Power Setting, Universal 25

[Inter20sailor]

Hello Lads,

Having come to the Cat 30 (1991 MkII) from various skiffs and high performance dinghies, this is my first 'lead' boat, and I am looking for some general information regarding power settings.

I have the Universal 25, and this weekend took it out for the first time. Upon leaving the marina I opened it up and read about 3400 rpm on the tach. So, for this conversation, that is my red line.

What is a good power setting that would yeild
1. Best power/ Speed ratio (fuel burn as well)
2. Best power setting to use if I wanted to be 'good to the engine'
3. Best power setting to use light air, sails up.

I hope these questions and scenarios are realistic.

Thank you all...


If it matters, I am in the Seattle area.... and sail tuning/ trimming questions are next

 

[Bob S]

I usually cruise my M25XP @ 2300 rpm. I never checked my fuel consumption but I believe running your engine @ about 75% is where you want to be to be good to your engine and to obtain the best fuel economy. The maximum you'll push your boat is 6-6.5 kts based on the length of waterline. Depending on your prop you will reach that before you reach your red line.

 

[Stephen K]

My maximum RPM is about 3,200 - 3,300 and something around 70% to 80% (2,200 - 2,500RPM) is a smooth cruising range and good fuel economy. I try to find a "smooth spot" that minimizes vibration.

"Being good to your engine" may actually be different from your previous gasoline engines. Diesel's like to be run and need to be run up to temperature. The worst thing for a diesel is to run it for 5 - 10 minurtes then shut it off to sail. I am on an inland lake and struggle with this. My engine mechanic recommends running at 90% for two hours every couple months (or more). I usually do this around 2,800 RPM. The main thing is getting up to temperature to burn off any water and other stuff that accumulates in the oil.

Being good to your engine also means changing the oil and oil filter every 50 hours...to remove the impurities that accumulate and are not be burned off. This is very easy to do yourself on your M25 as you should have an oil drain tube coming from the bottom of the oil pan. You can search the archives for instructions. Don't forget to change the tranny fluid as well.

Welcome to the C-30 gang. I would also recommend that you join the C-30 national association. You will get a lot of help here and on the association web site at www.catalina30.com Best regards.

 

[valcour]

Form the m-25xpb operators manual (http://www.c34.org/manuals/Operators-Manual-1of2.pdf) page 10:

Idle is recommended 1000-1200; cruise 2000-2500; max 2,900-3000. I run my m25xpbc at 2,400 and get 0.6 gal/HR pushing a catalina 310 at 6 kts in flat water with a 15RH19 three blade prop.