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  #1  
Old 05-08-2008, 11:54 PM
Matt.D Matt.D is offline
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2x40 or 1x 80hp

Can anyone tell me will mounting tow 40hp outboards side by side (on a house boat 2x pontoons) give me the same thrust and top speed as one 80hp outboard? and is there any limit to how close u can mount 2 outboards togather?
Thanks Matt
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  #2  
Old 05-09-2008, 12:03 AM
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Manie B Manie B is offline
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My experience has been 2 motors is better "bite" for taking off, but less top speed = more drag.

Not too close together that you cant work on them with ease.
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Old 05-09-2008, 04:20 AM
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Pericles Pericles is offline
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The wider the spacing between the motors, the easier the manoeuvring, especially on a pontoon boat.
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Old 05-12-2008, 12:16 AM
kengrome kengrome is offline
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Quote:
Can anyone tell me will mounting tow 40hp outboards side by side (on a house boat 2x pontoons) give me the same thrust and top speed as one 80hp outboard?
I've been told that two small engines never equals the power of one large engine rated at the same total HP. In fact, one guy told me you're lucky to get 50% more from the second engine. Nevertheless, having two 40's does give you a backup engine even if they only produce the same as one 60 HP engine.
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Old 05-12-2008, 06:37 AM
northerncat northerncat is offline
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ive heard that you get 80 percent of what a single motor would give you
sean
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  #6  
Old 05-12-2008, 06:53 AM
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Pericles Pericles is offline
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Hell's teeth,

Does Fabio Buzzi know about single engines being best?

http://fbdesign.it/home.php

http://www.boatdesign.net/gallery/sh...28/limit/views

An explanation as to how the hp disappears is required. No hearsay please, scientific answers only.

Perry
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Old 05-12-2008, 06:25 PM
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Fanie Fanie is offline
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I agree with Kenneth and Northerncat. Two 60's won't give the same performance as a 115. I've had 2 x 60's on my previous boat which is the same boat I now have with one 115. The 115 with a high pitch prop performs about the same as the two 60's on bringing the boat on the plain, after that the 60's are left behing very quickly.

If the 115's prop pitch is to be dropped to a 17 or an even more radical 15 pitch for high torque, the 60's won't even come close.

The idea to use two motors instead of one is only for safety - if your one motor fails you can still get home and not drift off with the current and when you hear 'clonk !' you say is this the Nort Pole or South Pole.

This could be significant since Father Christmas is at the North Pole (I saw this movie once...). Besides .AU and .NZ I doubt there's very little else at the South Pole
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Old 05-12-2008, 06:53 PM
masalai masalai is offline
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Fanie don't forget SA and SA... (your place and further west) there is nothing between SA and Antarctica except a bit more distance to get wrecked by the winds and seas...
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Old 05-12-2008, 07:58 PM
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RHP RHP is offline
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Hence in SA all motorboats have to have twin engines (as I was told in January whilst on holiday).
Gorgeous great big Yamaha twin 225's etc...
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Old 05-12-2008, 08:08 PM
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Fanie Fanie is offline
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Only if you go out at sea. Inland waters you don't even have to have a motor at all but most guys fit one...

Masalai, they claim the 'earth' was once one continent that ceacked up and the parts drifted away from one another.

Now they claim the opposite is happening, the continents are drifting back towards one another. I wonder that the US is going to do when the philamons start robbing and plundering across the channel...
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  #11  
Old 05-12-2008, 09:20 PM
masalai masalai is offline
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rob back as they will be poor then too....
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