Hey all!!!<br />I need a little advice. I recently purchased a 1996 Bayliner Ciera 2855 with a 280 horse Mercruiser 350(5.7)and an Alpha One Gen. II drive. She is 30' 3" long and has a dry weight of about 6900 lbs, so she's big. I am having some prop issues. I bought the boat in Chicago (It was ran on the great lakes.) and trailered it to Wyoming. The prop that it has now is a 15P Aluminum. The guy I bought the boat from said he got 25 to 30 mph cruising and about 35 top speed out of her. She had a new engine put in her in 2000. It has about 200 hours on it. I realize that elevation has an effect on what prop to use. (Chicago is about sea level and it's about 5000 ft above sea level where I live.) I took her out for the first time a couple of weeks ago, and realized I need to re-jet the carb. The boat has trim tabs, which I'm learning how to use, but I could only get about 17 mph out of her at 3500 rpm's. I want a good top cruising speed, but also plan to pull tubers and maybe a kneeboarder or two, so I still need some hole-shot and a little low end torque. Can anyone suggest an option or direct me to a website with some info? I was thinking maybe a 17 or 18P? What about 4 and 5 blade props? What is the suggested rpm's for cruising and top speed? Any help is appreciated!