Complex sentence: Between 1793 and 1805 the U.S. military manned the fort, and spent $16,000 dollars on the garrison at Point Peter, and in 1806 dismantled the garrison in favor of relying solely on gunboats and a fixed battery.
Split into simpler sentences: Between 1793 and 1805 the U.S. military manned the fort, and spent $16,000 dollars on the garrison at Point Peter. However, in 1806 dismantled the fort, relying isntead solely on gunboats and a fixed battery.