Results 1 to 3 of 3

Thread: prop question

  1. #1

    Default prop question

    I need some help determing the right prop. The boat is a 25' kingfisher about 4300lbs. I started with a 141/4 x 17 3 blade SS. It worked well but did not have the top end I was hopeing for.I than went to a 14 x 19 3 blade SS. It has great top end and a higher cruise that I was looking for but is a little slow getting on step. Also the main thing I am wondering about is at cruise say 4700 - 4800 rpm as the boat enters a wave I loose about 300 rpm and than it comes back, it is a constant roller coaster of RPM's. the engine is a 225 Honda.
    Here are the numbers
    max 6300RPM @36knots
    cruise at 4800rpm @24knots
    no surge in RPM's
    max 5600 rpm @34knots
    cruise at 4800rpm 28knots
    surges with the swell 300 rpm

    Fuel is about equal if you calculate the distance traveled

  2. #2


    Heres a site with a "prop wizard" may be helpful. I haven't used it myself so I cant speak for the accuracy.

    Good luck

  3. #3
    Member spoiled one's Avatar
    Join Date
    Apr 2006


    If you take a look at the specs for that motor off the honda website, honda says the wot rpm should be 5000- 6000rpm. The research I have gathered for these 4 strokes recommends the upper half of that range, so it seems that you are a bit underpropped with the 17" and just about right with the 19". Personally, I would like to see max (or at least 5800) when fully loaded. Solas makes a 14.25 x 17 4-blade that might work out well for you. generally speaking, a 4-blade will give you better economy at cruise, improved hole shot, and a bit more stern lift. I run those props on my set up and have been satisfied, but am always looking for improvements.
    Spending my kids' inheritance with them, one adventure at a time.


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts