Raymarine Autohelm ST7000 Installation Instructions Manual page 22

The drive unit is mounted by bolting to a
substantial frame member (Fig. 16).
mounting foot is secured to the drive unit by four
equally spaced caphead screws and may be
rotated through 90 deg.
convenient mounting position if required (Fig. 17).
In some cases, it may be necessary to fabricate a
special frame to mount the drive unit., It should be
noted that chain tension can exceed 230Kgs
(500lbs) and thus an extremely rigid mounting
structure is vital to maintain good chain alignment.
Installation failures can occur in this area and it is
desirable to 'over engineer' the drive unit
mounting. All fastenings should be secured by
lock washers.
Provision must also be made for chain adjustment
which is most easily achieved by removable
shims placed under the mounting foot or by
elongated clearance holes in the mounting frame
as illustrated in Figs. 16 and 17.
The
to provide a more
17