Mr. Joe. Welcome aboard. If the boat is listing naturally the tanks will equalize to that list IF the crossover is open thereby adding nothing to the correction weight. Likewise if the tanks are at equal level and the valve is closed.
As Mr. Q suggested, relocation of heavy "stuff" might
straighten you up. I would ask how heavy is the crane and how far outboard from the center-line is it? How much weight would you have to put on the starboard side to straighten the boat. Try an experiment.
Go to the local store and buy, say, 40 cases of beer (about 800 lbs.) Invited 3 or four of your friends over (gender not an issue for experimental purposes although the "freinds" posted by Mr. Alemao (Favorite pictures thread post #93, frame #'s 2 and 3) would suffice quite nicely). Since only 4 "friends" were shown, you'll probably need more beer, due to females weighing less than males, unless they have some friends.
Put everything on the port side (friends+beer) and see if you've removed the list. If not, buy more beer, say another 40 cases (add another 800 lbs.). Check again to see if you've removed the list.
Now, I'm NOT a naval architect but I would suspect exact placement of the weight (friends+beer) might
be somewhat critical necessitating careful piling of the beer (dead weight) and posing of the "friends" (live weight).
Having achieved a level stance you should then easily how much weight you have to shift and/or add.
In the event you've overcompensated you will, of course have to adjust by REMOVING some of the added weight from the starboard side. I would suggest doing this in a controlled and even manner to maximize experimental results. Since the most ACCURATE way is to slowly remove weight it might be best if everyone drank one beer each. Empty bottles/cans would have to be removed ashore during consumption so as to not skew results.
Continue removing weight until arriving at a position of stasis. NOW yu ca figer it ote..........Peasy easy...