Sailing SV Delos · video

What this video covers

Fabricating a custom marine diesel exhaust system for an aluminum catamaran requires balancing engine back pressure with the risk of seawater backflow.3:19 The system design incorporates a mixing elbow where seawater cools exhaust gases, a water lock to prevent water from entering the engine upon shutdown, and a gooseneck to create a high point that prevents seawater ingress during heeling or wave action.3:01 When installing the hull exit, the builder uses a 102-millimeter aluminum pipe fitted with a vinyl ester glass-reinforced plastic (GRP) tube, secured with Chokfast epoxy resin to ensure a watertight, vibration-resistant bond.7:04 Selecting a water lock, such as the Vetus NLP model, requires matching the inlet diameter to the mixing elbow and ensuring the unit has sufficient internal capacity to contain all downstream water.14:44 Proper exhaust routing demands a continuous downward slope to the water lock to avoid flow restrictions.20:40 Consulting with engine manufacturers helps determine the optimal gooseneck height to maintain safety margins above the waterline.22:34

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