You are correct in your thinking. The component is called a spray rail and is mounted at the chine line from bow to stern. The spray rail provides additional lift so planning can be achieved at a slightly lower speed, and at the same time deflects the spray down and out from the side of the boat at speed.
You would actually be better off with motors that have a KV rating of less than 1000. I have a 48" Elco PT with three 780 KV's on three cell lipo's, 40mm 3 blade props, scale planning speed is obtainable at approximately 45% throttle. Very little load on motors, no cooling necessary on motors or ESC's. You will also find low speed operation much more manageable.