ensured closer control of the ships and enabled them to be located closer together and
to experience similar fallout. After the shot, the unmanned radioactive ships were towed
back to Eniwetok Lagoon by the ATF-106, and decontamination was initiated subsequently.
6.2.1 Operational Results. The location of the ships during Shot 1 was determined by
lower-level, preshot wind forecasts. Changes in the wind structure and the unpredicted
oN
od ou
MESS
= Bex
Start: ani RSX
l
Step : H+ 12 Ae
Z
{
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Figure 6.2 Ship’s course, Shot 5.
height to which the radioactive material was carried caused the fallout to occur east of
Bikini Atoll, while the ships were west of Bikini. The resultant low contamination levels
denied the acquisition of useful data.
The ships were more-favorably located during
Shot 2, but a control failure caused the YAG-39 to stop before fallout ceased, and the two
ships did not experience comparable events. The results from Shots 4 and 5, during
which the YAG-39 was manned, were more satisfactory, with the highest doses being
experienced during Shot 5. Figure 6.2 presents the ship’s tracks during Shot 5, together
with a hodograph of the wind structure.
In spite of the close operation of the two ships during Shots 4 and 5, appreciable differences in fallout were observed: the dose that would have been observed aboard YAG-39,
had it not been washed down, varied (with time) between 25 and 100 percent higher than
that actually observed aboard YAG-40. Operation of a single ship with part of the deck
washed was recommended to eliminate this problem at future operations.
6.2.2 Washdown System Evaluation. The washdown system aboard the YAG-39 operated successfully at a rate of approximately 2,000 gal/min. The only difficulty was a
stoppage in the boat-deck drain during Shots 4 and 5, which impeded the removal of con-
taminated water from this area.
The coverage was adequate except when the wind was
81