BoatBanter.com - View Single Post - Propeller pitch for Catalina 27 with Universal 18 (14HP) Diesel

In article ,
(Sebastian) wrote:

After testing that our engine reaches full RPM (over 3K) in neutral,
but in gear only reaches 2K, we've decided that the most likely cause
is too much prop. We currently have a 13RH10 2-blade prop. Any
recommendations for what is "standard" prop for Catalina 27? I would
guess a 13x8 tops? Also, any ideas for which particular prop to buy?
Don't want to shell out big bucks for Maxprop, so thinking of going
with campbell 3 prop? Thoughts?

Thanks.

I agree with others that you should check the prop manufacturers -- and
that there may be something else going on here. 13x10x2 seems to be in
the right range and you should be pulling within 2-400 rpm of maximum.

Perhaps the engine isn't putting out rated power? Remember, you have to
be moving to pull full revs (and power). I doubt we can pull much more
than 2500 at the dock, but achieve the target 3400 (and 7 knots) on the
water.

A fixed three-blade prop creates a LOT of drag under sail and doesn't
help much while motoring. If you're not getting harmonic vibration near
max power (as we had), a 2 blade is more efficient and will drive the
boat faster.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/