INTRODUCTION 
From 12-20 December, 1966, Robert DeLong and Patrick Gould 
conducted pelagic observations off the coast of Southern California. 
They vere guests of the U.S.S. Henderson (D.D. 785),and were 
present on a not to interfere" basis. Watches were maintained from 
sunrise through sunset for the entire trip. Periodic nocturnal 
checks were made, but the poor weather conditions, principally fog, 
and the fact that the ship was running under blackout conditions, 
prohibited any extensive nocturnal watches. Weather and locality 
data were provided by the ship's navigator. The officers and crew 
extended excellent, courteous and cheerful cooperation throughout 
the trip 
ITINERARY 
The ship left the Terminal Island Navy Base of Long Beach, 
California,at 1600 hours on the 12th of December and headed west- 
northwest to about 37°N by 123°W. It then turned east-southeast 
and moved into the area around 31°30'N by ll8°00"W where it remained 
on maneuvers until 19 December when it returned to Long Beach with 
a short stop at Seal Beach on the 20th (See TABLE i). The area 
of maneuvers will hereafter be referred to as the Grid (See FIGURE i). 
A total of 76.I hours and approximately 69^+ miles of diurnal 
and 2-5 hours and ^2+ miles of nocturnal observations was concluded 
(See TABLE II). Since mileage estimates are unreliable due to the 
1 
