Complex sentence: The cargo was put to use in the supply and defence of the Tromsø area, exempt the hay, which was quarantined by the Norwegian authorities at Ringvassøy for fear of foot-and-mouth disease.
Split into simpler sentences: The cargo was put to use in the supply and defence of the Tromsø area. The hay on board was quarantined by the Norwegian authorities at Ringvassøy for fear of foot-and-mouth disease.