Motoring Speed

[jbstack28]

Hey question I have the Universal 25xp motor (25hp) and a max prop three blade.  What should I be motoring at she will only run like 5 - 5.5 at 2600 rpm.  Seems low from what I hear from others.  

Thanks

Charlie Stackpole
'DESPIDO' 1990 Hull 1029

[cholder]

I have a 25XP with a fixed three blade prop.  With a clean bottom and calm conditions we can motor at about 7 knots.  With some slime that builds up over the summer the speed drops to about 6.5 knots.  Waves and wind against us, the speed can be further reduced by maybe another knot. However, my first question would be have you calibrated your log against a measured distance.  My log as a calibration that's more than able to make us appear really fast or incredibly slow.

By the way, at 2800 rpm we do about 6.7 knots with a slimed bottom and a slight chop.

[jsbbritt]

Are you using a GPS to check your speed?  I have the same set up as you and I consistently get around 6.5 at 2800rpm.

[jbstack28]

Thanks for the information.  I have not calibrated the log however I have compared to both the GPS and other boats.  Jim can you give me your pitch settings on you prop.  Perhaps it needs to be adjusted.  Come on guys please help me figure this out.  Last weekend I ran into a storm with some wind and was down to 2.3 boat speed.  

Thanks

Charlie Stackpole
DESPIDO 1990 #1029

[skip]

Charlie-

Also have 25mx with max prop 3 blade 15".   I do close to 6.5 in calm water at about 2800.   I purchased the max prop a year ago.  It is an adjustable pitch that you set at installallation and it is hard to follow the instructions to determine the settings.   I think that I set it at around 10-11 pitch. Perhaps your setting is too low?   Unfortunately you have to wait until a haul-out and dissassemble the prop to re-set the pitch

-Skip

[jbstack28]

Thanks Skip.  I am in process of contacting PYI for there recommended setting for this engine setup.  I will post as one last reply when I get the information.  You are right about the haulout.  I guess I may wait till next bottom paint time.  

Charlie

'DESPIDO'