Vessel Speed And Handling Trials; After Initial Trials (After Engine Shutdown) - Hamilton Jet HJ212 Installation And Service Manual

Installation and Service Manual

Vessel Speed and Handling Trials

A Hamilton distributor should be present to observe, record and verify results.
If a problem is detected, immediately return at reduced power, to the mooring. DO NOT
operate the jet unit until the fault has been repaired.
Leave the mooring and check that the steering is working correctly at Forward, Zero Speed and Astern.
When the vessel is moving dead ahead at speed, the waterjet coming from the steering nozzles should be
relatively clean with an even shape.
Check the jet unit and driveshafts are running smoothly (no vibration) over the entire engine operating speed
range (i.e. from idle to full ahead).
Regularly check and record the surface temperature of the bearing housing.
Due to friction caused by the seals, the bearing housing will be warm.

Bearing operating temperature should not exceed 80º C.

A faulty bearing can be heard and felt as vibration through the bearing housing and is likely to cause

significant heat build-up.
If possible, check the coupling joint temperatures. Increased joint temperature may indicate driveshaft
misalignment.
Regularly check and record the hydraulic oil temperature at the JHPU oil reservoir:
After an extended run at cruising speed.

After a period of vessel manoeuvring.

Record maximum speed using GPS and engine revolutions.
Strong currents will result in inaccurate speed readings since the GPS only provides "speed
over ground covered" readings.
At maximum speed the jet unit revolutions should be verified with a hand held tachometer at the jet unit
coupling.
If possible, record vessel speed at varying engine revolutions.
Record vessel trim, loading etc.

After Initial Trials (After Engine Shutdown)

Do any after trial maintenance that may be required. Refer to section: HJ Jet Unit Service Intervals on

page 8-9.
Make sure that all important information recorded during trials is stored for later reference.

Check for water leaks around the jet unit especially at the transom seal at the intake block and under the

bearing housing (water seal leaks).
For steel hulls, make sure the insulation resistance between the jet unit and the vessel hull is greater

than 1000 Ohms.
6-3
Commissioning