Raymarine ST30 Round Bidata Owner's Handbook Manual page 21

Chapter 3: Installation
bidata
depth
speed
depth
89.1 mm (3.5 in)
94.15 mm (3.7 in)
CAUTION
Where it is necessary to cut holes (e.g. for cable routing and
instrument mounting), ensure that these will not cause a hazard by
weakening critical parts of the vessel's structure. If in doubt, seek
advice from a reputable boat builder.
1. If appropriate, use the template provided near the back of this book
to mark the intended location of the Bidata instrument.
2. Use a tank cutter to machine an 85 mm (3
the instrument.
Note: If you do not wish to use a tank cutter, the hole can be machined
using a hole saw and a file.
2. Remove any burrs from the aperture.
speed
17 mm
(0.67 in)
37.5 mm
(1.47 in)
54.5 mm (2.15 in)
3
/ in) clearance hole for
8
11
D1598-2
D1599-2