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Forty Plus prop
Posted: Mon Mar 24, 2014 4:47 pm
by robhc1000
Afternoon, I will be using my new/old 1976 Forty Plus on my 3 meter Inflatable boat, now this may be daft question but if I was to use a smaller prop from a 40 minus would it give the boat more speed?
Re: Forty Plus prop
Posted: Mon Mar 24, 2014 5:24 pm
by Michael
More revs but I doubt more speed. The 40 minus prop is pretty small if I remember correctly
Re: Forty Plus prop
Posted: Mon Mar 24, 2014 5:57 pm
by robhc1000
Michael wrote:More revs but I doubt more speed. The 40 minus prop is pretty small if I remember correctly
Yes, its quite a bit smaller.
Re: Forty Plus prop
Posted: Mon Mar 24, 2014 11:38 pm
by headdownarseup
what are you up to Rob?
jon
Re: Forty Plus prop
Posted: Tue Mar 25, 2014 12:00 am
by Oyster 49
Bear in mind the differing gearbox fitted to 40 plus and forty minus engines. the forty plus has a larger prop running at lower gearbox RPM. fit the smaller prop to the forty plus and you will get less thrust and a tendency to over rev. So a slower boat and a screaming engine, revving beyond its limits.
Re: Forty Plus prop
Posted: Tue Mar 25, 2014 12:35 am
by robhc1000
headdownarseup wrote:what are you up to Rob?
jon
Hi Jon,
Just thinking aloud, had what i thought would be the answer confirmed
Hope your new project is going well.
Re: Forty Plus prop
Posted: Tue Mar 25, 2014 12:37 am
by robhc1000
Oyster 49 wrote:Bear in mind the differing gearbox fitted to 40 plus and forty minus engines. the forty plus has a larger prop running at lower gearbox RPM. fit the smaller prop to the forty plus and you will get less thrust and a tendency to over rev. So a slower boat and a screaming engine, revving beyond its limits.
Thats what I thought, stick with the origional. Many thanks.