of equipment which 
could be used is that which is used extensively to apply artificial snow 
to ski runs. Preferably as indicated the material at cryothermal 
temperature is projected from a plurality of nozzles or other sources and 
the material is projected upwardly at an angle which enables the material 
to cover as much of the surface area as possible and fall thereon with 
substantial velocity. The effect of the material at cryothermal 
temperature as cascaded onto the surface of the water, as aforesaid, is 
similar to that of a super cold hail which not only has the ability to 
flatten out an agitated sea but also to chill down the surface of the 
water, and to some extent the subsurface layers of water so as to enhance 
internal viscosity, the combined effect being to greatly reduce the 
surface activity of the water. 
While FIG. 1 does not show the presence in the protected body of water 10 
of any particular type of equipment, it is to be understood that the 
quieting of the surface activity of the water within the enclosure 
provided by the booms is such that it will facilitate the carrying out of 
any type of operation such as the installation or repair of equipment for 
oil recovery or the carrying out of a salvage operation. 
While in FIG. 1 the succession of booms is shown as completely surrounding 
the protected body of water 10 the practice of this invention contemplates 
that the body of water need not in all cases be completely surrounded by 
the succession of booms. For example, in the case of the arrangement shown 
in FIG. 1 the booms along a portion or all of the lee side of the 
protected body of water may be dispensed with. More particularly, the 
booms along the lower lefthand margin may be omitted at least temporarily 
as, for example, to permit the entrance and exit of equipment while at the 
same time enabling the surface activity of the protected body of water to 
be greatly reduced by the use of the method of this invention. 
An operation of the type which may advantageously be carried out, even 
though a portion of the succession of booms that is along a lee margin of 
the protected body of water has been omitted, is one for the purpose of 
cleaning up and recovering petroleum that constitutes an oil spill on 
water. Such an operation is illustrated in connection with the facilities 
shown in FIG. 6. For cleaning up and recovering an oil spill the 
succession of booms 22 is, of course, provided so as to be disposed for 
protecting as much as possible of the region where the oil spill occurs, 
there being booms along the windward margins 23 and 24 and also along one 
of the lee margins 25 thereby providing the protected body of water 26 so 
that the surface activity thereof is substantially isolated by the 
presence of the booms in relation to the surface of water that approaches 
the booms from the windward side. The booms are prevented from drifting by 
being mounted to the mooring anchor 32. The individual booms 22 are 
preferably of the type hereinabove described which include means for 
carrying so as to be presented in contact with the surface of the 
protected water blocks of solid carbon dioxide or other material at a 
cryothermal temperature which face the oil floating on the water between 
the booms 27 and the confinement afforded by the succession of booms 22. 
The booms 27 may thereafter be moved so as to advance them into the 
protected body of water 26 by some suitable means such as push-type boats 
28. As hereinabove mentioned the floating oil is repelled by the dry ice 
or other material at a cryothermal temperature presented by the forward 
faces of the booms and tends to move away therefrom with the result that 
the floating oil can be readily herded into a smaller area. For example, 
the oil may be hereded by moving the booms 27 to the position shown in 
dotted lines where it is confined into a much more restricted area from 
which it may be removed by some suitable means such as a suction or 
skimming device 29 so that the oil may be taken into a collecting vessel 
such as the barge 30. 
If the wave activity in external relation with respect to the succession of 
booms is not excessively heavy, the cleaning up and recovery of the oil 
spill may be accomplished as hereinabove described without additionally 
quelling the surface activity by cascading a material at cryothermal 
temperature onto the surface of the oil of the oil spill. However, the oil 
recovery is greatly facilitated when the reduction in surface activity 
afforded by the succession of booms is supplemented by cascading material 
at a cryothermal temperature, as from the ship 33, so as to fall onto the 
surface of the oil where the oil spill occurs as, for example, during the 
period when the booms 27 are being moved for concentrating the spilled oil 
into a more concentrated region or area and during the pick-up of the oil 
for transfer to a ship. Moreover, the chilling of the oil itself by 
increasing its surface tension serves to afford the oil in a condition 
which facilitates its recovery by an operation such as skimming or suction 
.