The Birmingham age-herald., 1918-11-10
,Copssnaca from Page FourJ

4n6 ADONS IcHldIhS DAdolAdtS fitSC eA-
 effectiveness of escorted conveys. Tn
 convoy is a group of vessels in regula
 formation. steaming as close to each oth
 CT as safety will permit, and surround
 ed by a screen of anti-submarine yes
 sels, For the purpose of escorting etthel
 a battle fleet or a mercantile convoy th'
 destroyer is by far the most efficient
 vessel. The reason of this is that the destroyer can increase her speed from a cruising speed of, say, 15 knots, to 7; or 90 in a very short time. This enables her quickly to reach the position where the submarine has been seen to go down She carries 30 or 40 depth charges each with several hundred pounds of high eX- plosive. These are arranged so that they will explode after sinking to any re- ouired depth. The consequence is that it is a very dangerous thing for sub marine to approach a convoy that is es- corted by destroyers. If she hopes to destroy some of the merchant vessels she must approach close enough to have a reasonable chance of making a hit with the torpedo, and at this distance she runs a grave risk of being seen and at tackled with depth charges.
 Question EHow long can a submarine remain away from it's base? How large a supply of torpedoes does submarine carry?
 Answer-A submarine of the Deutsch- olo aC T1rpNiOnS- Iy, stated, remain away from its base three or four months. In order that submarine may submerge she fills cer- tain ballast tanks full of water so as to decrease her buoyancy. When a subma- rine starts out on a cruise against com merce. she has her ballast tanks filled with fuel oil. With this supply. in ad- lition to what is in her oil bunkers, she can remain out three or four months. A submarine of this type can carry 5t mines. She can substitute torpedoes for some of these mines
 The ordinary submarine has also very long radius of action, but the lirni- tation of the time she remains out is de- rermined by the number of .torpedoes she carries If the hunting is good and she fires her torpedoes away in a week or so. she must return to her base, as she is no longer dangerous to commerce. These smaller submarines frequently re- main out as long as a month. They car ry from 8 to F torpedoes. There are oth- CTS of still smaller class which carry or torpedoes and IS mines, Improved torpedoes.
 Question 5-Has the submarine, as dem onstrated in the present war, changed the principles of sea power as laid down by Admiral Mahan? Is the submarine, with other defenses, an invincible means of defensive sea power?
 Answer-This question has been an swered under question No. 3. The sub marine has not changed the principles ot sea power as laid down by Mahan, and this for the reasons given in the answer to No. 3, It is not an invincible means of defensive sea power, because it cannot operate within an area that is suffi- ciently patrolled by efficient surface craft. No matter how numerous the sub- marines, they cannot prevent a battle aeet going where it pleases, provided his battle fleet is accompanied by a sufficient number of efficient patro craft AS previously stated. the most efficient craft for this purpose is the powerful modern destroyer.
 Question 6--Do the submarines ever operate in groups?
 Answer-No. The reason is a very sim pie one, and that is that allied subma- rines are used to- hunt German subma- rines. The consequence is that if two operate together they would be in con- tinuous danger of torpedoing each other. It has been explained above that sub marine can always escape observation by . surface craft, because she sees the surface craft long before the surface craft sees her. This is not true as con- cerns an enemy submarine. because ii two submarines approach each other each has an equal chance of seeing the other first, and getting in the first shot. The submarine recognizes that it's most dan eerous opponent is an enemy subma- rine. A German submarine operating against commerce spends most of its time on the surface. She submerges only when necessary to escape observation or when necessary to make an attack. A submarine must come upon the surface in order to use her oil engines for charg- ing her storage batteries with which she propels herself when submerged. If she is chased by surface craft carrying depth charges she can only escape by steaming in various directions, and sometimes for a considerable distance, below the water. Safety. therefore, re- quires that she keep her storage bat teries always as fully charged as pos sible. Submarines of the allies when hunt ing for German submarines, remain sub merged during the whole of daylight. only putting their periscopes up for a few seconds at intervals. If they see German submarine on the surface they are sometimes able to maneuver so as to get within torpedo range and destroy her. Submarines are the most successful vessels in destroying enemy submarines. There are often reports in the papers on submarines operating in groups" It is more or less common for merchant vessels to report that they