[C320-list] Normal Performance Limits?
Kirk McCullough
kirk.mccullough at telus.net
Sat Oct 4 17:03:12 PDT 2008
Sounds like the knot meter has a problem. If it was current, then at some
point in your travels you would have contrary current and your knot meter
would read higher than your SOG.
You can calibrate the knot meter on a measured course or use the GPS reading
at slack tide conditions to get it reading more accurately.
I can't comment on your water problem.
Kirk
#124
----- Original Message -----
From: "Jack McDonough" <mcdonough5 at verizon.net>
To: <C320-List at Catalina320.com>
Sent: Saturday, October 04, 2008 10:22 AM
Subject: Re: [C320-list] Normal Performance Limits?
>
> Bert:
>
> I understand the analogy. But it seems to me that my knotmeter must be
> registering unrealistically low speeds when it always, and I mean always,
> shows one or two knots less than SOG. And this also happens when running
> under power only. It seems doubtful to me that the difference is always
> current. Anyway, I consider this to be more a situation than a problem to
> be solved.
>
> The leaking fresh water connector under the head sink, on the other hand,
> is a problem. I'm not getting any takers on that one. Apparently no one
> else has had the same experience.
>
> jack
> sure bet #947
>
>
>
> ----- Original Message -----
> From: <BAdams3491 at aol.com>
> To: <C320-List at Catalina320.com>
> Sent: Saturday, October 04, 2008 9:07 AM
> Subject: Re: [C320-list] Normal Performance Limits?
>
>
>> Jack,
>>
>> Using speed over ground is fine for determining when you'll get some
>> where.
>> However, it tells you nothing about how your engine is running as far
>> as
>> speed is concerned. If an airplane is flying at 200 knots, but has a
>> 50 knot
>> headwind, it's only going 150 knots over the ground...same with a boat
>> only
>> the variables are wind, current, tide, etc.
>>
>> Bert
>> At Ease
>> #442
>>
>>
>> In a message dated 10/4/2008 10:21:37 A.M. Central Daylight Time,
>> mcdonough5 at verizon.net writes:
>>
>> Monte & Bert:
>>
>> My 320 is now on jackstands for the winter after another short New
>> England
>> season. Now I'm eager to get in the water in the spring to see how the
>> engine sounds at 3000 to 3600. It has always seemed to me that it
>> "sounds"
>> like it is content at the lower rpms.
>>
>> Additionally, I have always thought that the knotmeter reading was lower
>> than the actual speed of the boat through the water. It regularly
>> records
>> speeds in the 3, 4 and 5 knot range when I'm certain I'm going faster
>> than
>> that by any visual estimate. That's why I pay more attention now to the
>> SOG
>> when I'm intent on getting where I'm going.
>>
>> And, while I have your attention, has anyone read my earlier e-mail
>> about
>> the leaking fresh water connector under the head sink?
>>
>> Jack
>> #947
>>
>>
>>
>> ----- Original Message -----
>> From: "Monte B." <mjbc60 at sbcglobal.net>
>> To: <C320-List at Catalina320.com>
>> Sent: Saturday, October 04, 2008 6:32 AM
>> Subject: Re: [C320-list] Normal Performance Limits?
>>
>>
>>>I have owned mine since new in 1999 and have accumulated about 750
>>>engine
>>> hours. For most of those hours I ran it very conservatively at 2500
>>> RPM's
>>> and not quite 6 knots. After reading the posts about exhaust elbow
>>> coking,
>>> I
>>> pulled my ex. mixing elbow and found it to be quite coked but nowhere
>>> near
>>> plugged as some have reported. I now run it at 3000 and it is actually
>>> smoother at that RPM and obviously faster at the expense of a higher
>>> fuel
>>> burn. I think Yanmar calls for max RPM of 3600 and max continuous of
>>> 3400.
>>> I
>>> have come to believe that diesel's like to work near their design load
>>> limit
>>> and at lower RPM and load tend to run rich and the lower exhaust gas
>>> temperatures cause exhaust component coking. I don't know how they
>>> avoid
>>> this with automobile diesel engines but they are not designed to be
>>> continuous duty cycle as these small industrial and marine engines are.
>>>
>>> Monte
>>> Laima #620
>>>
>>> -----Original Message-----
>>> From: c320-list-bounces at lists.catalina320.com
>>> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Jack
>>> McDonough
>>> Sent: Saturday, October 04, 2008 7:37 AM
>>> To: C320-List at Catalina320.com
>>> Subject: Re: [C320-list] Normal Performance Limits?
>>>
>>> I've had my 320 since it was new in 2003 and I have never run my Yanmar
>>> 27
>>> much more than 2600 or, rarely, 2800 rpm. With a three-blade prop, I'm
>>> probably doing about 6 knots over the ground. My recollection is that
>>> those
>>> rpms are about what the engine mounting plate and the Catalina manual
>>> suggest. Am I right or wrong?
>>>
>>> Jack
>>> #947
>>>
>>>
>>>
>>>
>>> ----- Original Message -----
>>> From: "Monte B." <mjbc60 at sbcglobal.net>
>>> To: <C320-List at Catalina320.com>
>>> Sent: Friday, October 03, 2008 8:46 PM
>>> Subject: Re: [C320-list] Normal Performance Limits?
>>>
>>>
>>>>I didn't disagree with Rod. I reiterate, these instrument systems
>>>>(tachs)
>>>> are poorly calibrated and if you normally run your engine at a
>>>> conservative
>>>> RPM and then firewall it you may expect to see smoke just from the
>>>> higher
>>>> exhaust gas temp burning combustion deposits out of the exhaust
>>>> system.
>>>> That
>>>> having been said I would agree that prop pitch controls max. RPM.
>>>>
>>>> Monte
>>>> Laima #620
>>>>
>>>> -----Original Message-----
>>>> From: c320-list-bounces at lists.catalina320.com
>>>> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of
>>>> joe at dolphinmortgage.com
>>>> Sent: Friday, October 03, 2008 8:32 PM
>>>> To: C320-List at Catalina320.com
>>>> Subject: Re: [C320-list] Normal Performance Limits?
>>>>
>>>> I agree with Rod, low RPM and black smoke with clean bottom & Prop
>>>> means
>>>> it
>>>> is overpitched. Should run at 3600 RPM at Max throttle.
>>>> Joe Barrett
>>>>
>>>> -----Original Message-----
>>>> From: Monte B. [mailto:mjbc60 at sbcglobal.net]
>>>> Sent: Friday, October 3, 2008 08:53 PM
>>>> To: C320-List at Catalina320.com
>>>> Subject: Re: [C320-list] Normal Performance Limits?
>>>>
>>>> These boats also have notoriously inaccurate tach,s, something else to
>>>> check. Monte Laima #620 -----Original Message----- From:
>>>> c320-list-bounces at lists.catalina320.com
>>>> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Rod
>>>> Boer
>>>> Sent:
>>>> Friday, October 03, 2008 7:12 PM To: C320-List at Catalina320.com
>>>> Subject:
>>>> Re:
>>>> [C320-list] Normal Performance Limits? It sounds to me that you are
>>>> over
>>>> propped. You should be able to get up to 3400 RPM. Can you adjust the
>>>> pitch
>>>> on the Kiwi? If so, just reduce the pitch and you should be able to
>>>> get
>>>> up
>>>> to the full RPM Rod Boer Odyssey, #688 -----Original Message-----
>>>> From:
>>>> c320-list-bounces at lists.catalina320.com
>>>> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of
>>>> Amirault
>>>> Family - S&B Sent: Friday, October 03, 2008 7:01 PM To:
>>>> c320-list at catalina320.com Subject: [C320-list] Normal Performance
>>>> Limits?
>>>> I
>>>> had my boat on the water yesterday afternoon for likely the last sail
>>>> of
>>>> the
>>>> season. Although the wind was 15-20 knots on departure it had dropped
>>>> to
>>>> near nil by the time the crew decided to head for home. To ensure we
>>>> arrived
>>>> at the dock before dark I slowly pushed the throttle to maximum. On
>>>> still
>>>> water this gave me revs at 2900, knots at 6.75 and plenty of black
>>>> smoke.
>>>> On
>>>> easing the throttle back to 2500 revs I was able to maintain 6 knots
>>>> and
>>>> eliminate the smoke. I have a Yanmar 3GM30, a clean bottom and a Kiwi
>>>> prop.
>>>> Is this approximately normal? Brian Amirault #797 Waltzing Bear, too
>>>>
>>>
>>
>>
>>
>>
>>
>>
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>
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