Big Prop vs Little Prop

[codhw]

advice and guidance from the experts would be much appreciated. I have an Enfield 130 Z drive pushing my 23ft boat the trouble is I cant get above 1800 revs, subsequently Im only getting between 6 to 8 knotts. Ive been told to downsize the prop as its not the engine size causing the propblem. My boat currently has a 11inch prop on it Ive been told if I down size the prop that this would increase the revs and perhaps get her backside up out of the water and increase her speed. This mail is two questions really 1 do you agree with the advice? 2 anyone know where I can get hold of a smaller prop for and enfield 130 z drive? (ive been looking on ebay with no success).

[mark]

advice and guidance from the experts would be much appreciated. I have an Enfield 130 Z drive pushing my 23ft boat the trouble is I cant get above 1800 revs, subsequently Im only getting between 6 to 8 knotts. Ive been told to downsize the prop as its not the engine size causing the propblem. My boat currently has a 11inch prop on it Ive been told if I down size the prop that this would increase the revs and perhaps get her backside up out of the water and increase her speed. This mail is two questions really 1 do you agree with the advice? 2 anyone know where I can get hold of a smaller prop for and enfield 130 z drive? (ive been looking on ebay with no success).

might be the prop pitch rather than the diameter, 11" is quite a small prop but it might have a very steep pitch

to work it out accurately, need to know max revs the engine is rated for, the gearbox ratio and the HP of the motor

as a general rule of thumb
every extra inch of pitch cuts engine revs by about 225rpm and every inch of diameter looses about 200rpm

a bigger prop delivers more torque, so a bigger prop with less pitch is better

without knowing any more details I'd say a 13" prop, maybe 15" pitch, but need more info

plenty place that sell props, but they ain't cheap, but is an investement that will pay itself back quickly as yopur probably burning more fuel than you need to as well, so propped right you'll go faster and burn less

what boat is it as well?? hull shape can make a huge difference,

[boblydon]

i am sure i have 2, will check out the size of them later on...sure i have spares for your outdrive aswell

[boblydon]

sorry for the delay in replying, just got back from watching the darts at the marina....i have 2 12x11 props and 2 13x11 props, your more welcome to try them to see if it makes any difference to your boat, also have some doel fins

[boblydon]

meant arena !!!

[Charlie_Thompson]

Big Prop Little Prop - CARD BOARD BOX


Sorry I am trying to learn about this type of caper

[mark]

my money is on 13 x 11

[mark]

or the 12 by 11

[codhw]

Thanks all for the advice its really appreciated. boblydon could I get back to you with your kind offer as I will need to check what props we have already tried. Once again lads thanks alot.

[5150]

Big Prop Little Prop - CARD BOARD BOX
Sorry I am trying to learn about this type of caper

YouTube - Bob The Builder - Big Fish, Little Fish...Upload your dance video for a chance to be on Bob's DVD!

Odd one I found - if you mute the video and play Hearts Barracuda, the timing of their dancing is near perfect to go along with the song. Don't ask me how I discovered this.

[codhw]

Hi bob I have sent you a pm

[boblydon]

read it yesterday and was going to reply, but then started reading a different thread and forgot, you can try them as soon as you like, either collect from royal quays or wallsend whenever is good for you

bob

[codhw]

hi bob I could come across this Saturday around 12ish how do I contact you? if you could ring me on my mobile we could sort the time etc

[boblydon]

pm sent