[Public-List] Propeller Question

[Mike Lehman]

Next time I'm at my boat, I'll check the diameter and pitch. I have a
Universal M430 (30 HP) and have no speed issues. I changed the original
prop when I repowered. I'll send you a picture of the prop.

On Thu, Feb 29, 2024, 2:27 PM Sue Pilling via Public-List <
public-list at lists.alberg30.org> wrote:

> Even though I have a 25hp Westerbeke diesel, I found my Alberg would
> sometimes hardly make way against wind/waves.
> It is a three blade prop, not sure of diameter and pitch as not near boat.
> Wondered who to ask re this
> Thanks Sue. (A30 #63)
>
> > On Feb 19, 2024, at 5:18 PM, Markus Hutzler via Public-List <
> public-list at lists.alberg30.org> wrote:
> >
> > I made the conversation last year and I’m getting lower speeds. I have
> a 1:2 gear (belt) and i’m using some random prop the boat came with. This
> said, I’m not concerned about range. I just need to get in an out of the
> mooring and have some backup in emergencies.
> >
> > 10A (550W): 2.2 kn
> > 20A (1.1kW): 2.8 kn
> > 40A (2.2kW): 3.3 kn
> >
> > I will record some more numbers once the ice melts.
> >
> > Cheers, Markus
> >
> >> On Feb 4, 2024, at 16:28, Hugh McCormack via Public-List <
> public-list at lists.alberg30.org> wrote:
> >>
> >> Good day all,
> >>
> >> I know that there are some Albergs that have been converted to electric
> motor propulsion and I am contemplating this myself since the original
> inboard Graymarine has issues that are not worth fixing.
> >>
> >> In searching through the list archives I have found some useful
> information but one bit of helpful data seems to be hard to find.  This
> applies not just to Alberg conversions but to those on other manufacturers'
> boats as well.  What I am looking for is a table or graph showing the
> relationship between motor wattage draw and boat speed through the water
> and/or shaft rpm (which, with details about the prop, can be converted to
> boat speed).  Has anyone here who has converted to electric propulsion
> recorded this data for their boat under various conditions?
> >>
> >> One motor supplier gave me the following (which helps to a point but
> was derived in calm water from a "similar" boat):
> >> 3.5 knots - ~1000 watts (~20 amps)
> >> 4.5 knots - ~2000 watts (~40 amps)
> >> 5.5 knots - ~5000-6000 watts (~100-125 amps)
> >> 6 knots (hull speed) - ~12,000-15,0000 watts (~250-312 amps)
> >> Most can only provide motor data from a test bench which has no
> connection to real operating conditions with influences such as prop
> pitch/diameter/# of blades, and boat hydrodynamics when motoring into a
> headwind or in choppy seas.
> >>
> >> Having this data will help me determine optimum battery bank capacity
> which then determines bank size and associated costs.
> >>
> >> Thanks in advance if you can help.
> >>
> >> Cheers,
> >>
> >> Hugh
> >> _______________________________________________
> >> These businesses support your Association:
> >> http://www.alberg30.org/store/A30supporters.html
> >> Please support them.
> >> _______________________________________________
> >> Public-List mailing list
> >> Public-List at lists.alberg30.org
> >> http://lists.alberg30.org/listinfo.cgi/public-list-alberg30.org
> > _______________________________________________
> > These businesses support your Association:
> > http://www.alberg30.org/store/A30supporters.html
> > Please support them.
> > _______________________________________________
> > Public-List mailing list
> > Public-List at lists.alberg30.org
> > http://lists.alberg30.org/listinfo.cgi/public-list-alberg30.org
> _______________________________________________
> These businesses support your Association:
> http://www.alberg30.org/store/A30supporters.html
> Please support them.
> _______________________________________________
> Public-List mailing list
> Public-List at lists.alberg30.org
> http://lists.alberg30.org/listinfo.cgi/public-list-alberg30.org
>