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138 Operation Channel Blast
by Robert Keller, Chief Warrant Officer, U. S. Marine Corps
141 The Seagoing Catamaran Ship
by Waller H. Michel
Edited by H. A. Seymour Captain, U. S. Navy
By Robert P. Keller Chief Warrant Officer U. S. Marine Corps
A channel, 55 yards in width, 130 yards in length was blasted at the Marine Corps Air Station, Kaneohe Bay, as a landing site for Landing Vehicle Tanks. The request for the work came from the Commanding General, First Marine Brigade.
After surveying the job, it was determined that 25 tons of demolition charges and 25,000 feet of detonating cord would be needed to cut a channel approximately 50 yards in width by 130 in length. Since the cost precluded the purchase of such explosive items, a request for light-cased, unhazardous, unserviceable explosive ordnance was submitted. The Chief of the Bureau of Naval Weapons approved the request by making available unserviceable ammunition which was scheduled to be dumped by Naval Ammunition Depot, Lualualei, Oahu, Hawaii. It consisted of 215 depth charges, 120 demolition charges, 700 TNT projection charges and 37,000 feet of detonating cord.
The channel site, having the characteristics of a fringing reef, consisted of lava and coral. It extended 150 yards from the shore and had a moderate gradient of 1:20. Four broad ridges, protruding 8 to 14 inches above the water at low tide, transversed the majority of the channel site. The width of the ridges ranged from 5 to 30 yards, and between them were located tidal pools, ranging from five to ten feet in diameter and six to ten feet in depth. The surf consisted of spilling and plunging breakers. These breakers ranged from five to ten feet in height. Two different currents were prevalent at the channel site. The first, a littoral current, traveled from three to nine o’clock. It extended to the bottom and had a velocity of five to six knots. The offshore current traveled in the opposite direction at approximately four knots, but did not extend to the bottom. A composite Explo-
sive Ordnance Demolition Platoon, supervised and directed by members of the Marine Corps Air Station Explosive Ordnance Team, was organized for the channel blasting operation.
The equipment used was as follows:
(1) Twelve-hundred feet of one-half-inch wire rope was used as a suspension line.
(2) Four 1,000-pound weights were utilized as anchors for the buoys and suspension lines.
(3) Two MK-1 buoys (approximately 36 inches in diameter) supported the line. These buoys were anchored to the weights by a one- inch steel cable, 150 feet long.
(4) One “A” frame, constructed of 6X6s, 14 feet long, was used in conjunction with the MK-1 buoys to support the suspension line.
(5) One snatch block was secured to the “A” frame by a sling through which the suspension line traveled.
(6) One TD-18A Tractor was used as a mobile beach anchor while the depth charges
were being moved to the demolition site.
(7) One float was constructed to provide support for one MK-9 depth charge in the water. It consisted of six small buoys, three of which were secured to each end of a 4X4, six feet long.
(8) Twenty MK-2 trailers were used to deliver the depth charges to the channel site.
(9) Six sets of double 70’s were used by the divers. One mobile compressor was available for filling the bottles.
(10) The demolition equipment utilized was two blasting machines, two galvanometers, two crimpers and 300 feet of firing wire.
The blasting operation consisted of four phases: Phase I involved the placing of equipment to move the MK-9 depth charges from the beach to the underwater site. Phase II involved the priming of explosive ordnance with detonating cord and Composition C-3. Phase III included the steps required to move the depth charges to the underwater site.
Needing a beach for Landing Vehicle Tanks, Marines of the First Marine Brigade blasted a channel out of the coral 5 5 yards in width and 135 yards in length. Here Marines slide initial charges down to the channel site.
Phase IV consisted of the techniques used to “tie-in” the charges for detonation.
In compliance with the instructions promulgated by the Chief of the Bureau of Naval Weapons, the first two shots were small (two depth charges) with succeeding shots increased until a maximum quantity could be reached without producing undesirable results. Fourteen charges were considered the maximum amount to safely detonate at one time. Blasting caps were not used in the water. The priming of the two main lines of detonating cord was accomplished on the beach.
The one-half-inch wire rope, used as the suspension line, was constructed of improved plow steel and had a breaking strength of 10.8 tons. (Weight of depth charge is 340 pounds.) Since human life and property would be endangered by rope failure, a safety factor of eight was applied in determining the safe working load. (Safe working load was approximately 1.2 tons.) FM 5-34, Engineer Field Data, was used as a guide for determining the above information. All units at the Marine Corps Air Station were notified approximately two hours before time of detonation. Road blocks and radio communications were established at critical points 15 minutes before time of detonation. The detonation occurred only when the area was cleared.
No maintenance problem existed with the equipment since mechanical devices were not utilized. The suspension line was thoroughly checked for breaks and periodically greased to prevent excessive rusting, the 1,000-pound weights had a tendency to move toward the beach when excessive force was applied by the TD-18A.
After the first attempt was made to detonate the depth charge, it was discovered that wave action washed the granular TNT out of the MK-6 booster. This problem was remedied by tamping one block of Composition C-3 at each end of the booster.
The action of the surf, coupled with the velocity of the current, prevented the use of mechanical devices; therefore, it was necessary to employ two divers wearing shoes to push the depth charges along the suspension line to the underwater site. It took an average of 15 minutes to place a charge and return to the beach. No problem was encountered in handcarrying the projector charges or demolition charges to an underwater site; however, the action of the surf and velocity of the current caused difficulty in keeping the charges in place, particularly the area along the beach.
During periods of extremely strong surf, difficulty was encountered in “tying in” the depth charges. However, the weight of the depth charge served as an anchor for the diver. Because of the light weight of the other charges, the divers had great difficulty in “tying in” and keeping the charges in place.
A maximum of 14 depth charges was placed in line approximately eight feet apart. The detonation cut a narrow channel approximately three yards in width, 40 yards in length, and one yard in depth. The detonation of 60 projector charges, consisting of six piles each and located at approximately eight- foot intervals, cut a narrow channel approximately three yards in width, 25 yards in length and one yard in depth. A great percentage of power was lost from these charges placed close to the shore because the action of the surf and current prevented adequate positioning and tamping.
The result of this operation led to the following conclusion:
(1) That mechanical devices could not be utilized.
(2) That pushing the depth charges underwater to the desired site by the SCUBA divers proved successful and practical.
(3) That placing the depth charges in line, eight feet apart, provided the best results.
(4) That the use of depth charges as the primary item for blasting was adequate. The weight of the charges prevented excessive movement underwater and served as an anchor for tying them in.
(5) That the use of projector charges and MK-14 demolition charges proved satisfactory for cutting the gradual slope on the beach. The light weight of these items precluded satisfactory results in strong surf.
(6) That the process of priming the charges with detonating cord provided maximum safety. This technique precluded the use of blasting caps in the water.
(7) That the use of Composition C-3 as a “sealer” and added booster increased an insurance of a high order detonation.
(8) That the use of safe practices and the
Amount of Explosive Ordnance Utilized
Type | Amount |
| Exp. Wt. | Total Exp. Wt. |
MK-9 Depth Charges | 191 |
| 190 | 36,290 |
7.2. Projector Charges | 200 |
| 30 | 6,000 |
MK-14 Demo. Charges | 50 |
| 50 | 2,500 |
Composition C-3 | 20 | cases | 36§ case | 720 |
Detonation Cord | 20,000 | feet | 6/# 1,000 | 120 |
Grand Total |
|
|
| 45,630 |
THE SEAGOING CATAMARAN | SHIP | Its | resurgence in the small boat field, |
By Walter H. Michel, Naval Architect,
Friede and Goldman, Incorporated.
(Reprinted from The Maritime Reporter)
adherence to safety precautions enhanced the success of the operation.
(9) That the use of light-case, unhazardous,
The catamaran vessel has had a very long but dormant life. Based on the simple principle of having two hulls (or more) parallel to each other, and separated some distance abeam by strongbacks or centerbody structure, the catamaran has a high degree of stability and seakeeping ability. The gradual discovery, in the small boat field, that this allows for greater installed power (either engine or sail) for higher yet safer speeds has caused a mushrooming of interest and use in the last decade.
However, in the category of larger, seagoing ships, the record remains meager. There have been only a few such catamarans ever built and operated, and unfortunately the most notable and publicized of these had the misfortunes of being failures.
unserviceable, explosive ordnance (in place of demolition charges) proved very practical and extremely successful in this operation.
tending successfully in the past few years into the area of medium-sized oceangoing yachts, has called for another look at the catamaran ship. Such another look was initiated by a request from the Marine Laboratory of Miami University for Friede & Goldman, Inc., to undertake a feasibility study of a catamaran oceanographic vessel.
The catamaran generally has been considered to have inherently greater resistance than an equivalent single hull vessel, because of its two hulls. This is true in the range of slow speeds or extremely high speeds, but not in the intermediate range where wave resistance is predominant.
These speed ranges may be broadly identified as follows:
The slow-speed displacement range, in which most cargo vessels and large passenger liners operate. In this range, the frictional resistance of the wetted hull surface is pre-
dominant, with wave-making or residual resistance considerably less in magnitude. Speed/length ratios typically have the value of 1.0 or lower.
The high-speed displacement range, in which medium-sized passenger vessels, destroyers and escort vessels, and many types of special-purpose vessels operate. In this range, the wave-making resistance increases in relative magnitude, and predominates markedly over the frictional resistance for the higher speed/length values. Here, speed/length ratios are about 1.0 to 2.0, approaching 2.5.
The planning range, with speed/length ratios of 2.5 and up. In this range, fast pleasure craft, high-speed naval auxiliaries, and similar high power/weight vessels operate. Here, resistance is a combination of hydrodynamic inertial effects and surface friction, with the gravity effect of wave-making resistance virtually disappearing.
We are concerned principally with the seagoing ship, of a size and use where the economics of machinery cost and fuel consumption must be considered, and it is in the highspeed displacement range where the catamaran shows to advantage in this regard. Here the slenderness of the two “half hulls” causes such an appreciable reduction in wavemaking resistance that the over-all resistance may be lower than that of the single hull, despite the interference effect between the two hulls (which effect increases the wavemaking resistance, to a greater or lesser degree, depending on the hull separation).
For the feasibility study of the catamaran oceanographic vessel, resistance tests were conducted at the Davidson Laboratory of Stevens Institute on a model of a vessel having the following characteristics:
L.B.P.................................................. 130 feet 0 inches
Beam (each hull)................................. 16 feet 0 inches
Draft................................................... 8 feet 0 inches
Displacement (totcil).......................... 502 long tons
Cb....................................................................... 0.528
Cp....................................................................... 0.572
Wetted Surf, (total)........................... 5,276 square feet
Tests were run with clear separations between the hulls of 16 feet, 20 feet, 28 feet, and on a single hull, corresponding to separation/ beam ratio of 1.0, 1.25, 1.75 and infinity, respectively. The results of these tests, expressed in effective horsepower, are shown in Figure 1.
It might have been expected that the interference effect would diminish direedy with an increase in separation, yet surprisingly, the ratio of 1.25 has less resistance than 1.75.
The rather inherent requirement that a catamaran ship be twin-screw is not a limiting or unfavorable consideration, since most conventional displacement ships operating in the high speed/length ranges are twin-screw due to considerations of propeller loading. Actually, therefore, the catamaran ship might well be expected to have a higher propulsive efficiency in this range, since its propellers will each be operating in a more favorable stern wake than will those of the conventional ship, which are set well outboard of centerline, clear of the major wake area.
The exploratory tests indicate that, on the basis of resistance and propulsive efficiency alone, the catamaran ship holds definite promise of superiority over conventional ships in the range of speed/length ratios over 1.0.
From the standpoint of utility, probably the most outstanding feature of the catamaran ship is the large usable deck area it affords. The centerbody that bridges the gap between the two hulls adds a considerable amount of usable deck space, as working area and/or accommodations, depending on its intended purpose. Further, additional superstructure can be added as desired, without the usual limitations set by stability considerations.
The success of the catamaran in the small boat field is due to its inherent stability and seakeeping characteristics. These same inherent characteristics are displayed in the larger oceangoing catamaran ship.
In pure rolling condition, the wide spread of the hulls makes the catamaran exceptionally stable. Its resultant low natural period of roll eliminates the danger of synchronous rolling to large angles in waves of any appreciable size. Rather, it acts much like a raft, tending to follow the surface of the sea at all times.
The pitching characteristics of the catamaran ship are essentially the same as those of the conventional single-hull ship of the same basic particulars. There is, however, one particular difference. When pitching action is large, the waves striking the centerbody develop impact forces. These forces tend to reduce the pitching amplitude.
By virtue of its physical arrangement, the
catamaran may incorporate certain features without seriously affecting its basic hull design, such as:
(1)Ramps for handling cargo or vehicles.
(2) Wells can be incorporated into the center structure.
(3) Loading of cargo can be accomplished with little concern about balancing transversely to minimize heel.
(4) Shallow draft can be easily incorporated.
(5) Beaching operations should be more successfully undertaken.
(6) Helicopter accommodations are relatively easy to have incorporated into the design.
The catamaran ship does not come without faults. It offers greater hull resistance in the slow-speed ranges. For vessels where high speeds are important, these are achieved with less installed horsepower and less fuel consumption.
The presence of the centerbody structure adds to the structural weight, increasing the cost and reducing the deadweight capacity for a given size.
Several particular disadvantages are:
(1) The area exposed to sea, wind and weather is from two to three times that of the single-hull vessel.
(2) It requires two separate power plants, two separate hull piping systems, steering gear and general hull outfit.
(3) The two separate engine rooms could mean more crew.
As a final word, it must be concluded that the reappearance of seagoing catamaran ships is close at hand, and this time permanently.
Notebook
U. S. Navy
Increase Requested for Quarters Allowance: Proposed legislation designed to amend the Career Compensation Act of 1949 was sent to the Congress today by the Secretary of Defense.
It would provide an increase in the basic allowance for quarters (BAQ) for members of the uniformed services to meet the increased cost of housing in civilian communities.
Current basic allowances for quarters are essentially those established by the Act of May 19,1952, which represented a 14 per cent increase over then existing allowances, the approximate increase in housing costs during the period 1949-52.
The proposed increases in BAQ are based in large part upon those recommended by the Advisory Panel on Military Family Housing Policies and Practices in its report of November 15, 1961. Concerned with the problem of providing adequate family housing for military personnel, Secretary McNamara appointed this panel on October 4,1961, to conduct an intensive reappraisal of all the policies and criteria governing family housing, including requirements, standards, financing, and management.
The allowances for each grade in the proposed legislation are based on current housing costs paid by civilians of comparable income levels. Data from numerous government agencies, including Census, Federal Housing Administration, and Bureau of Labor Statistics, were utilized.
There is no appreciable increase recommended for the lower enlisted pay grades. Present rates for the lower grades are considered reasonable, based on housing expenditures by comparable civilian income groups and actual figures reported by personnel. The largest increases proposed are in the top enlisted grades of E-8 and E-9 amounting to 49% for a serviceman with one or two dependents and 66% for one without de-
Military Housing Allowances
| Grade Title | Present YVithout Dependents | Recommended YVithout Dependents | % Increase | Present YVith Dependents | Recommended YVith Dependents | % Increase |
0-10 | General | 136.80 | 160.20 | (17) | 171.00 | 201.00 | (17) |
0-9 | Lt. General | 136.80 | 160.20 | (17) | 171.00 | 201.00 | (17) |
0-8 | Maj. General | 136.80 | 160.20 | (17) | 171.00 | 201.00 | (17) |
0-7 | Brig. Gen. | 136.80 | 160.20 | (17) | 171.00 | 201.00 | (17) |
0-6 | Colonel | 119.70 | 140.10 | (17) | 136.80 | 170.10 | (24) |
0-5 | Lt. Colonel | 102.60 | 130.20 | (27) | 136.80 | 157.50 | (15) |
0-4 | Major | 94.20 | 120.00 | (27) | 119.70 | 145.05 | (21) |
0-3 | Captain | 85.50 | 105.00 | (22) | 102.60 | 130.05 | (27) |
0-2 | 1st Lt. | 77.10 | 95.10 | (23) | 94.20 | 120.00 | (27) |
0-1 | 2nd Lt. | 68.40 | 85.20 | (24) | 85.50 | 110.10 | (29) |
YV-4 | Chief YV.O. | 94.20 | 120.00 | (27) | 119.70 | 145.05 | (21) |
YV-3 | Chief YV.O. | 85.50 | 105.00 | (22) | 102.60 | 130.05 | (27) |
YV-2 | Chief YV.O. | 77.10 | 95.10 | (23) | 94.20 | 120.00 | (27) |
YV-1 | YVarrant Off. | 68.40 | 85.20 | (24) | 85.50 | 110.10 | (29) |
Military Housing Allowances
|
|
| Recommended |
|
|
Enlisted Personnel | Without % Dependents Increase | With 1 With 2 Dependent Dependents | % Increase | With 3 „ or More . 0 Dependents ncr' | |
E-9 | Sgt. Major | 85.20 (66) | 115.20 | (49) | 125.10 (29) |
E-8 | 1st Sgt/MSgt | 85.20 (66) | 115.20 | (49) | 125.10 (29) |
E-7 | Plat Sgt/SFC | 75.00 (46) | 102.60 | (33) | 120.00 (24) |
E-6 | Staff Sgt | 70.20 (37) | 96.90 | (26) | 115.20 (19) |
E-5 | Sgt | 70.20 (37) | 96.90 | (26) | 110.10 (14) |
E-4 | CpP | 70.20 (37) | 96.90 | (26) | 110.10 e (14) |
E-4 | Cpl2 | 60.00 (17) | *60.00 77.10 | ( 0) | 96.90 ( 0) |
E-3 | Pfc | 55.20 ( 8) | 55.20 (8) 77.10 | ( 0) | 96.90 ( 0) |
E-2 | Pvt | 55.20 ( 8) | 55.20 (8) 77.10 | ( 0) | 96.90 ( 0) |
E-l | Recruit | 55.20 ( 8) | 55.20 (8) 77.10 | ( 0) | 96.90 ( 0) |
* Savings clause recommended to prevent reduction in BAQ for current E-4’s. |
| ||||
1 With 4 or More Years. 2 With Less than 4 Years. |
|
|
| ||
( | ) Recommended percentage increase. |
|
|
| |
|
|
| Present |
|
|
Enlisted Personnel | Without | With 1 | With 2 | With | |
|
| Dependents | Dependent Dependents | 3 or more Dependents | |
E-9 | Sgt. Major | 51.30 | 77.10 | 77.10 | 96.90 |
E-8 | 1st Sgt/MSgt | 51.30 | 77.10 | 77.10 | 96.90 |
E-7 | Plat Sgt/SFC | 51.30 | 77.10 | 77.10 | 96.90 |
E-6 | Staff Sgt | 51.30 | 77.10 | 77.10 | 96.90 |
E-5 | Sgt | 51.30 | 77.10 | 77.10 | 96.90 |
E-4 | CpP | 51.30 | 77.10 | 77.10 | 96.90 |
E-4 | Cpl2 | 51.30 | 77.10 | 77.10 | 96.90 |
E-3 | Pfc | 51.30 | 51.30 | 77.10 | 96.90 |
E-2 | Pvt | 51.30 | 51.30 | 77.10 | 96.90 |
E-l | Recruit | 51.30 | 51.30 | 77.10 | 96.90 |
1 With 4 or More Years.
2 With Less than 4 Years.
( ) Recommended percentage increase.
(Dept, of Defense Office of Public Affairs, 19 March 1962.)
pendents.
The proposed rate structure also reflects these basic proposals of the Housing Panel: (1) Differentials by grade in the enlisted rate structure, as is currendy the case in the officer structure; and (2) two separate allowances in pay grade E-4, intended as a re-enlistment incentive at the end of the first four years of service.
The requirement for quarters allowance was first recognized in the Act of June 18, 1878, which provided an allowance for Army officers stationed at places where no government quarters were available. A similar provision for the Navy was passed in 1899.
Although a family housing construction program is a part of the Department of Defense Legislative Program, there will always be military personnel for whom government housing is not available, such as many stationed in large metropolitan areas. As of June 30, 1961, 61% of married members eligible for public quarters in the United States were living off the post on the local economy.
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WRENCHES
Other U. S. Services
Army Makes New Anchor: Army Engineers have combined solid rocket fuel and a revolutionary design to develop an explosive-driven anchor—one of the few basic changes in anchor design in many years. This special purpose anchor, developed by the U. S. Army Engineer Research and Development Laboratories, Fort Belvoir, Va., does not eliminate the need for the conventional anchor carried by ships. Rather, it is part of a system designed to provide secure mooring in offshore open-sea areas from which oil tankers can discharge oil through undersea pipelines.
The mooring system consists of a platform- type buoy, fitted with a pipeline in its base, and the anchor. The buoy is towed into position and the anchor is released by remote control. The solid rocket fuel detonates when the anchor contacts the floor and drives the anchor into the ocean floor; latest tests show a 34-foot penetration into a hard bottom.
T ankers simply moor themselves to the buoy, attach their pipelines, and start pumping oil. If it becomes necessary to abandon the site in a hurry, the buoy may be cut loose and the anchor left in the ocean floor. Because of its relatively low cost, it is considered expendable.
The Army Engineers, co-operating with the Navy and private industry, tested experimental mooring anchors weighing 225 pounds with a minimum holding power of 50,000 pounds, on sand, silt, coral, and rock bottoms. Results of these tests are expected to lead to the development of similar explosive-driven anchors weighing approximately 1,500 pounds with a holding power of 300.000 pounds,
which would do the job of the conventional- type anchor of equal holding power, but weighing 42,000 pounds.
The contract development program was under the direction of the Advance Systems Development Division of the Pneumo Dynamics Corporation, El Segundo, California.
(Naval Research Reviews, March 1962.)
Maritime General
Collision Notes: In a recent collision case involving two vessels in a crossing situation, the Commandant, upon review, found the privileged vessel to be at fault for failure to maintain course and speed. The record indicated that the pilot of the privileged vessel sounded two separate one-blast signals. After hearing no reply from the burdened vessel he stopped his engines. The following remarks are quoted from the Commandant’s Action with respect to this point and are considered self-explanatory:
“The purpose of Article 21 is to remove from the potentially hazardous crossing situation as much uncertainty as possible. It accomplishes this by requiring the privileged vessel to maintain its course and speed, thus enabling the burdened vessel to determine, with some assurance, the action best designed to meet her own obligation to stay clear. Only when the situation deteriorates to such an extent that the privileged vessel knows (or should know) that some different action is required lest a collision become inevitable can she ignore the mandate of the statute. This point is not reached merely when compliance becomes inconvenient, nor when anxiety occurs in the mind of the person in charge of the privileged vessel, nor even when he begins to doubt the intention of the other vessel. Nor does he have any right to rely on a speculation that the burdened vessel may not meet her obligation to stay clear.
“Only when there is reasonable certainty that the other vessel is not going to avoid, or cannot avoid, a threatened collision by her unaided action alone is the privileged vessel entided to invoke Article 27 and take whatever different action may be necessary. To allow any earlier departure from the requirements of Article 21 would defeat its very purpose. It would not remove uncertainty, but compound it. Instead of assisting in avoiding a collision, it might cause, or contribute to, it. That was the result in this case.” {Proceedings of the Merchant Marine Council, March 1962.)
Gulf Stream: There is an appalling ignorance on the part of many boatmen, fishermen, and landlubbers as to the nature, the cause, the width, the depth, the temperature, etc., of the mighty river in the ocean that flows within three miles of Fort Lauderdale’s coastline— the Gulf Stream.
Few people realize that because it flows so close to our shore we are blessed with one of the finest climates. As a matter of fact, the very existence of the Gulf Stream has been known for less than 200 years. That versatile early American, Benjamin Franklin, was one of the first to become scientifically curious about it, and it was his investigating spirit which led to the general recognition that such a natural marvel existed.
In brief, the Gulf Stream is caused by the rotation of the earth on its axis. The liquid mass of the Atlantic Ocean tends to lag behind on the surface of the eternally eastward whirling sphere of the earth. This lag is, of course, most evident near the equator and causes the water to pile up toward the east coast of South America. The northwestward slant of the Brazilian Coast fends it off toward the north into the Caribbean and the Gulf of Mexico. Circling around the Gulf, the moving mass of water is now far enough away from the equator so that the centrifugal force which started it on its way has considerably diminished. Seeking an exit from the Gulf, it finds its way as a narrowed stream through the channel between Cuba and Key West known as the Florida Strait. Issuing from the latter at a speed of 70 miles per day, this 50- mile wide mass of warm, dark blue water proceeds up the coast of Florida, widening and slowing its speed as it goes. Its warmth, of course, comes from the equatorial sun. Its 3,000-foot depth enables it to continue to give off a tremendous quantity of heat throughout its course. It has been estimated that it would take the burning of two million tons of coal per minute to produce a similar quantity of heat. The immense volume of the Stream is difficult to realize. By comparison, the Amazon and Mississippi are mere dribbles.
As the Gulf Stream passes Fort Lauderdale, it is an indigo mass of water plainly distinguished by its color from the murky green ocean on both sides. Its westerly edge is only a short distance off shore, and its influence serves to keep our summer and winter temperatures within a relatively narrow range. North of Palm Beach, the shelving ocean floor causes it to swing away from the coast with the result that the northern part of the east coast of Florida gets winter temperatures that are sometimes colder than a few miles of latitude would account for.
From Fort Lauderdale Beach nearly all the southbound vessels, visible to the naked eye, stay inside the Stream’s westerly edge in order to avoid bucking the current. Northbound ships, however, get well into the Stream to take advantage of its movement.
A great deal more could be written about its effect on aquatic life, its steady flow in an ever widening stream until is it deflected by the Polar currents toward the British Isles and Scandinavia, tempering the climate of these countries which would otherwise be as cold as Labrador. {Ensign, March 1962.)
CENTER OF NAVAL ANALYSES
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"For 20 years, the Navy has consistently been the first of the services to foresee the opportunities for operations research and the requirements on its part to assure its success"—Dr. Jacinto Steinhardt, OEG director, at the OEG Vicennial conference.
OEG's technical management has been transferred to the Franklin Institute. We will operate as a part of the new Center of Naval Analyses, in a role that promises to be broader than our former one. Having just celebrated its 20th anniversary of work for the U. S. Navy, OEG looks forward to an even more productive future.
One of our analysts has returned from field assignment with the fleet and told us a significant improvement resulted when one of his recommendations was put into practice during fleet maneuvers.
OEG’s field activities, assigned on a rotational basis, represent unique travel opportunities for scientists and mathematicians.
There are OEG men with the fleet in the Mediterranean, the Far East, Hawaii, Key West,
Norfolk, and San Diego, and field representatives in Newport, R. I. and London, England.
for Scientists, Mathematicians Operations Evaluation Group
TECH NEWS
Television for Port Maneuvers: The docking and maneuvering in port of very large tankers and bulk carriers with navigating bridge aft, presents many problems to ship’s officers and pilots. Chief among these is the problem of discerning objects ahead which are screened from view by the bow.
One method of overcoming this disadvantage is by providing a midship navigating position, but this would entail further work at the construction stage, duplicity of controls, and danger in rough weather. The ideal solution, therefore, appears to lie in closed-circuit television.
Experiments were recently carried out by the Marconi International Marine Communication Co., Ltd., Chelmsford, on two tankers owned by Messrs. Common Brothers, Ltd. In these experiments a television camera in a weatherproof casing was fitted right up in the bow, with one monitor receiver in the wheelhouse and a second, with the camera control gear, in the radar room abaft the bridge. The camera was of the pan-and-tilt type, being remotely controlled from the radar room.
The equipment was switched on before the ship cast off, and it was noted on the monitor screen that a small craft was lying ahead although not visible from the bridge. Leaving the berth and proceeding out to sea, the ahead tugs were frequently obscured by the forecasde head but clearly visible on the monitor screens. During these experimental trials it was also established that the system worked well by night.
There seems little doubt that this system will give a new meaning to the term, “the eyes of the ship,” and will provide a major contribution to the safety of ships and lives. In an actual permanent installation the television camera would be built into a compartment in the bow. (The Shipbuilder and Marine Engine Builder, March 1962.)
Space
Gemini Unveiled: A full-scale model of the Gemini spacecraft designed to take two astronauts into orbit for a week or more was unveiled Thursday. It could play a major role in manned flights to the moon.
The Gemini is designed as an operational craft rather than as a research vehicle.
The wooden and glass mockup is larger but quite similar in appearance to the bellshaped Mercury capsule used in America’s manned space shots. The Mercury has only one-day orbital capabilities.
Gemini, under development by McDonnell Aircraft Corp., which built and designed the Mercury, will be used primarily to develop space-flight rendezvous techniques. A rendezvous in orbit with another space vehicle carrying a booster is one method under consideration by the National Aeronautics and Space Administration for carrying out manned expeditions to the moon later in this decade.
The Gemini model does not include a wing—described as wedge-shaped—which will be used to bring it back to earth in a guided, controlled landing.
Nor is it equipped with a three-legged skid-type landing gear, which is under design.
The Gemini will have a propulsive engine enabling it to maneuver in space so that it can join another orbiting vehicle.
The Gemini provides 50 per cent more cabin space and will be from two to three times heavier than the one-ton Mercury. It is 11 feet high and 7§ feet in diameter at the base.
Small windows are provided for each of its astronauts, who will recline on a couch, as the case with one pilot in the Mercury capsule.
The Gemini will be launched by the 90- foot-high two-stage Titan II, which was recently successfully tested. This would follow the launching of a slightly taller Atlas Agena B assembly. Through use of tracking stations, the Gemini and Agena B rockets will be placed in similar orbits for their space meeting.
Scientists advocating the rendezvous method have expressed belief successful development of such a technique will speed up a landing on the moon. A nonstop moon shot, using the three-man Apollo spacecraft, would require a monster rocket not yet designed. (The Virginian-Pilot, 30 March 1962.)
SSTVinQ OUT Cjlobol nsvy With U.S. Navy Forces on the seven seas go auxiliary vessels built by Sun Ship in direct support of fleet capabilities. In peace and war, Sun Ship has long occupied a leading position in designing and constructing vessels which have been of important service to the Navy.
Sun is proud of its contribution to national security.
SHIPBUILDING & DRY DOCK COMPANY
ON THE DELAWARE . SINCE 1916 . CHESTER, PA.
Edited by H. A. Seymour Captain, U. S. Navy
Telescopic helicopter hangar —Canada’s Department of Transport produced this unique hangar (left). It can be retracted to nine feet six inches to permit a helicopter to land and it can be extended to almost 50 feet to completely enclose the craft. It is in use aboard CMS C. D. Howe.
SS Manhattan—Largest merchant vessel ever built in the United States and the largest to fly the American flag, she is 940 feet long with a deadweight of 106,568 tons. She has a liquid cargo capacity of over 38 million gallons and a service speed of over 17 knots. Manhattan is compared with a standard T-2 tanker in the left foreground.
Contrail-suppressor—The two bombers (right) show the effect of the new contrail-suppressor. Bomber on left has none. Bomber at right has suppressors on left engines. Contrails have long betrayed the presence of high-flying bombers.