Hull Preparation; Fixing The Intake Block To Hull - Hamilton Jet HJ241 Manual

5 INSTALLATION
5.2 H P
ULL REPARATION

5.2 HULL PREPARATION

In Multi Jet Unit installations,
each Jet Unit may have been
configured for Port, Starboard or
Centre mounting. Care should be
C
AUTION
taken to ensure that each Jet is
fitted in its correct position.

5.2.1 Fixing the Intake Block to Hull

G.R.P. HULLS OR WOODEN HULLS:
Drawing HJ-241-08-001 Installation Details GRP
Hull.
If possible, tape the Intake Block into the hull mould
prior to moulding the hull. For centre-mounted jets
an additional smooth surface will have to be taped
to the mould in front of the Intake Block to mould
over and form a fairing between the vee hull form
and flat of Intake Block. For a Wooden hull, or 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, as
shown on the installation drawing.
After moulding, drill 22 x 9mm diameter holes at the
cast dimples in the bottom of the Intake Block up
through the Intake Block flange and Hull.
Countersink the holes to accept the 8mm
countersunk Screws [11]. Fit the countersunk
Screws [11], Flat Washers [6], Spring Washers [5]
and Nuts [4], using RTV Silicon Sealant, [7]
provided. Tighten to torque for M8 Nuts, refer to
Drawing 85113 Recommendations for Fastener Lock-
ing, Torques and Threading Lubrication Sht
Ensure that the contours between the hull and the
Intake Block, at front and rear, are smooth to within
1 mm.
ALUMINIUM HULLS:—Drawing
stallation Details Aluminium Hull.
Once fitted, the Intake Block becomes part of the
Hull and is not removed when servicing the Jet Unit.
To assist with the correct alignment of the Intake
Block to the Hull bottom, the centreline is marked
fore and aft on the Intake Block.
The Intake Block is welded into the Hull. The Intake
Block base is butt welded flush with the underside of
the hull bottom as shown in Drawing
002 Installation Details Aluminium Hull.
The protruding weld on the underside of the hull
must be as small as possible especially at the
5.2
1.
HJ-241-08-002 In-
HJ-241-08-
forward end. Use the weld procedure shown on
Drawing 85080 Aluminium Weld Procedure for
Hamilton Jet Installation or Repair.
Ensure that the contours between hull and Intake
Block, at front and rear, are smooth to within 1 mm.
FOR STEEL HULLS:
Refer to Installation Drawing
stallation Details Steel Hull Sht1 & 2.
ELECTRICAL ISOLATION :—The Intake Block, Jet
Unit and Transom Plate must be completely
electrically isolated from the rest of the Hull. This is
achieved by the use of gaskets, bushes and studs, as
shown on the Hull Installation Drawings.
INSTALLING THE INTAKE BLOCK:—A steel recess
must be built into the Hull to accept the Intake
Block, as shown on the Installation drawing.
NOTE: The prepared opening has sloping faces fore
and aft to match the Intake Block. Use the
following procedure to mount the Intake
Block.
1. Once the prepared recess in the Hull is
completed, trial fit the Intake Block in place using
3mm spacers instead of the Intake Block Gasket
[17].
2. With the Intake Block in place,
3. Drill 22 x 8.5 mm diameter holes at the cast
dimples in the bottom of the Intake block, up
through the Intake Block Flange and Hull.
4. Drill through the countersunk points on the
Intake Block from below, with an 8.5 mm dia
drill. After piercing the Intake Block, make a
small marking cut in the steel hull with the drill.
5. Remove the Intake Block and clean off all burrs.
6. Drill out the marked positions in the steel edges
of the prepared opening to 12 mm to accept the
Nylon Insulating Bushes [19]. Remove all burrs.
7. Fit the Insulating Bushes [19] and trim to the
correct length. Remove the Insulating Bushes
from the Intake
8. Liberally smear both sides of the Intake Block
Gasket [17] with RTV Sealant [7] and fit the
Intake Block Gasket onto the Intake Block.
NOTE: The Gasket is designed to fold down around
the edges of the Intake Block.
HJ-241 / HSRX
HJ-241-08-003 In-