If the weapons in Fallout weren't already creative enough for you, there's another one buried in the game's code that just might float your boat.
Modder xxdeathknight72xx has been rooting around in the files and discovered a big ass harpoon gun, complete with underwater animation when you fire it.
The wake of bubbles created when the the gun is fired may point to a scrapped underwater quest or upcoming DLC that will have you scuba diving in the irradiated green waters of the Commonwealth.
If you want to be a harpoon-toting sea dog scouring the wasteland for your own white whale, you can download the mod here. It'll take the place of the railway rifle in your inventory, and you'll have to use console commands to scare up ammo whenever you need it.
Don't forget to check out our Fallout 4 guides for more awesome weapons, collectibles, and tips.