Capt. DeWhitt Blamer, Commanding Officer, Seattle, to Rear Admiral Albert Gleaves, Commander, Cruiser and Transport Force
U. S. S. Seattle
SECRET 8 August 1918.
From: Commanding Officer.
To: Commander Cruiser & Transport Force.
SUBJECT: Letter of the Commanding Officer ORIZABA on subject of usefulness of zig-zagging.
1. I am strongly opposed to any support of an argument which would advocate the abandonment of zig-zagging as a protection against submarine torpedo attack.
2. Unquestionably zig-zagging has the dis-advantage of reducing by a small proportion the effective speed of a vessel, thereby increasing the danger area (ahead) within which an attack is made possible for an enemy submarine sighting his prey. But this increase of angle can in no way make up for the embarrassment and tactical difficulties placed in the way of a successful attack as the vessel approaches the submarine, by reason of the uncertainty of course of the zig-zagging vessel. The submarine must have a good approximation of the course and speed of his enemy and this too is made much more difficult for him.
3. It is well known that the submarine is so hampered in gaining an advantageous position for launching an attack, that zig-zagging will so handicap him that instead of being reasonably certain of turning up at his range of 1000 yards or so attention must be had, that such an error is not made as to involve the risk of collision. Particularly this is so when vessels are in convoy.
4. It would appear on the face of the matter without going into an analysis of the multitude of situations which present themselves by reason of the various forms of zig-zags and the many bearings on which a vessel may be sighted, that if one places himself in the place of the submarine with its large turning circle and loss of time in turning, that there is no comparison in the difficulties presented for making an exact contact between the system of a steady course and the zig-zag.
Source Note: TL, DNA, RG 45, Entry 520.