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Old 13 October 2004, 12:53   #1
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Country: UK - England
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Propellor choice for Avon 560 / Yamaha 115

Hi
I would like some advice regarding prop sizes for my boat, which is an Avon 560 Adventure RIB, with a Yamaha115 BETO outboard.

The current prop is aluminium, and has the following marks engraved on it:- IR 5280 and 13 X 19-K.

I went out today, on my own and the engine was revving to 6400, flat out at 41.5 knots.

Can anyone suggest / recommend the correct prop in order to bring the engine revs into the correct operating range?

What effect will the change of prop have on top speed, acceleration and fuel consumption. I am currently using approximately 1.3litres per mile with full tanks and usually 3 persons on board.

Thanks

Blue Lightning
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Old 13 October 2004, 14:13   #2
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Make: bombard sib
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I went for a 21 inch PROP from a 19 inch,aluminium from yamaha,reduced revs by 400rpm and gave me slightly better economy.
Great with 3 passengers,not quite so good with 5 although still OK.
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Old 13 October 2004, 14:22   #3
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Thanks. Did you stay with an aluminium propellor, or reach deep and buy a stainless one. What effect did your change of prop have on top speed?
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Old 13 October 2004, 14:27   #4
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Stayed with aluminium,the yamaha props are quite well thought of and if I hit something,I would rather wreck the prop then the gearbox.
Top speed was less in my case as it now chine rides at lower speed meaning that I cant trim up so much before chickening out.The yamaha dealer said this was due to the increase in torque.
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Old 13 October 2004, 14:30   #5
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Thanks Timboli.
Has anyone else got any thoughts / experience relating to this?
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Old 13 October 2004, 16:30   #6
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I'd also be interested in the advice of others. I've got a 90 horse suzzy on my 6m which gets to about 6,200 rpm with full fuel load and one person. I don't want to reduce top speed, but I'd like to try and get revs down a little bit.

Keith
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Old 25 October 2004, 15:34   #7
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We had a 560 last year great boat i had a 21 s/steel prop which came off a Mercury it was great for cruising , pulled about 6000rpm=40 knts but if we where 4/5 up and wanted to ski i had a yamaha 19 alloy used to make the engine over rev if you where not carefull. There is a place at Aldershot cant think of the name but they sell recon S/Steel to fit for about 70/80 pounds (cant put pound sign in )I know they advertise in the glossy boat mags
Regards Roy
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Old 26 October 2004, 12:22   #8
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Quote:
Originally Posted by Erin
I'd also be interested in the advice of others. I've got a 90 horse suzzy on my 6m which gets to about 6,200 rpm with full fuel load and one person. I don't want to reduce top speed, but I'd like to try and get revs down a little bit.
Keith.....Increase your prop pitch by 2", this will drop your top end revs and may result in slightly higher top end speed, over reving your engine will in time cause damage.
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Old 27 October 2004, 15:14   #9
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try an stainless 21

look if you can try an regular black stainless steel yamaha 21 pitch prop
slip with take off (cleaver style blades straight edges)
this prop don`t have much lift
no cupping and no ventilation

if you are looking for better fuel economy buy an yamaha pro prop 21 or 23 pitch
this props have lots bow lift and good cruising speeds
good thing you don`t need much engine trim too keep the bow up
less friction

look her for all original yamaha props that will fit your engine
http://www.yamaha-motor.com/accessor...529/All/1.aspx

if you think the yamaha props are too expensive
you can try some aftemarket props like ballistic or rapture

rapture 21 pitch is an quiet good prop
with vent holes for good acceleration
cupped for more speed
decent bowlift

ballistic is more bowlift
less acceleration
little more speed
look here http://www.miwheel.com/


nobady knows what you need .you need too try before you buy
if you can !
but a good prop will give much more performance and economie and better handeling too your boat

you have the k prop that is almost the same blade designe as the black stainless propellor
if your boat is doing good now and don`t need the extra lift buy these prop

if you have too trim your engine high too go faster then buy the yamaha pro prop

al these things are based upon my expirience
i hope you can do something with this
greetings menno from the netherlands
sorry for bad english
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