Site preparation
3-10
Chapter 3: Installation
98-148248-A
Mast length and diameter
The placement of the ADU must ensure a rigid structural connection to the hull or structure
of the ship. Parts of the ship with heavy resonant vibrations are not suitable places for the
ADU. A small platform or short mast shall provide rigid support for the ADU fastening bolts
and a rigid interface to the ship.
If it is necessary to use a tall mast, you must stabilise the mast with bracing. The cross-
sectional properties and the corresponding maximum free length give a natural frequency
close to 30 Hz. Shorten the mast length as much as possible to obtain higher frequencies.
Preferably, mount stays or wires to stabilize the mast further.
Figure 3-10: Free mast length and example bracing for a tall mast
Note
Make sure that there is free space below the drain tube. See also
Note
Bracing and rigid masts can still not prevent vertical vibration if the mast is
attached to a deck plate that is not rigid. Make every effort to mount the mast on
a surface that is well supported by ribs. If this is not possible, provide extra deck
plate propping.
Free
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SAILOR600Ka-IM-98-148248.book Page 10 Monday, November 23, 2015 1:36 PM
