Hello all,<br /><br />I have a 2004 18 Chaparral with the 3.0L and an Alpha 1 drive. This is about a 2100-pound boat. It came with a 14.25 x 21P prop. I have been very impressed with this prop so far. It has an excellent hole shot, and a fair top speed even with 4 adults and 3 children on board.<br /><br />Two weeks ago, we were on vacation and tapped some underwater rocks. We were able to finish out the week with this prop, with no real problems. On the way home I found a deal on a Quicksilver stainless prop of the same diameter and pitch. I was expecting better performance out of the stainless, but yesterday when we took it out for the first time since the new prop, I was really disappointed. The hole shot is destroyed, and top speed is also down about 4mph. WOT RPMS are also up a bit.<br /><br />I believe what is happening is that the new prop is ventilating. At least that is how it sounds and feels. This prop has rather large ventilation holes behind the blades. My aluminum prop didnt have these. They are actually shaped kind of like elongated Ds, and are probably roughly 3/8 to 1/2 in diameter. They do appear to be factory holes, as in they dont appear to have been added as an after thought.<br /><br />My questions are; do you guys think this could be my problem? And also is there something (maybe JB Weld) that I can use to plug these holes and try it out? I can easily get them welded in solid, but I thought I should try it temporarily first.<br /><br />Sorry for the lengthy post, but any ideas will be greatly appreciated.