Why use a water-injected "wet" exhaust system?
The following factors are of great importance:
1) Exhaust gas temperatures can reach very high levels. A diesel engine can easily produce an exhaust gas temperature of 600°C or more.
2) The speed with which sound can be transmitted through air is dependent on the temperature of the air. This applies to exhaust gases as well. The higher the exhaust temperature, the higher the speed of sound through the gas.
3) The sound level, i.e. the relative volume of sound as experienced by the human ear, is in turn dependent on the speed of sound. As the speed of sound transmission reduces, so the sound level will reduce proportionally.
What requirements must be fulfilled by a "wet" exhaust system? In its simplest form, a rubber hose, running from the engine directly to the transom of the boat, seems adequate enough. However, the following issues must also be taken into consideration:
• After the engine is stopped, the cooling water in the exhaust system must not be able to flow back into the engine.
• Water outside the boat must be prevented from entering the exhaust system and therefore the engine, through the transom connection.
In order to fulfil these requirements, VETUS offers a complete range of exhaust components made of synthetic materials, such as:
A waterlock which will collect the cooling water present in the system when the engine is stopped. In addition, a waterlock has great sound-deadening capabilities and acts as a very efficient muffler. All VETUS waterlocks are designed to function with a back pressure of not more than 0,1 bar, which is very low compared with other waterlocks on the market. The size of the waterlock is not only determined by the diameter of the exhaust hose, but also by the quantity of water that must be collected. Therefore, VETUS offers waterlocks with extra large capacity for systems with long exhaust runs.
A gooseneck which raises the exhaust hose above the waterline, so that water cannot backfill the exhaust system. After the engine is stopped, all cooling water in the exhaust hose will run to the lowest point of the system, which is where the waterlock should be situated. In order to limit the quantity of water, the gooseneck should be fitted as closely as possible behind the waterlock. But, if required, it may also be fitted directly onto the transom exhaust connection. A transom exhaust connection which should be fitted above the waterline, as a general rule.
We recommend VETUS rubber exhaust hose for all water-injected exhaust systems: VETUS exhaust hose is extremely flexible but it cannot collapse when subjected to heat and is resistant to exhaust gases, temperatures up to 100°C, and oil residues. These hoses are Lloyd's approved and satisfy the SAE J2006 R2 directives. Always fit an exhaust temperaturealarm order to warn of excessive temperature in the exhaust system. This can happen if the cooling w ater flow is restricted or blocked altogether. VETUS marine diesel engines have an exhaust temperature alarm fitted as standard.
Why VETUS exhaust systems?
All VETUS exhaust systems meet the high standards our customers expect, with just some of the benefits highlighted below: • All VETUS exhaust systems meet required ABYC standards • Many systems come complete with rotating connections and bodies for easy installation of hoses from any angle • Excellent noise reduction is combined with minimal back pressure • Some available systems use a combination of gooseneck/muffler and waterlock/muffler • Our ASD air vent is the only one on the market with virtually no maintenance required • The ASD air vent can be easily dismantled by hand for cleaning • All materials are fully corrosion resistant • VETUS HD waterlocks offer better temperature resistance than GRP • Exhaust hoses are extremely flexible, making installation quick and easy