Complex sentence: She was built in 1806 and is best known for the 1825--1828 Captain Beechey expedition to the Pacific Ocean, primarily and explored as far north as Point Barrow, Alaska, the furthest point into the Arctic any non-Inuit had been at the time.
Split into simpler sentences: She was built in 1806 and is best known for the 1825--1828 expedition under Captain Beechey to the Pacific Ocean. She explored as far north as Point Barrow, Alaska, the furthest point into the Arctic any non-Inuit had been at the time.