Find the 5 pieces of the map and examine it and you'll see where skullduggery is. Dock there then get out of there and you'll find captain crawfish
your
You Can't
His username is "captincrawfishcreator"
No, you must have the Pheanox Warbird.
you buy bigger ships
You use it in Captain Crawfish's dream.
Rather than sinking, Captain Crawfish runs away when you beat him. That is enough for the governor. Go back to see him and he gives you the treasure location and the bone shovel.
Captain Crawfish is defeated in battle on Skullduggery island, but appears again as a character on Super Villain Island (2012). He spends all but a tiny part of the island asleep.
You will need to amass your doubloons to buy larger ships, because only the largest, the Phoenix Warbird, stands a chance against Captain Crawfish. (see related question)
It isn't possible. The whole point of getting a big ship on Skullduggery Island is so that you can fight an even battle against Captain Crawfish. There are no magic shortcuts that work on Poptropica.
It is possible that he could have been a real pirate but there are no records?
Once you have all 5 map pieces, one from each island, the small island appears near the Pirate Outpost. This is where Captain Crawfish generally appears even before the island becomes visible, but you can sneak in and dock rather easily. There is, however, nothing to do there until after you have beaten Captain Crawfish and gotten the treasure location from the Governor.