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Old 14 May 2014, 16:59   #1
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Propping question

My twin Mariners 60s are currently running 13.75x17 Solas ally props, running with just myself on board it tops out at 5200rpm but I feel it lacks some sharpness on the throttle. Cruising this weekend it sat happy at exactly 4000rpm doing 23knts, I would just like that little more "poke". I also felt that manoeuvring at idle speeds was a little numb.

I'm toying with the idea of going to 15" props, these bigfoot engines actually come with a 15" prop as standard, would it have 17" props on it because its a twin setup? Do the same prop rules apply with twins as they do for singles?

Your thoughts?
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Old 14 May 2014, 17:17   #2
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If you are topping out at 5200 you are probably over propped. This like driving in too high a gear and not good for your motors. What the motor comes with is irrelevant. It depends on the set up, the hull, weight and usage.

You need to check the height of the motors is correct (especially as you are dragging two gear cases through the water)

http://www.veradoclub.com/smf/index.php?topic=137.0

Then start changing props, that said 15s will get you another 2-400 rpm and will liven the boat up for holeshot and might even increase your top end

Good luck
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Old 14 May 2014, 17:36   #3
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Quote:
Originally Posted by Oscarguitar View Post
If you are topping out at 5200 you are probably over propped. This like driving in too high a gear and not good for your motors. What the motor comes with is irrelevant. It depends on the set up, the hull, weight and usage.

You need to check the height of the motors is correct (especially as you are dragging two gear cases through the water)

Propping correctly & how to test props.....

Then start changing props, that said 15s will get you another 2-400 rpm and will liven the boat up for holeshot and might even increase your top end

Good luck
wot he said!

Smaller props improve low speed manoeuvring & make the boat more responsive. I originally had 21" props on mine & it handled like a barge, 19" 4 bladers transformed it.
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Old 14 May 2014, 17:38   #4
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It's looking like I might be spending fuel money on props instead.
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Old 14 May 2014, 17:51   #5
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It's looking like I might be spending fuel money on props instead.
If you can stretch to Stainless props you'll pick up around 200rpm for the same pitch ally, get yer hand in your pocket man
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Old 14 May 2014, 17:52   #6
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Propping question

Quote:
Originally Posted by Pikey Dave View Post
If you can stretch to Stainless props you'll pick up around 200rpm for the same pitch ally, get yer hand in your pocket man
Oooof!

My Scottish arms are too short for these damn pockets.
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Old 14 May 2014, 19:40   #7
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Check what's the max wot rpm factory specified for that engine, will know how much under or over propped you are.

Happy Boating
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