WÄRTSILÄ WARTSILA 26, Product Manual

Page: 15 / 196

sailing, in particular if open propellers are applied. If the bollard pull curve significantly exceeds
the maximum overload limit, acceleration and manoeuvring response can be very slow. Nozzle
propellers are less problematic in this respect.
2.1.3 Dredgers
Mechanically driven dredging pumps typically require a capability to operate with full torque
down to 80% of nominal engine speed. This requirement results in significant de-rating of the
engine.
Fig 2-3 Operating field for Dredgers
2.2 Loading capacity
Controlled load increase is essential for highly supercharged diesel engines, because the
turbocharger needs time to accelerate before it can deliver the required amount of air. A slower
loading ramp than the maximum capability of the engine permits a more even temperature
distribution in engine components during transients.
The engine can be loaded immediately after start, provided that the engine is pre-heated to
a HT-water temperature of 60…70ºC, and the lubricating oil temperature is min. 40 ºC.
The ramp for normal loading applies to engines that have reached normal operating
temperature.
Wärtsilä 26 Product Guide - a9 - 7 September 2016 2-3
2. Operating Ranges Wärtsilä 26 Product Guide