My engine operates with full throttle at about 3200 rpm's which gives be about 5.5 knots subject to wind conditions. How can I get more speed?
Captain
- Thread starter peterhambly
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Bigger Engine Maybe ? ? ? ...................
............... but seriously, your first step is to find out why you can't reach (and I'm guessing here without having any info about your engine) 3600 RPM.
A few more details about your engine would go a long way to providing answers to the problem.
............... but seriously, your first step is to find out why you can't reach (and I'm guessing here without having any info about your engine) 3600 RPM.
- Check for any restrictions in the exhaust system such as the mixing elbow being plugged.
- Can you make 3600 RPM in neutral ?
- Is the prop clean ?
- Is the hull clean ?
A few more details about your engine would go a long way to providing answers to the problem.
how about engine make and model? Hard enough to guess at things without having to guess what were guessing about. 
Response
The engine is the one that came with the boat when I purchased it new in September, 2003. It is a Yanmar - Model # 3GM30F. It has a continous rating of 3400 RPM and a maximum rating of 3600 RPM.
I find that I need to hold the gas lever in position to keep it above 3200 RPM. It usually settles back to 3000 RPM. When I have held it at 3600 RPM I find that it uses oil.
The engine is the one that came with the boat when I purchased it new in September, 2003. It is a Yanmar - Model # 3GM30F. It has a continous rating of 3400 RPM and a maximum rating of 3600 RPM.
I find that I need to hold the gas lever in position to keep it above 3200 RPM. It usually settles back to 3000 RPM. When I have held it at 3600 RPM I find that it uses oil.
There should be a drag adjustment somewhere on the controls to keep it from creeping. It should stay where you put it, not fall back. Fix that and your problem should go away.
It uses oil at 3600 because its not supposed to run at that rpm except intermittently. Think of it as emergency reserve power and dont go there unless its an emergency. And then only momentarily.
It uses oil at 3600 because its not supposed to run at that rpm except intermittently. Think of it as emergency reserve power and dont go there unless its an emergency. And then only momentarily.
My neighbor tells me that he has very good results with a varipropeller. He has a Beneteau 34. Does anyone have any experience with this propeller on a Catalina 32 with a Yanmar engine?
Also keep in mind that there is a speed which, regardless of horsepower, the boat will go no faster. It is known as the theoretical hull speed, and is based on a number of factors...weight, beam, draft, etc. all have an effect on boat speed. I would guess that even under optimum conditions your boat will only do 6.5 knots or so. If you're making 5.5 knots you are probably not doing all that bad. Make sure the bottom is clean and try again.
As far as the prop goes: if you are making 3400 RPM, I think you are pitched correctly. A finer pitch will give you higher rpm, but the engine isn't designed to run that fast. A coarser pitch would only slow the rpm, and the boat, down.
As far as the prop goes: if you are making 3400 RPM, I think you are pitched correctly. A finer pitch will give you higher rpm, but the engine isn't designed to run that fast. A coarser pitch would only slow the rpm, and the boat, down.
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