He seems like a classic opportunistic, dynamic, rather hot-headed ESTP to me. He lives in the moment, frequently acts on impulse, sometimes to his own detriment, tends to indulge his sensual pleasures when he gets the chance, and is skilled at taking opportunities as they come along, reacting quickly and decisively to unexpected events to turn the tide of battle in his favour. For example, his capture of a Spanish frigate with his undermanned, damaged sloop (don't remember the book or the names offhand, just the event) comes across as a classic piece of sucessful ESTP con-artistry - he wins the battle through sheer bluff, impulsivity, and ability to read the situation as it unfolds and improvise a plan accordingly.
He sabotages his career on several separate occasions through impulsive behaviour, and apparant lack of concern for the consequences of upsetting his superiors and rivals, but eventually through ability and a certain amount of luck gets it back on track. He's a relatively easygoing commander, who always seeks to encourage his men and stimulate their enthusiasm where possible and tap into their competitive natures rather than enforce rigid discipline. I could go on, but this is getting boring, especially when it's a long time since I've read the novels. I have a hard time seing him as any type but ESTP though.