Lieutenant Commander Sloan Danenhower Outlines How He Will Navigate Craft To Safeguard Expedition: Describes Inventions To Nullify Dangers in water Beneath North Pole.

What perils may lurk before Captain Sir Hubert Wilkins, our comrades and myself in the icy water we are to explore can only be conjectured. One thing is certain, however: The most elaborate precautions are now being taken to assure our safety and to enable our scientists to carry out their extensive program of research successfully.

Our submarine is being equipped as no submarine before - with a perfect host of safety devices, many of which were designed especially to nullify various hazards we are likely to encounter.

In this article and a second, to appear in an earlier issue, I will outline the unusual undersea dangers with which I expect to be confronted as master of out vessel and explain in detail the many ingenious devices provided to assist us in surmounting them.

The Nautilus is a twin screw vessel and is powered by two 500-break horsepower, four-cycle vertical-trunk-piston, air-injection Busch-Sulzer-Diesel engines connected to two 200-horsepower Diehl electric motors.

The two oil burning Diesels will be used for motive power when the craft is operated on the surface; the electric motors will be our pushers when we are submerged.

The motors obtain current from a 120 cell Excide storage battery, type WL-43, which weigh more than 60 tons and has a total capacity of 5,000 amperes.

To get a mental picture of the Nautilus, imagine a steel cigar 175 feet long, with a flattened top side. This "cigar" is 15 feet 9 inches across at its widest point, and is 18 feet 3/8 inch high from the keel to superstructure at the center, not counting the additional height of the conning tower.

All the semi-circular frames or "ribs" of the submarine, spaced about 18 inches apart from bow to stern, are tangent to a single top line instead of being symmetrical about a central axis like the hoops of a barrel.

The superstructure rises above the top and serves as a working platform while the vessel is on the surface. It fills with water automatically as the vessel submerges, and empties through sluice ways as it rises.

Arching above the superstructure, running from end to end of the vessel and protecting the conning tower is a "sled deck", the first major indication that the submarine you are visualizing is no ordinary underwater boat. This deck is designed to serve as a sled on the bottom and to enable us to slip along on the under side of the ice when necessary, smoothly and without damage to our top hamper.

Inside the vessel, starting with the bow, we find still more indications that the Nautilus is far from being an ordinary submarine.

As the USS O-12, the vessel had four torpedo tubes. When we came to recondition her for the Arctic service, we at first considered utilizing these tubes for powerful bow lights. However, the boat was to operate under ice. She might on occasion, smash head-on into some huge submerged ice cake, rock or other obstruction. If we left her with a flimsy nose it could be crumpled at the first impact, icy water could flood in upon us and down we would go unless we could slam our watertight compartment doors quickly enough to confine the water to a section or two.

We decided not to take a chance. We discarded the idea of the lights and gave the Nautilus a "hard nose" made by blocking the torpedo muzzles with heavy steel plates and packing the bow tip solid with concrete.

The compartment into which the breeches of the torpedo tubes project is the old torpedo room. This we converted into a diving compartment, air lock and laboratory. through the diving compartment our divers can emerge into the water outside the boat to make any necessary exterior repairs or to conduct scientific experiments.

Underfoot here are the tanks, in which are stored the fuel oil for the big Diesels, distilled water (in a lead lined tank) for re-watering the storage battery, and a supply of fresh water for the members of the expedition.

Next, toward the stern is the old magazine, rearranged to house the base of a new telescopic conning tower which we have provided. Here also is installed the echo sounding equipment for measuring the oceans depths.

Between this compartment and the next is a water tight bulkhead. Then comes the forward battery compartment. Under our feet her are stored sixty of our 120 Excide battery cells, each weighing more than half a ton. The compartment itself is fitted up as comfortable living quarters for the men who will make this strangest of strange cruises.

There will be vents at the top through which the warmer air will rise and pass into the space between the hull and inner lining. The moisture in the warm air will be deposited against our inner "skin" and drop down to the bilges, whence it will be pumped overboard.

This insulation is very important because by it we maintain habitable living quarters, dry and fairly warm.

Continuing aft through another water tight bulkhead we enter the central control compartment --the "C O C" as we call it.

Here is the brain of our vessel, corresponding to the pilothouse of a surface ship. A maze of valves, gauges, wheels and recording instruments, this little room may hold in a large measure the fate of our expedition.

A wrong move here, the misreading of a gauge, the twisting of the wrong wheel, the overlooking of a single vital instrument --and we might plunge down into the blackness of the Arctic depths, our lives snuffed out and the secret of our end an everlasting riddle.

 Here in this control room is my station. Here "going it blind", as one always does in any submarine, with only instruments tested in other and infinitely less dangerous water to guide us, we will seek to steer our vessel safely to our destination.

The air control manifold, depth gauges, horizontal and vertical steering gear -- by which a submarine is guided right or left or up or down -- gyro and magnetic compasses, periscope and similar devices are in this "C O C".

Next toward the stern is the after battery compartment and galley, with the battery cells underfoot here as in the forward section. The galley is equipped with an electric range, electric vacuum cooker and electric ice box.

The engine room is next. Here are the main switch board and the two great Diesels. Space is at a premium here but there is room to get behind the engines to make repair them if necessary.

The motor room is next, and contains the electric motors, a lathe, drill press, grinder and other equipment to facilitate making repairs at sea.

The method of operation of the nautilus is conventional for a submarine of her type. Sea water is admitted to her ballast tanks to destroy her buoyancy and cause her to submerge.  This water is either blown by compressed air or pumped from the ballast tanks to restore her buoyancy and cause her to rise.

Contrary to popular belief, there is a normally little or no rise of atmospheric pressure inside the submarine.  The barometer is watched carefully and when any considerable rise is occurs the excess air is discharged overboard, reducing the pressure inside the boat to normal. 

Sufficient air is contained in the storage flasks to permit the crew of eighteen to live for about three days submerged. By the use of soda lime to remove the carbonic acid gas, and oxygen to regenerate the air, it is expected to increase the possible living time to six days.

The Nautilus, operating on the surface and using her Diesel engines at the economical surface speed of 10.99 knots and hour, has a maximum cruising radius of 7,326 miles.

When submerges the electric motors turn the propellers and the speed, of course, depends on the rate of discharge of the battery. With this discharge at a rate which will give the Nautilus a speed of three knots submerged, the vessel can run for slightly more than 40 hours, so that her maximum underwater radius on one battery charge is about 125 miles.

When it is desired to recharge the battery, the boat comes to the surface. Throwing out the clutches os the propeller do not operate, we start the Diesel engines and the electric motors connected to them then become generators, putting current back into the storage battery.  When the battery again is fully charged we can run another 125 miles at three knots submerged.

Under the ice I do not propose to run the Nautilus faster than three knots ordinarily, because at that speed - just about a walk - we could strike an obstruction without serious damage to out vessel. Her "hard nose" and special collapsible bowsprit are designed to withstand the shock of a collision at this slow speed.

Normally, it takes eight hours in the air to charge the storage battery. We propose to spend not more than sixteen hours out of each tweny-four submerged. The other eight hours will be devoted to charging the battery and taking various meteorological observations.

If we can make 50 miles toward our destination each day, it will permit us to make the voyage of 2,100 miles from Spitzbergen to Behring Strait via the North Pole in about forty two days. Starting July 1 from Spitzbergen we should arrive at Alaska about the middle of August, before the freezing recommences.

The problem is to find open spaces in the polar pack ice available and coinciding with our daily necessity for coming up to charge the battery.

A submarine with an enormous storage battery giving her an underwater cruising radius of, say, 600 miles would find it no trick ay all to submerge to 100 feet at the edge of the polar ice and proceed, if no obstructions were encountered, direct to the North Pole.

Should we fail over any extended period to get air, even by using our emergency drills and dynamite, our batteries would lie dead and useless, we could not move, we could not breathe, we shd die.

In that event we might float for years derelict against the underside of the Arctic pack. Or bob up too late to do us any good - like some monster of the deep and wallow in some fridgid polar lead wit honly the startled eyes of polar bears and guillemots and auks to see us.

The bouyancy of our submarine would float us on interminably.

We might even drift, years later, through somevagary of some arctic current, down into a temperate ocean, to bump and scrape along the hull of some liner. And be taken in tow and brought again into our home port - a skeleton crew whose records had out lived it - to revive the dramatic story of our striving as the discovery of Andree's camp so recently revived his long-forgotten exploit.

Not a nice picture! I don't like it myself, but the possibility is there.

The Nautilus has been tested at a depth of 223 feet, but during our builders' trials we will test her again to at least 200 feet.

A landsman might be surprised that we are gong to first try the boat in fresh water, but sucj fresh water trials are important.

This is why:

In the Polar Sea in summer, there are large areas where surface water is fresh, a layer of fresh from the melting ice on top of the salt.

A vessel sinks more readily than in salt.  In fresh water the  Nautilus will not have to take in so much water to cause her to submerge before her ballast tanks are full, which might cause a condition of "free" water in the tanks, affecting her stability and causing her to plunge.

The bottom is a long way down up there - 1600 fathoms - and we don't want to smack it.