[Butter]

I have a yam 50hp 2 stroke with a four blade prop with a 12 pitch. It came with the boat and i have been running  this prop since. It has a good hole shot, but my top end is around 25mph and 26mph on a good day according to gps . I do not have a tach to see rpms and not sure if this is the right prop or wrong prop. I understand a 3 blade will give better top end but losses quicker hole shot. I heard someone say i should be running a 3 blade prop on my tunnel since i do not have a jack plate. Any info or suggestion will be much appreciated.

 

[swaddict]

I have the 17T with a 60 hp and this is what I run and why.  Started with a 3 blade and boat would run mid 30's, but I wanted to get better hole shot.  Guys at Power Tech emailed me the following, "The SCD4R15PYM90 should be the fastest, but the least grippy of my 4-blades and would probably need to run in the lowest, or next to lowest mounting position.  The RXB4R14PYM90 should be a bit slower, but have more grip and motor elevation capability, and could probably come up some. The SWW3R14PYM90 should run similarly in speed to the RXB, but have similar, if not more, grip. The SWW4R13PYM90 would have the most grip and motor elevation capability, but would probably be the slowest.  I think our range on all props would be from 30-31 to 35-38 (One of my test reports showed a 1700T/C60 that hit 41 with the SCD4R15, but I wasn’t on it, so I think it might be optimistic.)."  You prop will be a smaller hub, so your performance will be different, but gives you an idea. The first thing to do is get a Yamaha Tach, installation is pretty simple.  That will give you a starting point to determine where your current prop is running at, (RPM).  My opinion is that boat runs best with a 4 blade, utilizing the design of the tunnel.  The boat does not need a jack plate to run good, although it couldn't hurt.  You might be able to move the motor up a few holes on the transom

 

[Butter]

Thank you for your time and help, much appreciated.... I will get a tach installed and go from there. Will update my results later. again thank you for your time.