Yeah, the clearance is fine for up to a 15" prop.
I have about 8-1/4" from strut to hull which allows for a radius of
14-3/4", giving a 15% allowance.
If I went with the Kiwiprop, I would have replaced the blades with a
smaller set giving a 14.5" diameter.
However, I have decided to go with the fixed 12x14 prop.
Upon reflection, there were just too many elements (and vendors)
involved with fitting the kiwiprop to my boat:
- the prop seller
- new blade set from kiwiprops.com
- prop reducer bushing from Tacoma Propeller
- custom prop nut from a local machine shop.
After currency conversions and shipping, even if the prop seller were to
*give* me the kiwiprop, I would still have over $500 to put into
adapting a prop to my boat. The 12x14 prop that fits directly to my
7/8" shaft comes in around there and doesn't require anything exotic to
be machined to fit it.
To offset the performance hit, I'll just have to do some
"electro-feathering". I wish the controllers could integrate instrument
data, such as STW in order to spin the prop at the speed of the water
column. I know it is possible to spin the prop at a very low current
but in very light winds, that may actually produce a little bit of
thrust and would be extremely frowned upon by racing organizations...
Anyway, this is diverging from my original question as to prop choice,
and my prop choice has been made so anything further is just useless
rambling on my part :-)
Cheers,
/Jason
On 2014-02-27 08:58, Doug+Gina wrote:
> Jason,
> suggest you double-check clearances as Eric suggested.
> According to Dave Gerr you should have at least 8-10% of prop
> diameter as clearance with 15-20% recommended. This minimum
> varies with RPM. The primary reason for the additional clearance is
> to
> minimize vibration of blade tips
> Doug
>
--
Jason Taylor
--
S/V Fugu
1978 Beneteau First 30
Electroprop PM-20
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