The Leed agros on boats, so create a motorboat. It will agro but because the motorboat is metal It will do barely any damage to it. As the Leed is agro-ing on it, jump in the water with your sword and scrape meat off. Then just hop on your boat and precede with your day
It will attacks rafts so be carful coming across one on a boat.
Also the Alpha Albino Leedsichthys Will give you raw prime fish me when you scrape meat off of it, and killing it will give you The Captains Hat Skin