| Marine exhausts systems are an important and often | | | | layout of the engine room, is to prevent hydraulicing |
| overlooked part of a marine engine. Most vessels | | | | of the engine. This is caused when an engine has |
| have a 'wet' exhaust system. Salt water is injected | | | | filled with salt water which has entered via the |
| at the riser - the outlet for exhaust from the | | | | exhaust and can cause extensive damage if left for |
| exhaust manifold. This mixture of exhaust gas and | | | | more than two hours. Water enters the exhaust |
| water is then passed through a series of bends until | | | | from wave action at stern and poor exhaust design. |
| it exits the boat, preferably at the stern. | | | | In some ocean conditions, such as a following sea, |
| Exhaust gases mixed with salt water create a highly | | | | water can be forced back up the exhaust when the |
| corrosive compound. This is why exhaust systems | | | | engine is not running. Poorly designed exhausts allow |
| are commonly made using non-corrosive components | | | | water to flow back and fill the waterlock/muffler box |
| such as nitrile rubber reinforced hose (brown - not | | | | then up the hose into the exhaust manifold, through |
| green - stripe), galvanized steel, fiberglass or plastic. | | | | the exhaust valves and into the combustion chamber. |
| The purpose of these components, which vary in | | | | With the engine full of water the engine cannot crank |
| size and shape depending on the engine size and | | | | over as it is cannot compress water. |