All, I just bought a 1998 Glastron 205SF with a Volvo Penta 5.7GS SX. The boat is from California and now it is back here with me in Utah. I operated the boat in Lake Mead with the prop on the boat and I think it was a 19 pitch. I have been told that I need a new prop for the lake altitudes here of >5000ft (most of them in northern UT). So, I thought it prudent to go with one of the ProPulse adjustable props since not only is it better for when I travel to lower altitudes with the boat such as Mead, but it is also sacrificial. <br /><br />So, I set the Propulse at 19 and went out yesterday and the whereas the boat easily did 57MPH on Mead, it only made 42MPH at WOT here at Jordanell Reservoir in the SLC area. <br /><br />Can someone tell me what the best setting would be so that I don't have to play around with it too much. I would like the best balance between get up and go and top speed. So long as I am doing 50+ MPH I would be fine. <br /><br />Finally, do you think I will need to have any other adjustments made to the engine due to the altitude change? <br /><br />Thanks