Hello to everyone.
I got lochin 33 fly. sport fish.
2X 300hp Perkins sabre.
Ratio 1.53:1
Propellers 22x21
I'm running the boat about 4 years and got a story recently about the boat. The propellers been change about 10 years ago "electrólise problem". Since that!!! The boat never been the same as new.
Clean hull, fresh paint....
Maximum 2150RPM about 19 knots.
Should do 2400RPM with 25knots.
Any help about the right propellers????
Aprecieate any information.
Best regards
Which perking engines do you have? M300Ti or the newer M300C?
I have some experience with perkins engines and the older models do not produce the power output they claim. This has a big impact on propeller size
How many blades do your props have 3 or 4? Also do you know the blade area ratio? A picture of the props would help.
I know that the M300ti actually produces in the region of 275-280hp not 300hp. I have the official documents from Perkins to show this as I had the same issue with the M265ti engine and propeller size. Turns out it produces about 240hp not 265hp.
Your engine should be able to reach rated speed of 2500rpm under full load, if not then your propellers are too big. Mechanical governor on these is approx 2700rpm but their rated max power is at 2500rpm.
I would expect a Lochin 33 with twin engines of this size to reach around 25 knots but your engines need to be able to reach their full speed.
Also ensure gearbox is good, engine mounts are sound, hull is clean, shaft bearings etc are all in good order, turbo is good and engine is making full power.
