UNITED STATES PACIFIC FLEET
COMMANDER CRUISER
DIVISION THIRTEEN
HEXAGON SCREENING PLAN
1. For the maximum protection of a damaged ship proceeding at slow speeds and subject to enemy air or submarine attack, a circular screen of some sort is indicated.
2. With speed of advance of under ten knots, close screening by combatant ships in fixed positions introduces a heavy risk to the screen from enemy attack. Individual or coordinated zigzagging is possible only if some sacrifice of the completeness of the screen, and the closeness thereof to the screened unit, is acceptable.
3. With damaged ships deep in enemy waters, such compromises are not acceptable. Accordingly the following "Hexagon Screening Plan" is set forth. The general principle involved is the establishment of an acceptable method for the screening ships to continuously circle the screened unit, each ship employing the same relative track, thus maintaining her proper position.
4. Essential elements.
Base course and speed of screened unit. Base course is axis for the disposition. (A base speed of over 10 knots will not permit effective use of this plan, nor will it require this type screen.)
Screening Circle, in terms of 1000-yard circle spacing. This is the circle to which the hexagonal relative track is externally tangent. Choice of circle depends on number of screening ships, size of screened unit, and the danger of enemy air or submarine attack.
Relative Speed to be made good by ships of screen. For the screen to remain evenly distributed each leg must be covered in the same period of time by each ship. This requires a specific relative speed to be made good while traveling the periphery.
5. By use of a single signal, this plan may be put into effect. It will generally be well for ships to take fixed stations on the prescribed track, as prescribed by the OTC, before actuating the plan.
6. For ordering this screen, it is suggested that the following type of signal be used.
"FORM TYPE OF SCREEN INDICATED"
"SPECIAL"
"HOW" (for "hexagonal")
"8" (circle of tangency)
"030" (screened unit's course).
"05" (speed of advance)
"12.5" (relative speed to be used)
A time signal could be appended to set a time to commence the rotation of units about the screen track, if initial assignment were made to fixed stations on the track.
7. At night, or during low visibility, in order for the other ships to maintain station in this screen, it has been found helpful for the guide screening ship to announce her position when crossing ahead and astern. Such transmissions as "(cod name) ahead" and "(code name) astern", on the maneuvering circuit, identify the guide as the ship 000° or 180° relative from the base unit. This information permits identification of the guide on radar screens, and adjustments of speed and course as necessary by the several screening ships.
