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Old 07-07-2016, 11:27 PM   #21
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H.W.

Spooling. At least with engines usually refers to the turbocharger acceleration

Droop. With diesel engine usually is part of the fuel delivery by the injection pump governor where the engine has reached its Rated rpm but not the final absolute max. Rpm set by the mfgr. The few hundred revs difference between the Rated and the final max. (High idle) is often called the droop. It can be called by other terms but droop is often used.

I hope I haven,t blathers about the wrong issue.
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Old 07-07-2016, 11:50 PM   #22
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Originally Posted by C lectric View Post
H.W.

Spooling. At least with engines usually refers to the turbocharger acceleration

Droop. With diesel engine usually is part of the fuel delivery by the injection pump governor where the engine has reached its Rated rpm but not the final absolute max. Rpm set by the mfgr. The few hundred revs difference between the Rated and the final max. (High idle) is often called the droop. It can be called by other terms but droop is often used.

I hope I haven,t blathers about the wrong issue.
Got it. Those two terms were used earlier in this discussion so you defined the right droop.
Thanks.
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Old 07-11-2016, 10:11 PM   #23
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HW,

Droop I realized I left a wee bit out. The rev difference between Rated and Hi Idle is the speed where the governor starts to defuel the engine as it backs off feeding to not overshoot the high idle. The mechanical injected engines need that spread so they don,t abruptly
defuel.

The electronic ones do the same but the control can be done smoothly in a much tighter spread to the point that dialing in a prop needs some different techniques.
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Old 07-11-2016, 10:58 PM   #24
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Turbos

I'm guessing I'm not the only guy that has purchased a bank repo with no sea trial so not sure why that's coming up
The Bayliner37 with 250 hp 6bta was slightly under powered from what I read so I was looking for info on prop pitch and performance numbers like cruising rpm and speed
I have had a ton of good info on this site that helps me trouble shoot
Yes I have had 2 bayliners that are not great performers but I still enjoy boating and love the 3788
Thanks for all the help
I'm going to look at the props then post back with real numbers
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Old 07-12-2016, 12:09 AM   #25
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The 38 Bayliner, 3788 I believe, was a lobster boat hull copy. Those boats had a good turn of speed but we're not fast boats. Usually designed to be a seaworthy hull in usually rough waters that could also carry a good load without fuel use breaking the bank.

The later real pleasure boat need for greater speed was not intended so original, early 3788, were according to later standards slow and underpowered.
For original intentions and market at the time they filled a niche.
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Old 07-12-2016, 07:00 AM   #26
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2016 Powerboat Guide says 19 to 20 knots cruise and 24 knots wide open. One clue to whether you are over propped or not is how close to the 24 knot top speed you are getting at wide open throttle. If you are near the 24 knots with low rpms then you are probably over propped. If 2200 rpms gives you closer to the advertised cruise speed then you more likely have an engine problem.

In the circumstance you are over propped the engine is overloaded. In the other circumstance the engine is just not making the power. It has been my experience over the years dialing the props in for the last couple 100 rpms doesn't drastically change top speed. It just matches the load better to the engines capability.

FYI those engines should turn 2,600 rpms according to boatdiesel.com


Quote:
Originally Posted by yoeman View Post
I'm guessing I'm not the only guy that has purchased a bank repo with no sea trial so not sure why that's coming up
The Bayliner37 with 250 hp 6bta was slightly under powered from what I read so I was looking for info on prop pitch and performance numbers like cruising rpm and speed
I have had a ton of good info on this site that helps me trouble shoot
Yes I have had 2 bayliners that are not great performers but I still enjoy boating and love the 3788
Thanks for all the help
I'm going to look at the props then post back with real numbers
Attached Files
File Type: pdf Bayliner 3788.pdf (148.3 KB, 15 views)
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