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 2 engines on a boat????
#1645651
10/04/07 12:24 AM
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Joined: Jul 2007
Posts: 13,435
Rick Paradis
OP
Sausage King
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OP
Sausage King
Joined: Jul 2007
Posts: 13,435 |
Ok guys, I will probably get slammed for this question but I am going to ask it anyways....
I saw the post about the 89 mph pontoon boat...
My question is, if you put two motors on a boat, that are the same horsepower, will it in fact make the boat go faster?
I was thinking that since the motors are the same size, that they will not turn anymore rpm's then the other, so in turn just go the same speed.
I was thinking that the only reason people put 2 motors on their boats is mainly because when they get out away from shore, mainly saltwater, that is one broke down they could get back in, plus have the added thrust to get through the larger wake....
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Re: 2 engines on a boat????
[Re: Rick Paradis]
#1645968
10/04/07 02:32 AM
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Joined: Mar 2005
Posts: 1,621
psycho0819
Extreme Angler
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Extreme Angler
Joined: Mar 2005
Posts: 1,621 |
I'm no physicist, obviously. But.... In my way of thinking about it, if the boat were too long/heavy the motor would never be able to achieve max rpm. Thus adding the extra motor puts the weight to thrust ratio closer to where it needs to be. But this would obviously only be achieved from turning more rpm.
Then there are prop pitches to consider. With all the extra thrust, running "top end props" seems a better way to go w/two motors, since the torque is there to get up on plane. They'd move more water that way, thus higher mph at a given rpm compared to the optimal pitch for a one motor set-up.
Just my 2 cents. I'm sure someone more knowledgeable than myself can delve a little deeper.
Jay
If you're not living on the edge, you're taking up too much space!
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Re: 2 engines on a boat????
[Re: psycho0819]
#1646009
10/04/07 03:04 AM
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Joined: Dec 2005
Posts: 2,678
Hail Boy
Extreme Angler
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Extreme Angler
Joined: Dec 2005
Posts: 2,678 |
whoops
Last edited by South Padre Bum; 10/04/07 03:12 AM.
Wooo!
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Re: 2 engines on a boat????
[Re: Hail Boy]
#1646267
10/04/07 11:40 AM
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Joined: Apr 2007
Posts: 1,984
Michial Thompson
Extreme Angler
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Extreme Angler
Joined: Apr 2007
Posts: 1,984 |
It was my understanding that when you went to two motors, you would also be going to higher pitched props to keep the RPM's down to where they should be.
You would gain speed, but it wouldn't be twice the speed, you would probably gain 20-30 percent at most. This is where physics comes into play. The faster you go the more drag the water puts on the boat. The drag to speed ratio isn't an even 1:1 ratio drag increase lots more.
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Re: 2 engines on a boat????
[Re: Michial Thompson]
#1646281
10/04/07 11:45 AM
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Joined: May 2007
Posts: 743
BIG OLE BOBBERS
Pro Angler
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Pro Angler
Joined: May 2007
Posts: 743 |
The question was "will the boat go faster with two engines".
The answer is obviously YES, faster but of course not twice as fast, common sense. How much faster......tons of variables, let's leave it at that.
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Re: 2 engines on a boat????
[Re: BIG OLE BOBBERS]
#1659293
10/10/07 01:14 PM
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Joined: May 2003
Posts: 12,334
PGR Mike
TFF Guru
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TFF Guru
Joined: May 2003
Posts: 12,334 |
If you put a plane on a conveyor belt will it be able to take off?
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Re: 2 engines on a boat????
[Re: PGR Mike]
#1659341
10/10/07 01:41 PM
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Joined: Oct 2004
Posts: 22,407
R T
TFF Guru
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TFF Guru
Joined: Oct 2004
Posts: 22,407 |
If you put a plane on a conveyor belt will it be able to take off?
:ROLFMAO:
It doesn't matter how you find the pot of gold, all that matters is that you beat the leprachaun.
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Re: 2 engines on a boat????
[Re: R T]
#1659443
10/10/07 02:29 PM
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Joined: Sep 2005
Posts: 28,109
Uncle Zeek
aka "Mom"
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aka "Mom"
Joined: Sep 2005
Posts: 28,109 |
Didn't you have this as a thread once already? Could've sworn I'd read this about a week or two ago
"Decency is not news; it is buried in the obituaries --but it is a force stronger than crime" ~ Robert A. Heinlein
Artim Law Firm, PLLC
Estate planning & tax attorney AND 07/02 FFL
2250 Morriss Road, Suite 205, Flower Mound, Texas 75028
972-746-0758 mobile
zac@artimlegal.com
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Re: 2 engines on a boat????
[Re: Uncle Zeek]
#1659542
10/10/07 03:03 PM
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Joined: Oct 2007
Posts: 25
D_G
Outdoorsman
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Outdoorsman
Joined: Oct 2007
Posts: 25 |
this thread is from a week ago
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Re: 2 engines on a boat????
[Re: BIG OLE BOBBERS]
#1660101
10/10/07 06:35 PM
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Joined: Jun 2006
Posts: 50,176
TreeBass
Lt. Dan
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Lt. Dan
Joined: Jun 2006
Posts: 50,176 |
The question was "will the boat go faster with two engines".
The answer is obviously YES, faster but of course not twice as fast, common sense. How much faster......tons of variables, let's leave it at that. I'd go with this answer 
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Re: 2 engines on a boat????
[Re: TreeBass]
#1663501
10/12/07 12:37 AM
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Joined: Jan 2005
Posts: 21,821
Pat Goff
TFF Guru
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TFF Guru
Joined: Jan 2005
Posts: 21,821 |
Here's an example..
When I was with champion they hung twins on a couple of 22' bass boats, with a single 200 it was maybe 60 mph, with twin 200's, it pushed 85.
Same boat with twin 225's was really close to 100.
not quite twice the speed, but substantial.
Pat Goff Seadrift TX ![[Linked Image]](https://i.ibb.co/X48Kbbq/scooter-shallow.jpg)
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Re: 2 engines on a boat????
[Re: Pat Goff]
#1676511
10/18/07 02:09 AM
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Joined: Feb 2007
Posts: 508
SpecialK
Pro Angler
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Pro Angler
Joined: Feb 2007
Posts: 508 |
its sounded to me like the original question was, if the two motors matched to ,the one motors horsepower not if you double the horses. If you double the horses you are going to have many more options with prop pitches than if you have the same amount or HP in motors equaling a single..
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Re: 2 engines on a boat????
[Re: SpecialK]
#1677200
10/18/07 01:34 PM
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Joined: Apr 2007
Posts: 1,984
Michial Thompson
Extreme Angler
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Extreme Angler
Joined: Apr 2007
Posts: 1,984 |
SpecialK;
I missed that in the original question, but when I re-read the question I see what he was asking now.
I've been curious about that answer myself. I have a CC w/ single 120 which is marginally powered. I spend enough time off shore that I am considering putting a kicker motor on it, but the thought had crossed my mind to re-power to twin 75's or 90's.
I doubt the answer is as simple as two 60's equalling a single 120 for performance, but perhaps two 60's might work out to a net of 100hp or something like that...
I'm interested in hearing other people's ideas on this one?
Also if a transom isn't designed for two motors, is the solution to replace the transom, or is there a bracket/motor mount that would move the motors back away from the transom allowing two of them to be side by side?
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Re: 2 engines on a boat????
[Re: Michial Thompson]
#1677751
10/18/07 04:31 PM
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Joined: Nov 2006
Posts: 3,711
lure buddy
TFF Team Angler
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TFF Team Angler
Joined: Nov 2006
Posts: 3,711 |
I remember that Champion with the twins man it was something else. I will have to see if I can find some pics of it. They actually made two of them if I am not mistaken. When I was working for Nickols Marine we had it at the Tulsa boat show on display.
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Re: 2 engines on a boat????
[Re: Michial Thompson]
#1678086
10/18/07 07:00 PM
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Joined: Feb 2007
Posts: 508
SpecialK
Pro Angler
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Pro Angler
Joined: Feb 2007
Posts: 508 |
SpecialK;
I missed that in the original question, but when I re-read the question I see what he was asking now.
I've been curious about that answer myself. I have a CC w/ single 120 which is marginally powered. I spend enough time off shore that I am considering putting a kicker motor on it, but the thought had crossed my mind to re-power to twin 75's or 90's.
I doubt the answer is as simple as two 60's equalling a single 120 for performance, but perhaps two 60's might work out to a net of 100hp or something like that...
I'm interested in hearing other people's ideas on this one?
Also if a transom isn't designed for two motors, is the solution to replace the transom, or is there a bracket/motor mount that would move the motors back away from the transom allowing two of them to be side by side? I saw a bracket that was made to rig 2 outboards in a singles place. I cant remember what brand it was but it bolted in the center factory holes and then on either side. On the other note. With two motors and 2 props(ie 2 60hp's) you have more traction to get up on plane. Thus you can put high pitch props on for more speed. The guys at Nettles props here in Austin have told me that you can gain about 15% top end if you do this. IMO that my be pushing it a little but I can definately see how it "could" go faster. I think the variables in hull design are a big factor also.
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