Wet exhaust systems have decided advantages over dry exhaust systems. They are
quieter, cleaner and cooler; and do not pose a fire or burn hazard (eliminating
the need for insulation beyond the water injection point). Today, most pleasure
boats with inboard engines (for power, auxiliary, generator) have wet exhaust
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.
131V Ultimate Silicone Heater Hose- Very Hi Temp Blue
with Red Tube provides much greater temperature range and service life (up to 6
times longer) than standard EDPM rubber #130 Heater Hose. Both are 2 spiral
polyester reinforced with similiar working pressure for engine coolant water,
A/C and other mid-pressure water applications. #131V (VHT-Blue): 45 to
75PSI (0.31 to 0.52Mpa) WP 350°F (177°C) SAE J20R3, Class 1 & J20P3. 7 Year
#130 (Standard Black): 50PSI (0.34Mpa) WP 212°F (100°C) SAE J20R3. 2 Year
1/4" to 1"
6.3 to 25mm
1/2" to 3/4"
13 to 19mm
Blue Cover w/ Red Tube
Black w/ Yellow Letters
300' (90m) to 175' (53m) Coils
50' (15m) to 25' (7.6m) Boxes
500' (150m) - 450' (140m) Reels
50' (15m) Boxed