21 EC speed/RPM question

Capt’nKarl

Well-known member
Joined
Feb 22, 2013
Messages
624
Fluid Motion Model
C-242 C
Hull Identification Number
FMLT2330I718
Non-Fluid Motion Model
Previous R-21EC
Vessel Name
DRAGONFLY
Hello fellow 21 owners. I was wondering what is your average cruising speed and engine RPM and max speed and engine RPM of your Ranger 21EC when loaded with 2 persons, full fuel, water and gear? This is in fairly smooth water with little wind.

My 2009 with the standard 3YM30 Yanmar cruises at 6.2-6.5 kts @ 2400 RPM. Max speed of 7.2-7.5 kts @ 2700-2800 RPM.

thanks,

Capt'n Karl
 
Capt'n Karl,

Your top speed and rpm are too low. That engine has max rated rpm of 3400 and it should have a prop that allows that rpm, 3400+-200. My former tug would max out about 9 knots, 10+ knots surfing down waves.


gene
 
I will do 5.5kts at 2700 fully provisioned for a 2 week trip. This includes 2 people, 5 gallons extra fuel, 15 gallons extra water and either towing 2 plastic kayaks or pulling them into the boat if weather does not permit towing.

Around home without all the extras I will get 6.5kts at 2700 and about 7.5 or 8 at 3400. At 6.5/2700 I am burning 2.5 liters an hour.

Dave
 
In calm conditions, with fuel tank full, and myself only aboard (250 lb), I was making 7.2 kts at 3000 rpm.
Alex
 
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