The peacetime United States Navy retained more officers than its available ships could employ. Those officers provided personnel for a possible wartime expansion, even when the service had little immediate work for them. Semmes spent much of the 1830s studying law and qualified for the bar. His naval career therefore included substantial periods ashore, with legal training developing alongside his experience at sea.
Notable Point · 4:15-5:17
Why the peacetime US Navy retained surplus officers
The Navy retained officers for wartime expansion even when peacetime ship appointments were scarce, leaving Semmes time to study law.