H36 3YM30 cruising RPM

[Ken Honeycutt]

Getting ready for an extended cruise this WE and was wondering what RPM others are using for cruising purposes . I know there has been some discussion on the recommended RPM's for various Yanmar's but I can't seem to find the threads. The 3YM30 has a max RPM of 3600 and I think I saw somewhere ojn this site that extended cruising RPMs should be around 90% of peak RPM which would be around 3200. I generally run between 2800 and 3000 which gets me a little under 6 kts. but because of a tight schedule for the first 2 days I'd like to run a little faster if the wind doesn't cooperate..

 

[chuckwayne]

Ken,
generally 80% is considered optimum fo extended cruising but you can certainly go higher- your speed depends on your gearbox and prop as well, but the 3 series engines are very durable. we run our 3gm30 at around 2800 rpm for extended periods but will run up to 3400 rpm if we're fighting a current. if you're running hard i'd back off every once in a while and let the engine cool down. make sure you've got good water flow out the exhaust

 

[MichaelStacy]

3YM30 Cruising RPMs

I have a 3YM30 on my 2004 H33 and cruise at or below 3000. But, when my wife wants to get back sooner, I run it at 3200 for hours on end. The manual gives a guideline for RPM's. Something like 3400-3600 for short bursts (5 minutes??) Don't recall the details because the manual is on the boat.

Michael

 

[Steve Dion]

Ken: Here is a link to the Yanmar Help website. Most of the engines are to operated at the percent of max rpm. Good luck on your trip.

http://www.yanmarhelp.com/operate.htm

 

[MsEmee]

Diesel engines are made to run at high RPM's with a load on them. So running them at max RPM's is good for your engine. However, running your engine at low RPM's is bad. I believe it is called wetting. We all like to save on diesel when going on long trips. Running at 80% is a good number for economy. So don't worry about running your engine at max RPM's if you need to. I just put a Campbell Sailor Propeller on my boat last week. I get to hulll speed at 3200 RPM's now.. I also get 3/4 of the wind speed for boat speed when sailing vs 1/2. It was a great investment.
If one is running the engine, don't forget to motorsail. Usually one can get an extra 1/2 to 1 knots running with the main up. Also, I found the boat is more stable. Hope this helps.
Melissa
2006 Hunter 36

 

[Paul356]

I use 3000, and have also gone to 3200 for extended periods. The manual was pretty specific on max and indefinite rpms, but like Steve, my manual and log notes are on the boat. I note this quote from the website listed above, and I have been doing this as well (listening to the boat and seeing what's smooth, rather than slavishly following a tach that is probably going to be off 100 rpm or so anyway):

"If the engine VIBRATES unpleasantly at a particular rpm, don't operate it in that rpm band or it will eventually break! Yanmar TACHOMETERS usually read about 100rpm too high at maximum rpm so don't be pedantic about lining up the needle exactly."

Finally, note that top-end rpm, upon which the percentages are based, varies from boat to boat, especially depending on the prop. My top end dropped some when I got a new prop, and I adjusted my rpm ranges accordingly.

Stop in at SSYC in Milwaukee on your way north! Always good to see another 356 or 36.

 

[Andreas7699]

I have had several Yanmars and all have cruising rpm at 400 revs under max rpm.

 

[Ken Honeycutt]

Thanks for the quick answers!

If the weekend forecast holds up - the first day will be a reach with 12 -20kt. winds Still have to motor the second day to get my crewmate and his wife reunited before she bans him from sailboats for life (of course if the weather gets real crappy all bets are off) so I may have to push the engine a little harder than usual..