How to Inspect and Maintain Your Boat’s Wet Exhaust Hose

The wet exhaust hose on your boat carries a mixture of hot exhaust gases and cooling water from the riser to the transom. It’s a critical safety component — and one of the first to suffer if your raw water system has a problem. If it overheats, cracks, or softens, you could be dealing with carbon monoxide leaks, melted insulation, or worse. Inspecting it regularly is easy and saves you from expensive repairs or dangerous failures.

What Is a Wet Exhaust Hose?

Unlike dry systems used in cars, boat exhaust is cooled by seawater injected at the riser. This mixture flows through a thick, reinforced rubber hose out the back of the boat. These hoses are usually marine-rated, wire-reinforced, and built to handle heat and vibration — but they aren’t immune to wear, especially if the cooling water flow is disrupted.

Where Problems Usually Start

Right after the riser elbow: This area gets the hottest and is most vulnerable if water injection is interrupted.
Bends or tight corners: Repeated flexing or improper routing can weaken the inner layers.
Where clamps are over-tightened: Excess pressure can crush the hose or cut into the outer wall.
Sections exposed to UV or bilge chemicals: Environmental exposure accelerates aging.

How to Inspect Your Wet Exhaust Hose

Let the engine cool completely before inspection.
Visually check the full length of the hose for cracks, blistering, or discoloration.
Feel for soft spots or areas that are unusually flexible — they may indicate internal delamination.
Tap or squeeze the hose near the riser — if it sounds hollow or feels mushy, it’s likely damaged.
Look for staining, soot, or water at hose joints — this could signal leaks from failed hose ends or loose clamps.

Signs the Hose Needs Replacement

Bulging, softening, or blistering near the riser
Cracks or surface splitting along any part of the hose
Soot or water stains around the hose ends
Sections that are flattened or collapsing under suction
Foul or burning rubber smell in the engine compartment

Best Practices for Maintenance

Inspect the hose at least once per season — more often in saltwater use
Flush the raw water system regularly to remove sand or debris that could reduce cooling flow
Use only marine-rated, wire-reinforced wet exhaust hose for replacements
Install new stainless steel clamps and torque them evenly
Check riser and elbow for blockage — many hose failures are caused upstream

Conclusion

Wet exhaust hose failure usually starts with heat — and it doesn’t give much warning. If cooling flow is lost for even a minute, the hose can soften or melt, risking carbon monoxide leaks, fire, or flooding. A simple squeeze test and visual inspection can catch the problem early. Don’t wait for smoke. Replace suspect hoses with marine-grade parts and inspect them like your safety depends on it — because it does.