Controlling an SUP in the whitewater

The fact that SUP's are confined to small surf or breaks with easy paddle out channels hasn't been publicised, but it is obviously true. What bothers me is that people use them at breaks where there's an easy paddle out in conditions where they can't control the boards when caught inside, that's wrong and negates the 'waterman' image which the marketing tries to project.Keep in mind that I have been riding a huge variety of very large boards for many years, and have been building and riding longboards of 27 inches wide and more long before the SUP craze. I don't wear a leash and therefore have a very good understanding of what it takes to control a big longboard in surf up to 4x overhead.For big boards to be controllable they need the following features:1) Weight. For a board to be rolled successfully it needs to be heavy enough to drive the rider underwater, a minimum weight of 25 pounds is needed although it does depend upon how much wetsuit buoyancy the rider has. 35 to 70 pounds works better.2) A thin board with a low frontal area. Boards which approach 4 inches thick are a bane when rolling under as they catch the force of the wave too easily . That's why buoyancy is better distributed over a longer board, and is one reason why the very short thick high buoyancy SUP's are always going to be hopeless at getting through whitewater3) A rail which is thin enough to be gripped strongly. With hands of my size ( average I presume) a board thickness of more than 2.25 inches makes the board much harder to hold on to as the grip strength decreases when the hand has to be opened up more gripping the rail4) Two hands available.5) A helmet. Not absolutely vital but helps a lot when getting hammered while rolling under big sets as the board can be pulled down on to the head increasing grip strength enormouslyThis 65 pound 17 footer is easier to roll under waves than a thick lightweight board of SUP dimensions