Further recommendations. Whisper Power M-SC12, M-SQ25, M-SQ6, M-SQ16, M-SQ12, M-SC6, M-SQ8, M-SC3.5

2.1.5 Further recommendations

When it is not possible to drain the oil from the box cooler, one should pump out the engine sump as good as possible and increase the oil change intervals to every 50 running hours.

As the (indirect) cooling by outboard water is very efficient, keel cooling is without problems. Most important is to avoid air traps in the piping and additional ventilation of the pipes can be necessary when bents are not to be avoided

(refer to figure 7).

Figure 7: Ventilating an air trap

Using a box cooler the outboard water will bring the temperature of the engine coolant only 10 up to 15°

Celsius down. The difference between 90° “in” and 80°

“out” (ΔT) is hardly noticeable. So do not conclude too fast that the system is not working well. When using another system than the recommended box-coolers one has to be certain that the cooling capacity is enough. Paint and fouling on the hull or on pipes along the bottom can reduce the cooling capacity of the system.

2.2 DRY EXHAUST SYSTEM

A dry exhaust muffler system should be as effective in silencing the exhaust as a wet marine exhaust system when applying the right mufflers. However noise could be generated by vibrations in the mufflers and be transferred to the structure of the ship. Tacit factors like the length of specific pipe sections could be important. It is very difficult to take these factors into account.

A dry exhaust system on a boat can generate noise problems caused by resonance of the pipes and mufflers.

INSTALLATION

Figure 8: Dry exhaust system

The standard WhisperPower exhaust kit contains the materials to perform a professional installation. In the kit is a stainless steel flexible bellow (hose) to prevent vibrations to be transferred. Also rubbers are supplied to mount the mufflers flexible. The insulation blanket for the flexible bellow and the mufflers are also very effective in damping vibrations. Still it could be that additional measures has to be taken like an extra clamp in a vibrating section of pipe, insulation blankets on other parts of the system and possibly even additional mufflers.

Special care has to be given to avoid water from outside to get into the system. When the exhaust is led through the deck or through the roof of the wheelhouse, measures has to be taken to prevent rainwater to enter the system. Special rain caps are available as an option.

Figure 9. Ways to prevent water to get in

A negative feature of a dry exhaust system is the heat radiated by its components.

Measures are to be taken to overcome the heat problem:

The exhaust bent to bring the exhaust out of the canopy is cooled by water. Insulation blankets are included in the exhaust kit to insulate the flexible bellow and the mufflers.

When a dry exhaust has its outlet on the deck or the roof, all the pipes inside the ship that can be touched by people, has to be insulated.

EN / WhisperPower keel cooling / September 2010

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