But beyond that, privateers were fairly successful. In general they were no more or less ruthless than the regular navy of the times. And you could say that both regular navy and privateers were motivated by profit. Both took prize money of some sort, the only difference is that the navy paid out as determined by the admiralty court or other official, and the privateer had to actually sell the stuff.

Also, privateers don't fight pirates unless they have to, they fight cargo ships. It wouldn't take much to take one of those over, they have so few crew. The harder part would be fencing the cargo.