Beta Marine Beta 14 Installation Manual page 26

HEAT EXCHANGER COOLING - WET EXHAUSTS
Three major problems that can easily occur when installing
a heat exchanger engine in a vessel which need to be
managed to ensure the engine is not subjected to any
possible 'hydraulic lock'. This occurs when water is allowed
to enter the combustion chamber and 'hydraulics' against
the rising piston with the consequences possibly being,
a bent con rod/s, an emulsified engine oil and/or a
damaged fuel pump.
• Seawater syphoning past worn impellers in the
seawater pump, flooding the exhaust system, and
back filling into the combustion chamber when the
engine is stopped.
• Seawater washing into the combustion chamber from
the exhaust system due to either a very shallow
exhaust run from the injection bend to the waterlock
silencer, or because the waterlock silencer is too small
to accept the total amount of cooling water in the
14 Standard Exhaust System
30 cm
Normal Sea
Water Level
exhaust hoses, or both. This can happen when the
vessel is sailing into a big sea and a surge is set up in
exhaust system as the vessel pitches - with the engine
switched off.
• Waves forcing water up the exhaust due a poorly
designed system with no 'gooseneck'. Small work
boats moored on exposed beaches are very vulnerable
to this as waves hit the stern before the boat can
swing into the wind on a rising tide.
If the engine is installed below the water line, the
potential for water entering the engine is considerably
increased. The important dimension that must be
measured is from the normal 'static' sea level to the point
at where the cooling water is injected into the exhaust
- this should be a minimum of 30 cms. If this can not be
achieved the following options must be taken. Please refer
to images 14, 15 & 16.
Waterlock Silencer
Rope Cutter
24
Gooseneck
40 cm
Propeller Clearance