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Old 07 May 2009, 03:24   #1
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Twins Or Single

Hi
Good chance of going up to a 8.5m rib in a couple of months and fancy a couple of 175 Suzukis on the back, opinions please on whether they would give the same performance as say a single 250 or a 300 and % wise how much extra fuel would they use over the single,
Thanks Mike
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Old 07 May 2009, 03:31   #2
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Fuel use, I think the suzukis are generally pretty frugal however I would imagine you would be looking at around 50 to 65% increase in fuel consumption by running twins.
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Old 07 May 2009, 07:40   #3
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Go for a single. Twins are too much weight, IMO.

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Old 07 May 2009, 07:50   #4
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I use a pair of 90s. I'd agree with suggestions on here that this setup "looses" about 25-30% overall power compared to a 180. It feels like about 130hp. Running at 3000 rpm they burn a little under 1.4l/Nm combined.

Chris's figures would suggest (if I'm using 55% more gas) that a 135Hp Etec would burn 0.9L/Nm at 3000 rpm. Someone else on here may be able to verify this?

Anyway, your 2x175hp rig should feel like 250-275hp max.
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Old 07 May 2009, 07:52   #5
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Chris's figures would suggest (if I'm using 55% more gas) that a 135Hp Etec would burn 0.9L/Nm at 3000 rpm. Someone else on here may be able to verify this?
I would say you are spot on there my old 115 etec used to run at about .9 l/nm at around 3-4000rpm.
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Old 07 May 2009, 08:03   #6
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All the above can comment much better than me regarding fuel use etc but I'd be in favour of twins as the manoeuvrability is 10 times better. My idle RIB would have twins on.
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Old 07 May 2009, 08:50   #7
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A single suzuki 300 only weighs 50kgs more. Singles are much better on fuel. Also twin engine RIBs are pretty stern heavy.

You will prob get about the same performance with 2x 175 as a single 300. Obviously safety is also a concern but you could carry a smaller aux outboard to get you home.

For the same money as the twins you could get a single Verado 350hp - that would be my choice!!!
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Old 07 May 2009, 11:41   #8
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2 strokes are my favourite.
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For the same money as the twins you could get a single Verado 350hp - that would be my choice!!!
Hmmm....

jky
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Old 07 May 2009, 12:05   #9
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Twins or single?

Twins will always use more fuel, increase servicing etc.

What twins offer you though is a sense of safety as you have two engines and as above a twin engine boat is far more manoeuvrable than a single. Twins will also give you more torque.

It depends what you want to use the boat for.

If you are in a busy area, with help nearby and in a leisure environment then a single is the way forward.
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Old 07 May 2009, 12:13   #10
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Hmmm....

jky
IF someone made a 350hp 2 stroke it would be different.

A modern version of the Evinrude V8 400hp 2 stroke would be ideal - they did one in the 1980s!!!
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