local water = {}
local tiles = gettiles()
for _, tile in ipairs(tiles) do
    for i=1, #tile.items do
        if tile.items[i].id == 622 then
            if tileshootable(tile.posx, tile.posy, tile.posz) then
               table.insert(water, {tile.posx, tile.posy, tile.posz})
            end
        end
    end
end

local pos = water[math.random(1, #water)]
if #pos > 0 then
   local posx, posy, posz = pos[1], pos[2], pos[3]
   useitemon('3483', posx, posy, posz)
end