The Submarine in War and Peace: Its Development and its Possibilities

by Simon Lake

CARGO-CARRYING SUBMARINES OF THE AUTHOR'S DESIGN

They will carry 7500 tons of cargo on a surface displacement of 11,500 tons; their submerged displacement is about 13,500 tons.

Convoys.—Convoying a merchant fleet offers perhaps some safety to the individuals on the ships in case some of them are lost, but I cannot see that it offers much protection to the fleet as a whole, as the speed of the fleet is limited to that of the slowest ship, and the smoke or appearance of the leading ships are more apt to give a waiting slow-speed submarine time to catch up with the tail end of the fleet. If it came to a gun fight the fleet might have the advantage, but in experimental work I have frequently run in amidst a fleet of ships, and their first knowledge of my presence was when the periscope was extended above the surface. As it is only necessary to extend this for a period of a few seconds' duration to get the range and bearing of one of the ships to aim the torpedo, the chance of a gunner getting the range and hitting the periscope is very slight, and, even if the periscope were destroyed, it is easy to replace it with a spare one.

Smoke Screens.—To hide vessels in clouds of smoke so as to avoid being seen by submarines has been proposed as a method for eluding the U-boats. This procedure would really assist submarine commanders in their search for prey, for the smoke would notify them of the presence of vessels far below the horizon, whose location and course they would otherwise not be aware of. They have a term in the British navy called "firing into the Brown," which means firing at a group of vessels, expecting that a certain percentage of hits will be made, depending on how close a formation of ships is being kept; firing into the "smoke" would be apt to get some. Smoke screens can be used effectively only when the wind happens to be proportionate to the speed of the ships and blowing in the right direction. With a head wind or a strong side wind some of the vessels forming the convoy are sure to be exposed to attack.

Zigzag.—Steering zigzag courses adds to the time of crossing from one port to another, and affords only a slight measure of additional safety, as a ship running a zigzag course takes much longer to make a crossing, and is therefore longer exposed to danger; besides, this process adds very materially to the cost of the voyage. It probably does add somewhat to her chances of escape, as a submarine lying in wait anticipating that she will pass within torpedo range might be fooled by her zigzagging out of the way. On the other hand, a submarine might be lying in wait too far to one side of her course to be able to intercept her, and the ship might just as likely as not, not knowing she was there, zigzag right toward her and get caught.

In facing the submarine problem, the nations at war with Germany are thus forced to adopt tactics of three kinds: First, to destroy the enemy submarines—I have been informed from reliable sources that England has over five thousand vessels searching for U-boats; second, to make cargo vessels invulnerable to torpedo attacks; and, thirdly, to elude and escape the U-boats. No great measure of success, no great results, have come out of attempts of the first two orders; the U-boats have in general gone unscathed, and they have inflicted damage of such an appalling nature as to terrify those cognizant of the shipping needs of Europe. In my judgment, however, efforts to combat the submarine should be concentrated on devising ways and means to elude it; this is the only solution which promises results. I shall therefore devote the remainder of this chapter to a discussion of the problem of eluding submarines and how it may best be accomplished.

Cargo Submarines.—In my judgment, the only way that any nation will be able ultimately to continue its commerce with any degree of safety or certainty when blockaded by submarines will be by the construction of large merchant submarines which will be able to evade the enemy U-boats successfully.

I have pointed out above that "submarines cannot fight submarines," because they cannot see or locate each other. It is this very thing which will enable the cargo-carrying submarine to evade the military submarine. They are also able to evade all surface craft, either friend or foe. Captain Paul Koenig, of the Deutschland, told me that most of his journey in the Deutschland was upon the surface. He stated that her low visibility enabled him to see all approaching ships before they could see her, and that it was only necessary for him to submerge and rest until the surface ship had passed on her way. The tactics of the larger cargo-carrying submarines would be the same. They need not have much radius of action when submerged; all they need to do is to hide until the danger has passed. If desired, however, their radius of submerged action may be increased to equal or largely exceed that of a military submarine, but this would unnecessarily increase their cost of construction; otherwise the cost of building such vessels should not exceed twenty-five per cent. more than the cost of constructing a first-class surface ship.