Keel-Cooled Engines for Workboats
Engines arranged for closed-circuit keel cooling and dry or partly dry exhaust, for tugs, dredgers and craft working in silty, weedy or debris-laden water.
Features
- No raw water passes through the engine, so blocked strainers and impeller failures stop being a daily risk.
- Cooler capacity is calculated from the heat to be rejected and the water temperature, and an undersized keel cooler cannot be corrected by anything on the engine.
- Marine growth on the cooler surfaces reduces capacity over a season, so cleaning appears on the docking list rather than the service schedule.
- Well suited to vessels that sit in shallow water or work close to a bank, where a raw-water intake picks up sand.
- Dry exhaust with insulated lagging is common, which changes the engine room heat load and the ventilation requirement.
Specifications
| Figure | Typical range | Unit | Why it matters |
|---|---|---|---|
| Heat to be rejected | as stated for the rating | kW | the figure the keel cooler is sized from |
| Design seawater temperature | 25 - 32 | degrees C | cooler sizing depends on the warmest expected water |
| Cooler surface area | as designed | m2 | cannot be increased once the hull is closed up |
| Exhaust arrangement | dry, lagged | drives engine room ventilation and heat load | |
| Engine room ventilation | as calculated | m3/h | a hot engine room de-rates the engine inside it |