Hi Austin,
This porpoising issue is known and not unique to Ski Centurions...meaning others have had issues with Mastercrafts etc. It is definitely a weight issue compounded by water flow. The boat is obviously very sensitive to weight distribution and the mechanics of it are totally based on the fact that the prop shaft comes out of the boat at an angle.
The simplest fix is exactly what you said. more weight in the nose. You can use bags of sand. Or, you can go to wakemakers website and look at lead that is used as ballast in wake boats. Or, you can buy a ballast bag and fill it up with water. That gives you some adjust-ability.
So, Mastercraft fixed this by putting a hook at the end of the bow. Shaped like a reverse spoiler, the hook was fiber-glassed in to the hull of the boat and it forced the nose down through the use of water pressure. There's a thread over on Team Talk (mastercraft board) about how to make one of those if you like.
Also, as you mentioned, the cavatation plate on a ski centurion is fixed. You could take that off and re-attach it with a piano hinge. Then, you could hook it up to a pair of lenco actuators and that would allow you to trim the boat slightly. Just know that if you have to have that down some to get to 36 mph (if that's your preferred slalom speed) It will have an impact on the slalom wake. But, if you slalom at 34 and that's just below the porpoising speed and you add this adjustable plate just for cruising around the lake, then that might work for you too.
When we built my boat, we speculated that our rebuilt structure that we used to make the seating area in the open bow weighed more than what was there previously. That had the desired effect of causing the nose to ride even lower in the water. As a result, less of the back of the boat is in the water as it pivoted along the center axis of the boat based on front to back weight distribution. This generated a better slalom wake. Everything is a trade off, the boat is pushing a bit more water with nose down a bit, and that adds height to the ramp of the wake, but with less effect from the back of the boat everything is soft and small. Weight in the front can act against all the weight in the rear that is present when you have a full tank of gas sitting back there.
I don't know if this does, but I hope some of this helps. Enjoy!
-Tim
