Some boats need them, some don't, mostly because of hull style. I own two boats, both '21 feet and carry the same load in both. One is an '84 Sea Ray cuddy with a deep V hull. That boat needs tabs but doesn't, probably because of the price point when it was built. I move folks around to keep it balanced laterally. Actually, with my family as passengers, they know where to sit. The other boat is a Four Winns deckboat with a cathedral hull. It doesn't need tabs no matter the load.