310 Motoring Speed

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Bill Saint

I have a new (used)'97 310 and my knot meter shows about 3.6 knts at 2,500 rpm. I thought it would be faster. Any ideas on typical speed when motoring? I will double check the knot meter with GPS on next trip.
 
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hp

calibrating knot meter

should be faster, double check and recalibrate your knot meter I would guess that it is slow! Remember gps speed and knot meter will difer because of currents however you can run the measured distance using the gps distance to calibrate the knot meter Good Luck Hope this helps!
 
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Mark Roskin

29.5 speed

I do about 5kts @ 2500 rpm with the 29.5. You should do a little better - 5.1 or 5.2.
 
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Kenneth Pfaff

Survey???????

I have seen this question a number of time, all stated differently of course? If fact I have the same question because I am taking delivery of my new Hunter 290 in a couple of weeks and am attempting to plan my trip from the dealer to my homeport. My questions to the group is for you type of boat at what RPM do you cruise at and what is you speed Knot meter and GPS. Or should this be a survey question. I also know that someone's responds will just say 'Check Archive' which is not what people are looking for.
 
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William Berson

Faster faster

It should be much faster with the standard prop and a reasonable clean bottom. My 310 gives an honest 6kts or so at about 2200 RPM. At 2500 we're pushing 6.4, which is about the top. If there are any seas at all, the speed drops down considerable, especially into a chop. Check it out and recalibrate the knotmeter, which is easily done from the front controls. Also, be sure to pull the knotmeter sender and make sure it isn't fouled or worse - is askew, which would mean it ain't rightly seated and could leak.
 
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Steve Cook

My H310 speed

My 1999 H310 with a clean bottom, flat seas and light wind, I see about 5.7 to 6.0 kts. at 2200 rpm. I tend to stay away from 2400 to 2600 rpm as there is an apparent vibration which seems to be normal on the H310. At 2900 to 3000 rpm (wot)with the same wind and sea, I do 7.6 to 7.8 kts on both GPS's and my knot meter. As all others have said, check your knot meter/transducer. Also, check your engine and shaft alinement. Further more, as with all Yanmar engines, there is a compression release on the head of the motor. Check and see if they (2 on your engine) are closed. (see your engine manual). That will surly slow you down!!! Steve, s/v The Odyssey (H310)
 
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Jerry Olivero

Ignorance is not always bliss.

Thought Bill's performance was 'normal' but reading Steve's post has me wondering since I have experienced similar performance on my 98 310 since commissioning. I have verified this performance against 2 GPS and the knot meter at various rpm and have found that 3000rpm = 4.2kts, 2500rpm = 3.7kts 2200rpm = 3.3kts, 1800rpm = 2.4 kts, 1500rpm = 1.8kts, 1000rpm = 0.9kts. The engine runs smooth with very little vibration at all rpms except 2600-2700rpm range. Any other 310 owners have any ideas or insights as to where the problem might be?
 
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Bill Saint

Thanks

Thanks for everyone's insight. I think Steve's results should be expected. My prior Hunter 30 would motor at 6.0 - 6.3. I do believe it is the knot meter I'm having a problem with, as the boat speed did not feel all that slow. I will check out the knot meter reading and verify against a GPS. Thanks again, and I hope we hear from other 310 owners.
 
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Steve Cook

In case you are woundering...

When I go out sailing with other sail boats, there is "not" another sail boat in my marina that can keep up with me under motor!!! I spend a lot of time making sure my motor and shaft are aline and that everything is well maintained. This will be my 3rd. season with my 310 and as of right now, I only have 127 hours on the motor (not even broken in yet). I have checked my speeds with other boats also. I think everybody should be getting more speed out of their 2GMF and their H310. Steve, s/v The Odyssey ('99 H310)
 
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Jerry Olivero

Steve, was wondering???

Do you have any magical potions to throw this way that would make my 310 go faster under power. I am currently out of the water for the first time since commissioning, preparing to clean, sand, repaint the bottom and other routine below the waterline maintenance such as several new thru-hulls (new sensors for electronic gizmos), clean prop, inspect rudder and inspect keel before a mid-April relaunch(weather permitting and the river rises). I am open to any guidance you might offer as to what I should be looking for to explain the difference in motoring performance betwen my 98 310 and your 99 310. I will definitely check shaft alignment as you have suggested but my thinking was that since I am not experiencing any vibration the shaft was not misaligned. (correct???) This is my first sailboat with an inboard diesel so I definitely am a rookie when it comes to the feeding and care of the iron genny but I am definitely motivated to learn about the dark side (mechanical/structural maintenance).
 
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Steve Cook

Jerry...

I would check your decompression valves on the engine head to be sure they are closed. Other than that, I don't know what to tell you. Maybe you should talk to you yard service manager. Something is not right with those speeds. Hell, my old H27 with a 8hp. diesel got 5.5 kts.(wot) I have a buddy with an O'day 322 with the same engine we have. His boat displaces almost 3000lbs. more than us and he motors at 6.7kts. (wot) I would really have that checked out! Steve.
 
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