Roland, Do you know or have a way to tell us what your boat speed is and how many amps you are drawing? I would guess your hull speed is going to be somewhere around 4-5 kts. Anything faster will draw large amounts of current until the boat planes and I don't think many of us will ever get to experience that in an electric boat. I think you need to find what the sweet spot (hull speed)for your boat is and enjoy going at that speed. More pitch would get you to hull speed at a lower rpm. I think a larger pully on the motor would have a similar effect and be easier than finding a prop that fits or getting yours repitched .I did try to get my prop repitched for the same reason you want and they could not easily go any higher than a 12"pitch. I hadn't tried the boat and was speculating what I thought i would need, turns out 12" of pitch is more than I need. Both of these will tend to increase the load(amp draw) at full throttle and maybe put you over what your controller or motor are rated to do. probably best not to do that. My 16' boat for example will move quite easily up to about 4.5kts. I have a 9.25x12 prop and my real world speed to amp ratio is something like this. 20amps@48V=3.5-4kts, 35amps=4.5kts, 50amps=5kts, 85amps(max constant draw for etek ?)=5.2 kts ,125 amps( max for my controller)=5.6kts 160 amps= 6kts, full throttle 180amps =6.2kts. I have to be careful not to run too fast. If anyone else was going to be using the boat I would size the prop so my draw at full throttle was under 125 amps.or maybe put a stop on the joystick. I like being able to move along at a low rpm and I find that I do use the momentary burst of power option . Hope that is helpful.
--- In electricboats@yahoogroups.com, "babschaaf" <martine_roland@...> wrote:
>
> Hello electricboaters,
>
> I Own a litle electric boat, see attachment. http://www.electraboat.com/
>
> As you can see (click at more pictures) it has a 8.2: x 12 pitch prop.
>
> I replaced the electric motor with this one.
>
> http://www.astrosyn.com/shopimages/technicaldatasheets/Industrial%20Motors%20Technical%20Datasheet.pdf
>
> Type:A140 PLMW11 Bekr: PM Isol.KL: F
> U: 24V DC N: 1100min-1 Nr.: 2501
> I : 60 A IP: 42
> P: 1100 W ID: S2-30 VDE530/84
>
> I have on this motor a 100 mm diameter pulley with a belt to the propshaftaxle which has a 130 mm pulley. Now, I've experimented a bit with the best combination of pulley with this motor. Is there a way that you can calculate the best ratio for this?
>
> Of cource i realize that increasing the diameter of the prop would help, but obvious there's isn't enough room.
>
> I'm looking for a bit more speed as it seems that I even don't reach hull spead. Can this be done by altering the prop pitch=
> Can someone give me tips om how to get speed up? I have a potmeter to control the speed of the boat. I dont want to boat on full power all the time but if I need it, I'd like to have some more umph when needed. I live at a streaming river, not that fast, but enough.
>
> I'm not an electrician but trying to be as auto didactive as I can. Everyone I ask doesn't seem to understand really what I'm talking about. The only advice I get: bigger motor, or more batteries, but as I undertand that is not the thing or solution. So anyone of this good group with advice would be appreciated. I think you guys and girls should know and could lead me in the right direction.
>
> I also looked at the propellors from Torqeedo, but these seem to have a different way of attachment tot the prop axle.
>
> Thanks in advance,
>
> Roland Kruijer
> The Netherlands
>
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