Complex sentence: After reaching the northwest, in March of 1792, a small sloop was constructed, the "Adventure", and Haswell placed in charge, his first command, again plying the coast for pelts.
Split into simpler sentences: After reaching the northwest, in March of 1792, a small sloop was constructed, the "Adventure". Haswell was placed in charge, his first command, and he again plied the coast for pelts.