From Florida to Cape Cod - Without Moving
- Text of the Popular Mechanics Article by Wallace Cloud-
- Text of the Popular Mechanics Article by Wallace Cloud-
From Florida to Cape Code - Without Moving
Hitchhiking a ride on the Gulf Stream, Dr. Jacques Piccard will turn off the motors of his unique submarine and drift on an amazing underwater voyage.
by Wallace Cloud
When I climbed up the sloping deck of the submarine from a rubber boat, she was in the last stages of fitting out at West Palm Beach. (It seems awkward to call a sub named Ben Franklin "she", but there's no way around it.) By now test dives have taken place, and soon she'll be towed out to sea, with Jacques Piccard, a Grumman skipper, and Navy scientists aboard. The Franklin will sink and remain submerged for a month or more, slowly drifting some 1500 miles up the Gulf Stream like an undersea Kon-Tiki.
Throughout the voyage, Dr. Piccard told me, the sub may remain in the same cubic mile of seawater as it moves from Florida to the vicinity of Cape Cod. In the gloom 300 to 2000 feet below the surface; the six men aboard will get to know that volume of water intimately. They will monitor its changes in temperature; observe the intrusion and diffusion of surrounding water; and watch the marine creatures that enter and leave their moving cell of fluid. In a submarine that floats soundlessly at any depth down to 2000 feet; they will become a part of the Gulf Stream; that river in the sea that carries 22 times as much water as all the land rivers of the world. Under tons of pressure, they must trust the Gulf Stream to take them for a ride; they will trust their vessel, designed by Grumman Aircraft Engineering Corp. and Dr. Piccard, to bring them safely through it.
A man of enormous drive, Piccard has already been to the deepest spot in the ocean, the bottom of the Marianas Trench, 35,800 feet down in the Pacific. He went there for the U.S. Navy in the bathyscaphe Trieste, which he designed with his father, Prof. Auguste Piccard, the famous stratosphere balloonist.
Before christening, the Ben Franklin was designated PX-15the 15th Piccard experimental design- The numbers start from the world's first bathyscaphe, FNRS-3, which the Piccards built for the French Navy. Trieste was their next bathyscaphe. Another vessel, the Auguste Piccard; built in 1963, carried 30,000 sightseers into the depths of Lake Geneva.
In September, 1964, Piccard announced plans for the Gulf Stream drift. He didn't know where the funds might come frombut then along came Grumman Aircraft Engineering Corp. Construction of the PX-15 began in March, 1967, at Monthey, Switzerland. Grumman has spent $2-5 million on the project so far, owns the Ben Franklin, and employs Piccard as a full-time consultant.
The Naval Oceanographic Office, which is participating in the Gulf Stream mission, is the first "customer" to use the Franklina "mesoscaphe" or submarine designed for middle depths. Her maximum cruising depth is 2000 feet.
When I visited the sub at Palm Beach, engineers were busy making sure the boat will do everything required of her. Mooring lines held the yellow-and-white sub well out from the concrete bulkheads of her slip. She rolled a surprising amount, and that was the simplest way to avoid damage to the fiberglass ballast tanks and the motors, which project at the sides, said her skipper, Don Kazimir; a former Navy submariner.
The Ben Franklin, although a highly sophisticated research vessel, is surprisingly simple in design. Her pressure hull is a cylinder 10 feet in diameter, stiffened with 16 rings inside and capped with hemispherical ends, all welded of l 3/8-inch high-strength steel.
Total length is 48 feet 9 inches. Slung beneath the hull is a "keel" consisting mainly of 26 tons of lead-acid storage batteries in an aluminum framework. Above the hull is a narrow metal deck, with a small conning tower forward. Bulging below the sides of the deck are ballast tanks. Four swiveling 25-hp electric motors jut from the sides of the hull at each end.
Inside, the sub was like a long corridor lined with bunks, workbenches and electrical gear. A portable air conditioner on the dock was blowing cold air into the forward hatch. Florida sunshine penetrated the clear water outside to pour through the three-inch-thick plexiglass windows in the ends of the hull (there are 29 viewports in all). Kazimir said a community of barnacles had already adopted the Franklin, some living comfortably on antifouling paint around the portholes. With no way to get out and wipe the windows, it's a question how good visibility will be by the end of the trip.
In the cockpit, engineers were checking out motor controls and power circuits. Divers beneath the hull were spotting faulty electrical connectors which had to be replaced before test dives could begin. Using electrical equipment in saltwater is the biggest operational difficulty facing the crew, Piccard told me.
Going through the hatch, I noticed a sign reminding technicians that all objects placed aboard or removed had to be weighed; Later; I mentioned this to Dr. Piccard. "We must have an exact record;" he said; "of the boat's weight; in order to calculate the ballast; It the submarine is one pound too light; we will never be able to sink; If we arc one pound too heavy; we will never come up."
He explained that the Submarine is designed to "float" at any depth down to its 2000-foot limit without pumping water in or out of the ballast tanks. This is because the submarine's pressure hull is less compressible than water.
All conventional submarines; including nuclear subs. are more compressible than water. That means that as the sub descends, its hull is squeezed to slightly smaller volume by sea pressure. Not much can be done about this in a military submarine, Dr; Piccard said, because the weight of equipment and armament limits the weight, and therefore the rigidity, of the pressure hull. Of course a nuclear sub. with virtually unlimited power, can "hover" by pumping ballast, or use its motor to "fly" at a desired depth. But in a research submarine weight can be carefully regulated in relation to the size and stiffness of the hull to create a design that can be balanced to neutral density at a wide range of depths. (A pound of water added or subtracted makes the Ben Franklin descend or rise exactly 10 feet.) This is what makes the Gulf Stream drift possible; otherwise the power available would limit how long the sub could stay down.
Hull construction remarkable
The Franklin's pressure hull alone is a wondrous job of engineering. It was fabricated by bending and welding together 20 massive pieces of steelsix cylindrical sections and the two hemispheres, each made of seven segments. These were reinforced with 16 welded stiffening rings. Cast-steel reinforcement plates were added wherever there were portholes or penetrations for electrical cables or piping. A variety of clips, brackets and attachment points, designed to support equipment inside and outside, were welded in place. In all, 1000 items were welded into the hull.
All that welding introduced stresses. These were relieved by cooking the entire hull in a giant electric oven at almost 1000 F for several days and letting it cool slowly. Then all the welds were X-rayed and tested ultrasonically. and the hull was measured all over to make sure nothing was out of line more than about 3/8 inch. So careful was the work that no imperfections were found by an American Bureau of Shipping inspector. The hull's collapse depth is 4000 feet.
The hull is in two pieces bolted together at a flange joint aft of amidships. The forward section contains all controls, electrical gear, galley, head and shower. The after section contains five of the six bunks, workbenches and space for scientific equipment. It can be removed and a new one bolted in place for a different sort of mission. This might be, for example, a lock-out diving chamber that can be pressurized while the forward section remains at sea-level pressure.
Aside from the hull, electrical equipment constitutes the heaviest part of the Ben Franklin. The 378 batteries make up close to 25 percent of the sub's weight. It was logical to place them in the keel, where their weight keeps the sub upright. In this free-flooding section, the batteries must be sealed against scawater, yet able to release hydrogen gas given off during operation. That's done in smaller research subs by encasing the batteries in an oil bath. To save weight, the Franklin's batteries are vented through a manifold of oil-filled tubes leading to a single duckbill valve.
Battery power, totaling 756 killowatt-hours, is available in four different voltages: 168 volts for the motors that swivel the main propulsion motors. 336 volts for the main motors, 112 volts for the lamps that light up the sea around the Franklin 70 powerful searchlights and 28 volts for on-board equipment. The sub's motors. running on a.c. for better control, require inverters and switching gear that take up a good deal of space.
The four motors provide a top speed of five knots, but are intended for maneuverability. rather than speed. Since they can be pointed forward or back. up or down, the sub can turn or tilt every which way. During the mission the motors will be used mostly to get back into the mainstream if the Franklin should drift into one of the Gulf Stream's branches. Here's what the mission will be like. as far as Dr. Piccard can visualize it beforehand.
The Ben Franklin will be towed out to sea with her crew aboard, said Dr. Piccard. The western edge of the great current is only a mile offshore near Palm Beach, so the tow will be shortfortunately, since the sub's surface behavior is less than ideal. Aboard will be Piccard, Kazimir and Erwin Aebersold, a Swiss associate of Piccard's, as pilot. Three U.S. Navy scientists will be headed by Frank Busby of the Naval Oceanographic Office;
After hatches have been sealed and final checkout performed- the sub will submerge. First will come complete flooding of the "soft" fiberglass ballast tanks which provide surface flotation. Next, a carefully calculated amount of water will be let into the two "hard" (pressure-resistant) ballast tanks in the keel which hold about 100 gallons;
The dive will be slow. After a gradual descent, during which ballast will probably be pumped to arrive at approximately the right depth, an even slower settling will take place as the sub cools off to the temperature of the water. It's expected that 24 hours will elapse before the Franklin finishes contracting as it cools and reaches a state of neutral buoyancy.
Since the water here is of continental-shelf deptha few hundred feet offshore, gently sloping out to seaduring the first half of the mission the sub will be drifting at fairly shallow depths300 to 600 feet. Several excursions to the bottom will be made to take pictures of undersea topography; The sub will be equipped for 35-mm movie-making and still photography. The excursions will take place during the first half of the trip, because north of Cape Hatteras the Gulf Stream veers off over a bottom more than 10:000 feet deep.
Piccard plans to stay close to the west wall of the Gulf Stream. Since the water temperature in the current increases to the east, he could conceivably navigate by monitoring the temperature and periodically adjusting position to the desired temperature line. But this would not provide position data accurate enough for scientific measurements. For that data, the sub will rely on two surface ships supplied by the Navy, and contact them by means of a sound-powered underwater telephone.
The men aboard the sub will be able to deliver items to the surface. A small air-lock in the top of the hull is designed for release of five-inch aluminum spheres in which rolls of film, tape cartridges, written notes or small specimens of marine life can pop to the surface.
Daily drift 36 to 48 miles
Drifting with the current, the Franklin will average 1.5 to 2 knots, and make 36 to 48 nautical miles a day. At the surface; the Gulf Stream has an average speed of 4 knots. This means that the surface ships, in order to remain above the sub, will travel 1500 miles northward by steaming south.
"Our life on board will be relatively comfortable." says Piccard. "Each man has his own bunk; There is a roomy wardroom forward, where a game of gin rummy can be enjoyed. And we will have a fresh-water shower, washing and toilet facilities." Considerable intelligence has been devoted to life-support systems that are foolproof and use practically no electric power.
Cooking water stored near boiling
Food will be the freeze-dried variety, "cooked" by adding hot water; To avoid using power to heat it, the hot w-ator some 190 gallonsis carried in "superinsulated" tanks designed to keep it just below boiling for the whole month. The superinsulationa vacuum jacket surrounded by layers of aluminized mylar filmwas developed originally for the Apollo lunar spacecraft.
Another 380 gallons of water is aboard for drinking, washing and toilet-flushingover two gallons per man per day. Waste water cannot be pumped overboard. That would reduce the sub's weight and make it rise. So well-sealed waste tanks are provided.
Due to the long duration of the voyage, unusual attention had to be paid to control of odors and poisonous fumes from electrical and lab equipment as well as from humans. Forty different gas-detector tubes will identify contaminants in the atmosphere, and a catalytic burner will dispose of what activated charcoal won't remove. Breathing atmosphere is supplied by a surprisingly simple systemtwo standard industrial Thermos-bottle-type tanks of liquid oxygen, to be vaporized and metered automatically, plus trays of lithium hydroxide for carbon-dioxide removal.
Heating is not expected to be necessary. Since the surrounding water temperature will be about 61 °F., heat generated by machinery and crew will keep the cabin temperature between 63 and 81'.
Barring any emergency, the scientists should have ample opportunity to study the marine scene through the portholes. Unlike many research subs. the Franklin is not equipped with a claw for taking samples. It does have one unique sampling device, a quartz tube connecting twof the rear portholes. Equipped with valves, it permits small quantities of water to be brought inside the sub, where small marine life can be studied under the microscope at depth pressure. They can then be allowed to swim out or be added to the biologist's collection.
A form of marine life Piccard hopes to study, he said. is what is known to oceanographers as the "deep scattering layer". This shows up on sonar scopes as a false bottom at depths down to several thousand feet. The DSL is thought to consist of shrirnplike creatures or small fish; it moves up toward the surface at night presumably in response to darkness; Many attempts have been made to sample the organisms, with confusing results. Piccard
believes the Franklin is the ideal tool for study of the DSLit can spot the layer on sonar from below or above, place itself right in the layer, and follow the slow rise and fall of the layer through its 24-hour cycle.
The submarine is also ideally suited to study ocean sounds, since most of the time she will be drifting with motors and noise-making gear shut down. Tape recorders will capture the grunts, chirps and clicks that fish make, and the dull grating of the water over the sandy bottom. The sub will also study undcrwater sound transmission, a fascinating subject for the Navy.
If all goes well, the mission will be terminated when about 80 percent of battery power has been used. The Franklin should then be 100 to 250 miles off Cape Cod. The procedure for coming up, if nobody's in a rush, is the opposite of going down. Blow water out of the ballast tanks with compressed air.
Steel shot speeds surfacing
The sub also carries over six tons of steel shot that can be dumped to bring her to the surface in a hurry. The shot is held in two hoppers by electromagnetic "valves." A steel ring at the mouth of each hopper is permanently magnetized, so it takes no electric power to keep the shot in place: a pulse of current through a coil can demagnetize the ring and let the shot pour out. A second ring of soft iron can be variably magnetized to meter out shot if desired. A total power loss is the worst emergency that could occur, says Piccard. If that happened, the shot could be released through a hydraulic gate pumped by hand.
Piccard is confident no serious emergency will arise. It's certain that one exciting moment will be the end of the trip when the sub surfaces in the rough North Atlantic. The Ben Franklin will be heaving, rolling, and pitching as a small boat comes over from one of the escort ships. After the towline has been secured, Piccard and his companions will transfer to the small boat.
The sub and the boat are going up and down," says Piccard, demonstrating with his hands. " There comes a moment when the two are togetherthat's when you Jump.
gene carl feldman (firstname.lastname@example.org) (301) 286-9428