Last summer I purchased a new Nitro Z-7 Sport. The boat is 19 ' 6" long and powered by a Mercury 150 Pro XS. Due to a severe drought in Texas the first time I was able to use the boat was on Table Rock lake in Missouri. At the time I was unable to trim the engine without either plowing through the water like a barge or porpoising. I could get the boat on plane but only if I did not trim the engine at all which limited speed and made the boat very inefficient fuel wise. When I returned to Texas I took the boat back to the dealer and their solution was to install a new prop. Subsequent testing has shown that I can trim the prop a litter bit but no where near as much as I have on other nitro boats and speed is still well below the max advertised. Some of suggested the addition of a jack plate to solve this problem while others have suggested the addition of a whale tail. I'm curious as to why either is needed as my prior nitro (a 1999 FS 18' 6" with a Mercury 115) needed neither and got up on plane just fine. While the hull design is materially different with the 2011 model my primary concern is whether the motor is even mounted correctly to the boat. I'm trying to determine what my best options are to solve this problem. I'm heading back to Table Rock lake in 6 weeks and don't want to have the same performance issues. Thanks.