RPM's for a Yanmar 2GM20F

[Jaqun]

Hey,
Wondering what RPM's those of you who have a Yanmar 2GM20F are cruising at?
Have a 30ft Freedom running top of 2800. Curious if I should push a little more?

[Island Time O25]

What top speed do you get at 2800rpm? Assuming favorable/neutral weather/sea conditions.

[Jaqun]

between 4 and 5 knots

[Wotname]

Ideally you want to be able to get the rated max RPM at WOT (given a clean bottom, clean prop and calm water).

For a 2GM20F, that is 3,600 RPM. Note, max continuous RPM for this engine is 3,400.

If your prop is pitched correctly, in a Freedom 30, you will probably reach hull speed well below max RPM (clean bottom etc).

In light conditions I use ~ 2,200 RPM for easy motoring and ~ 2,800 for hull speed with my 2GM20 in a 31' Van DeStadt. I can (and will) use 3,400 RPM if needed if the wind / sea conditions dictate.

Yanmar recommends that if using lower RPMs for long periods, increase RPM to maximum periodically.

[Ken Z]

I max out at 3700, I cruise at2200-2400 at 4-5 knots, I have held it at 3400 for a couple of hrs. in severe storms aganist the wind. I feel good at 3000 for extended periods.

[svHyLyte]

We had that engine in our prior boat, a 1976 Cal 2-29, and routinely cruised at 2750 RPM doing 5.5 to 6 knots. Frankly, though, unless the props are the same it would be difficult to compare the engine performance in various boats mentioned by respondents, eh?

[bil56]

the maximum torque of the engine is about 2500 rpm, this is where the speed of the hull must be reached on quiet sea.
as the gear ratio is fixed, it is on the diameter and pitch of propeller that it's necessary to work ...
(high rotation speed = consumption, noise and wear)

[Gary Mc]

Originally Posted by Jaqun

Hey,
Wondering what RPM's those of you who have a Yanmar 2GM20F are cruising at?
Have a 30ft Freedom running top of 2800. Curious if I should push a little more?

You should be at hull speed at 2800 RPMs. If not than your prop is likely the issue.

I have a 30 foot boat with Yanmar 2GM15F and a Gori folding prop. I reach something close to hull speed at about 2400 RPMs. Friends with the same boat and engine but another brand of folding prop have to go to 3200 RPMs to get the same boat speed.