Vetus Waterlock NLP3 — Installation Manual

Before You Install

• VETUS exhaust components are for water-injected exhaust systems; maximum continuous operating temperature of the plastic components 70 degrees C (158 degrees F).
• Fit a temperature alarm to warn of excessively hot exhaust system temperature.
• If you reduce injected cooling water to lower back-pressure, check there is still enough water at tick-over. A near-vertical injection bend mixes well; a near-horizontal one at tick-over mixes poorly – a water vortex or splitter in the exhaust pipe can help.
• Exhaust hose must be reinforced and resist exhaust gas, high temperature (100 degrees C, 212 degrees F) and oil, flexible yet not collapse when hot.

Water entering the engine from the silencer or waterlock (e.g. under sail when the boat rolls or pitches heavily) causes irreparable damage. Too much water in it, also after repeated failed starts, can affect engine starting: drain it first.

Hose Size by Engine Power

* Based on an allowed back pressure of 0.1 bar.

Waterlock NLP3

• Preferably horizontal, but the OUT and IN sides must always be at least 5 cm below the exhaust injection elbow.
• With too little room behind the engine, place it ‘back-to-front’ alongside the engine.
• It gets much heavier with water in it: secure it with the ty-raps® supplied, through the slots in the housing.
• Under all sailing conditions (also heeled) the IN connection must be below the exhaust injection bend and the highest point of the waterlock at least 5 cm (2") below the bottom of the engine cooling water outlet.
• Both hose connections turn 360 degrees: loosen the bolts first, tighten to 1 Nm (0. 74 ft-lb, 142 oz-in).
• The parts of the housing can also be rotated relative to each other. The OUT part and both inner parts must sit as shown in the illustration (max. 30° either side); the IN part may be in any position. Never swap IN and OUT.
• To rotate: unscrew the clamp, turn the part, re-tighten the clamp to 0. 3 Nm (0. 22 ft-lb, 42 oz-in).

Exhaust Pipe and Transom

• Transom exhaust connection outlet at least 5 cm (2") above the waterline with the boat fully laden.
• Pipe slopes down over its whole length from the injection point to the waterlock; support it.
• Highest point not more than 150 cm (5 ft) above the underside of the waterlock; waterlock to highest point not more than 300 cm (10 ft).
• Fit hoses with only water and/or soap, NOT grease or oil; 2 stainless steel 12 mm (1/2") wide hose clamps per connection.
• A temperature alarm sensor can be fitted in the exhaust pipe.
• Syphoning: if ‘C’ is below or less than 15 cm (6") above the waterline (also when heeled), fit an air vent with air vent pipe or an air vent with valve between engine block and ‘C’. The air vent pipe can go to its own hull outlet (H) or to the connection on an NLPG goose neck (G).

Models and Volume

VETUS Rubber Exhaust Hose