Hull Preparation; Fixing The Intake Block To The Hull; Transom Preparation - Hamilton Jet HJ212 Installation And Service Manual

Installation

Hull Preparation

In multiple jet installations, the jet units may be configured for either port, starboard
or centre mounting. Make sure that each jet is installed in the correct position as
shown on the installation drawing.

Fixing the Intake Block to the Hull

For GRP hulls
If possible, the intake block should be mounted in the hull mould before moulding.
For centre-mounted jets a smooth triangular surface must be provided in front of the jet unit to form a
fairing between the vee of the hull and the flat of the intake block
For an existing GRP hull, cut a hole in the hull larger than the intake block base flange to allow a scarfed joint
in GRP between the intake block and the hull, refer to the installation drawing.
To assist with the correct alignment of the intake block, the centreline is marked fore and aft.
The fixing of the intake block, the cross members to the hull, and the strength of the transom must be
sufficient to carry the loads imposed by the jet unit on the hull.
After moulding the intake block into the hull, drill 22 x 8.5mm diameter holes at the dimples in the bottom of
the intake block up through the intake block flange and hull. Countersink the holes to accept M8 countersunk
bolts.
Smear the screw holes and bolts [11] with marine sealant [7] then fit the countersunk bolts [11], flat washers
[6], spring washers [5] and nuts [4].
Tighten nuts to the specified torque. Refer to section: Tightening Torques on page 10-28.
Make sure that the contours between the hull and the intake block, at the front and rear, are smooth to
within 1mm.
For aluminium hulls
To assist with the correct alignment of the intake block, the centreline is marked fore and aft.
The intake block is butt welded flush with the underside of the hull bottom as shown in the installation
drawing. The protruding weld on the underside of the hull must be as small as possible especially at the
forward end. Refer to section: Aluminium Weld Procedure on page 10-26.
Make sure that the contours between the hull and the intake block, at the front and rear, are smooth to
within 1mm.
The fixing of the intake block, the cross members to the hull, and the strength of the transom must be
sufficient to carry the loads imposed by the jet unit on the hull.

Transom Preparation

For GRP hulls
An area at 95º to the jet intake base has to be prepared as shown on the installation drawing.
An insert can be placed into the hull mould so the required area at 95º can be moulded with the hull.
Alternatively the area to be at 95º can be cut from the transom and re-fibre glassed back at the correct
angle. To locate the cut-out transom area at the correct angle, install the jet unit, bolt the transom plate
assembly and transom cutout into position on the jet unit then fibreglass the cutout back to the transom.
For aluminium hulls
An area at 95º to the jet intake base has to be prepared as shown on the installation drawing.
Cut out the required area, reposition at 95º and re-weld (with required inserts at sides and top) back to the
transom.
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Installation and Service Manual