For solo bounties, I have a small trick who works, at least for now, like a charm.
Weapons: Pistol/Sniper
First, find the enemies, that's the easy part. When you found them, go back to your ship and go near those bony landlubbers. Equip the Sniper and the Pistol, and shoot them from your ship. If you're out of bullets, just reload from your ship. Repeat until the Big Boss shows up.
When the boss shows up, just cannonball him. It can take time to aim correctly but it usually explodes with 3-4 shots, and his friends will burst to bones if they stick around.
Skellies can't swim, so you're kind of safe if you stay on your ship. It just can take some time, because of the very limited bullets.
Why Sniper/Pistol? Pistol is when the enemies are close enough to slay them with one shot or two. Sniper is for the regular headshots.