Marine Hose must be specially designed (with proper formulations and flexible heavy wall construction) to provide the best possible, long term performance and resistance to its fluids and aging in a tough environment (vibration and movement, heat and cold, ozone, salt air & water).

Typically, raw water is pumped from the engine intake seacock and strainer; through a heat exchanger, possibly oil cooler(s) and water injection nipple or mixing elbow at the exhaust manifold; and itâs dumped with the exhaust gas (cooled from 1100° F. + to less than 212°F. on most engines) into the wet exhaust piping and out the stern. Most commonly the latter is a combination of flexible rubber exhaust hose, bellows & elbows; sometimes fiberglass or stainless steel pipe (at least for connectors); and mufflers or silencers. Flexible hose, bellows an elbows are easier and simpler to run than rigid pipe. They are not subject to corrosion or stress cracking; and they absorb more engine movement, vibration and noise. While the highest quality black rubber exhaust withstands maximum continuous temperatures up to 250°F., some high performance engines emit wet exhaust at 300° to 500°F. Here only silicone rubber can be used.