Complex sentence: Though given clearance to leave the port on 5 December, Imos departure was delayed as her 50 tons of coal did not arrive until late that afternoon and was not completed until after the anti-submarine nets were raised for the night.
Split into simpler sentences: Though given clearance to leave the port on 5 December, Imos departure was delayed as her 50 tons of coal did not arrive until late that afternoon. The loading of fuel was not completed until after the anti-submarine nets had been raised for the night.