Site preparation
2-7
2.2.5 Ship motion and offset from the ship’s motion centre
Even though it is recommended to mount the ADU high, keep the distance between the
ADU and the ship’s motion centre as short as possible. The higher up the ADU is
mounted, the higher is the linear g force applied to the ADU. The g force also depends on
the roll period of the ship, see Table 2-1. If the g force applied is too high, performance
and ADU signal stabilization may be reduced and eventually the ADU may be damaged.
Refer to the following table for allowed mounting heights above the ship’s motion centre.
Figure 2-5: Maximum distance from the ship’s motion centre (h max)
Min.
roll period
Max. ADU mounting height (h max)
Full
performance
Potential risk of damage
4s 12m 16m
6s 27m 35m
8s 48m 62m
10 s 75 m 98 m
Table 2-1: Maximum distance from the ship’s motion center versus
ship’s roll period