Complex sentence: In 1798 Captain Peter Halkett was appointed to the command of "Apollo"; on 7 January 1799 she was wrecked on the Haak Sands, off the coast of Holland, whilst chasing a Dutch vessel.
Split into simpler sentences: In 1798 Captain Peter Halkett was appointed to the command of "Apollo". On 7 January 1799 "Apollo" was wrecked on the Haak Sands, off the coast of Holland, whilst chasing a Dutch vessel.