Cruising speed rpm?

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jeepinocala1111
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Cruising speed rpm?

Post by jeepinocala1111 » Sat Jul 23, 2016 7:23 pm

I am taking a guess at this and saying 3000 is a good rpm during cruise speed.

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Re: Cruising speed rpm?

Post by SWAMPHUNTER45 » Sat Jul 23, 2016 7:33 pm

Gear drive car motor boat it would be a reasonable deep water rpm.

I have seen boats cruise at 2600 and others needed 3600 just depends on boat, ratio, prop and load.

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pontoon outlaw
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Re: Cruising speed rpm?

Post by pontoon outlaw » Sat Jul 23, 2016 9:29 pm

:salute: ole Lightning only needs 2200 to cruise around :lol: with the wind at her back of course :stirpot:

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Re: Cruising speed rpm?

Post by jeepinocala1111 » Sun Jul 24, 2016 10:49 am

Ok so I found a simple issue the prop blades were pitched wrong onemail was at just past three, one was at three, and the last one was just at the low side of three. I set all of them just past three maybe 3.5 this should be good. If there is one thing I have learned all my life it is clearly being able to tell when hp is being used correctly. I have a three Blade r series what's the difference between this and a ngr Blade? I am at 3.5 feeling like I need more Blade possibly. Is it possible these blades can turn in the hub after being torqued down?

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Re: Cruising speed rpm?

Post by SWAMPHUNTER45 » Sun Jul 24, 2016 11:37 am

R blades are probably the best all around blade. The NGR has winglets is a little quieter maybe slight better low end but not to much more than that. They are very close in design if you need more your talking about length or additional blade.

I would get with PTR34, Outlaw or Darrin and see what they think.

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kwanjangnihm
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Re: Cruising speed rpm?

Post by kwanjangnihm » Sun Jul 24, 2016 12:19 pm

jeep I may have missed it, did you buy a CM boat?

let me know so I can take you off the christmas card list if you did!! :stirpot: :toothy7:
Last edited by kwanjangnihm on Sun Jul 24, 2016 7:54 pm, edited 1 time in total.
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BluByU2
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Re: Cruising speed rpm?

Post by BluByU2 » Sun Jul 24, 2016 12:54 pm

I cruise at, or about 2300 rpm with no headwind. Three blade 78" Whispertip, and a 1.53 Rotator.

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Re: Cruising speed rpm?

Post by jeepinocala1111 » Sun Jul 24, 2016 2:26 pm

kwanjangnihm wrote:jeep I may have missed it, did you but a CM boat?

let me know so I can take you off the christmas card list if you did!! :stirpot: :toothy7:
Yes trust me it takes some getting used to. Much better for going anywhere but a barge compared to my old boat. I do regret letting my old boat go but this will be great for hunting it's much more stable. You know how it is buying a used boat you first have to fix the things that are turn key to someone else. I will post the specks but there is no way it will cruise under 3000 rpm from what I will guess. Anyway I can tell someone real quick the difference between a car engine boat and an ac.

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Deano
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Re: Cruising speed rpm?

Post by Deano » Mon Jul 25, 2016 9:35 am

BluByU2 wrote:I cruise at, or about 2300 rpm with no headwind. Three blade 78" Whispertip, and a 1.53 Rotator.
And there is a big torque x small gear example I eluded to earlier. :salute:
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but it is not the path to knowledge; it has no place in the endeavor of science."
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Re: Cruising speed rpm?

Post by jeepinocala1111 » Mon Jul 25, 2016 9:48 am

Deano wrote:
BluByU2 wrote:I cruise at, or about 2300 rpm with no headwind. Three blade 78" Whispertip, and a 1.53 Rotator.
And there is a big torque x small gear example I eluded to earlier. :salute:
I have a 2.55 reduction.

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Re: Cruising speed rpm?

Post by SWAMPHUNTER45 » Mon Jul 25, 2016 9:52 am

Yep Deano that ole 514 roller Cadillac on a 1:53 vs a sbc on a 2.55 is a great example of torque vs horsepower.

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Re: Cruising speed rpm?

Post by scottyroll » Mon Jul 25, 2016 10:25 am

I cruise @ 2800-3000 with my 2.37 box. It might go down once I get running on all 8 cylinders again and I can throw some pitch in the prop!
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Re: Cruising speed rpm?

Post by Waterthunder » Mon Jul 25, 2016 11:43 am

Of topic but all three DDs cruise between 1,200 and 1,500RPM's. They just sip the fuel I love it!
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Re: Cruising speed rpm?

Post by One Eyed Gator » Mon Jul 25, 2016 11:52 am

Jeep, your comment was basically all three blades were at different position based on the marks, Did you check with a digital level or straight on the transom or cage.

I use 1 mark as a reference then set the other to that with a digital level, stick or wire to transom or cage. When mine are tracking correctly they are never at the same pitch mark.

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Re: Cruising speed rpm?

Post by jeepinocala1111 » Mon Jul 25, 2016 12:26 pm

One Eyed Gator wrote:Jeep, your comment was basically all three blades were at different position based on the marks, Did you check with a digital level or straight on the transom or cage.

I use 1 mark as a reference then set the other to that with a digital level, stick or wire to transom or cage. When mine are tracking correctly they are never at the same pitch mark.
I will check again today but I ran a real quick check on Saturday after I went riding I could tell for dam sure it needed more pitch.

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Re: Cruising speed rpm?

Post by Des Moines Boater » Mon Jul 25, 2016 3:48 pm

I cruise at 3000 RPMs too. I just cruise around 30 mph GPS with the prop pitched on the 2 mark and I cruise 40 mph with the pitch set on the 3 mark. I have no idea what I should set the prop at but I know I have plenty of engine for more pitch. I have a 2.7 to one gear box, so, at 3000 RPMs I'm only turning the prop around 1100 rpms. I don't know if there is a right answer.
13' 6 Lazer, 383 SBC 425 hp, 2.7 Ballistic, 3 blade 80 NGR

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Re: Cruising speed rpm?

Post by PAINKILLER » Mon Jul 25, 2016 5:33 pm

I cruised at 2200 with a 2.1 no tuning to the hull had i put more pitch in the prop might have been lower
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Re: Cruising speed rpm?

Post by CarMotorBarge » Tue Jul 26, 2016 8:16 am

Deano wrote:
BluByU2 wrote:I cruise at, or about 2300 rpm with no headwind. Three blade 78" Whispertip, and a 1.53 Rotator.
And there is a big torque x small gear example I eluded to earlier. :salute:
You all need to watch out. Those EcoTurds and LS DD boats are going to out perform those high torque and low gear ratios boats and get better fuel mileage. :stirpot:

So I got 4 MPG this past weekend with my inefficient low torque motor and 2.68 ratio on a 5 seat barge. Rode to BS Hill, Bears Bluff, Jolly Gator, Loughmanns, and Lake Harney. Also ran the hill a little. Post up what fuel mileage numbers you are getting with those high torque motors and low gear ratio. The fuel mileage gives a better picture about efficiency.
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Re: Cruising speed rpm?

Post by caddy » Tue Jul 26, 2016 8:31 am

1300-1500 rpm DD caddy. Sprea dbore holley great mileage. :stirpot: :stirpot: :lol:

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Re: Cruising speed rpm?

Post by jimbo_jwc » Tue Jul 26, 2016 9:10 am

Waterthunder wrote:Of topic but all three DDs cruise between 1,200 and 1,500RPM's. They just sip the fuel I love it!
Kinda like cruising at 1200 boat loaded and to me WOT is 3000 then the Prop gets louder than mufflers .

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Re: Cruising speed rpm?

Post by OneBFC » Tue Jul 26, 2016 1:31 pm

SWAMPHUNTER45 wrote:Yep Deano that ole 514 roller Cadillac on a 1:53 vs a sbc on a 2.55 is a great example of torque vs horsepower.
Realize that both caddy and SBC setups have to make the same Horsepower to move the boat the same speed (let's ignore weight for the moment).

So it isn't really Torque vs hp.
-Russ
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The only thing stopping you is FEAR
400+hp Ecotec, 12x7.6 DBDO, 80" 3B Maximus, 2.3 OX,85+mph, water = purely optional
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Re: Cruising speed rpm?

Post by jeepinocala1111 » Tue Jul 26, 2016 2:41 pm

OneBFC wrote:
SWAMPHUNTER45 wrote:Yep Deano that ole 514 roller Cadillac on a 1:53 vs a sbc on a 2.55 is a great example of torque vs horsepower.
Realize that both caddy and SBC setups have to make the same Horsepower to move the boat the same speed (let's ignore weight for the moment).

So it isn't really Torque vs hp.
A great way to think of torque and hp is to look at a mustang and a diesel f250 Mustang has around 420hp and about the same torque f250 has 440hp with 860 torque. But the mustang with kick it ass right up till you have to pull something.

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Re: Cruising speed rpm?

Post by OneBFC » Tue Jul 26, 2016 3:06 pm

A great way to think of torque and hp is to look at a mustang and a diesel f250 Mustang has around 420hp and about the sametorque f250 has 440hp with 860 torque. But the mustang with kick it ass right up till you have to pull something.
Actually that is exactly how people get confused. They get hung up on a large torque number.

When it comes to turning a propeller, both the Mustang and the F250 you use as examples will turn nearly exactly the same propeller and produce nearly the exactly the same thrust. The ONLY differences between them is 20hp which will work out to about 60 to 80 lbs of thrust difference as well as the fact that the Mustang engine will be turning 2 to 3 times more RPM.

A 10000 lb-ft torque engine that makes 100 hp will not move your boat very well.
-Russ
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The only thing stopping you is FEAR
400+hp Ecotec, 12x7.6 DBDO, 80" 3B Maximus, 2.3 OX,85+mph, water = purely optional
Life begins at 2 BAR, Just a good ole boy

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Re: Cruising speed rpm?

Post by papasmurf » Tue Jul 26, 2016 4:24 pm

running apache hull with 400 sbc DD and cruising at 1800 rpms with no wind

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Re: Cruising speed rpm?

Post by Bdriller » Tue Jul 26, 2016 7:20 pm

well heres one yall can fuss about I have two choices on a motor, number 1 is 383 cui. 500hp 480 torque #2 choice is 400 cui. 480hp 560 torque now which one do you think is the right choice with 2.7 gear? I realise a sounder decision could be made if both dyno sheets were made available but I cant see where this is not a no brainer.

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