The most common type of exhaust – and safest in terms of fire risk – is the wet exhaust, where cooling water is injected into the pipe at the manifold But beware backflow into the engine.
The conventional wet exhaust is a purpose-made flexible reinforced rubber tube connected to the exhaust manifold on the engine and usually terminating at the transom. The cooling water from the engine or heat exchanger is injected into the exhaust manifold outlet, cooling the exhaust pipe, before exiting along with the exhaust gases.
cooled systems. The raw water used to cool the fresh water in systems with heat exchangers, such as this one, is also exhausted with the gases.
A Vetus exhaust system in place on a mocked-up boat, showing clearly the swan neck (or goose neck) in the foreground, muffler and waterlock or trap.
Having water in the exhaust can lead to backflow into the engine, with consequent damage.
Safeguards include an antisyphon device, a water trap and a swan or goose neck.
