[frers-list]Propeller Sizing
Art Kelley
frers-list@lists.frers33.com
Thu, 26 Mar 2020 15:49:37 -0400
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I found the old posting regarding an oversized prop. Not saying it=E2=80=99s=
the right answer, just additional input.=20
Hi Bill,
=20
=20
I have a 17" Max prop on Equinox. I started out with 18 degrees and
increased it to 20 degrees as I could only get 4.5 kts at 2800 rpm. It
depends on your engine and the gear ratio of your transmission (marked on a
plate on the transmission). I would contact Fred as he is a wealth of
information and knows a lot about the maxprop. You will need the model
number of your engine as well as well as the transmission ratio. If your
gear ratio is the same as mine you likely need 2 degrees more pitch than I
do since your prop is smaller. The problem I encountered was that I had to
turn 3200 rpm to get close to 6 knots and the engine would overheat
quickly. With the 20 degree settings I get an easy 6 knots at 2700 rpms and=
she backs up like a dream and doesn't overheat. The twenty degree angle
equals about 11.5 inches of pitch.
=20
Fred Hutchison
12532 Beverly Park Rd.
Lynnwood, WA 98087
Tel: 425-355-3669
Fax: 425-355-3661
E-mail: hutch@pyiinc.com
Web: www.pyiinc.com
Regards
Rod
=20
Art
> On Mar 26, 2020, at 2:57 PM, Art Kelley <akelley@optonline.net> wrote:
>=20
> =EF=BB=BF16x10 was the original prop. Somewhere in our archives there was a=
description of someone going to a longer blade, says there is room for that=
.=20
>=20
> I fixed the problem I had last year when I couldn=E2=80=99t get full speed=
from my engine. The throttle cable finally snapped and when I put the new o=
ne on, I found the revs I had lost over the years. I am back to getting 360=
0-3800 ROM. Much cheaper than a new prop.=20
>=20
> Art
>=20
>>> On Mar 26, 2020, at 1:02 PM, Jerry Black <jcblack099@aol.com> wrote:
>>>=20
>> =EF=BB=BF
>> I have a 2 bladed max-prop feathering. 6 kts at 2,000rpm. Best thing is t=
hat when backing down you get the same thrust since the bldes rotate 180 deg=
. Also I don't have to align the shaft to insure folding. My preferred optio=
n if I have to replace.
>>=20
>> Jerry Black
>> Pelirrojas
>>=20
>>=20
>> -----Original Message-----
>> From: Brian Higgins <brian@sailingit.com>
>> To: frers-list@lists.frers33.com <frers-list@lists.frers33.com>
>> Sent: Thu, Mar 26, 2020 11:42 am
>> Subject: [frers-list]Propeller Sizing
>>=20
>> When running at 2900RPM (race clean & prepped bottom) in pretty flat (<1f=
t seas) water and light wind, I'm usually doing about 5.2-5.4kts, where it s=
eems like I should be doing at least 6kts at that RPM. Further I=E2=80=99ve=
never found where the throttle actually stops because it reaches max RPM be=
fore it runs out of power (also suggesting not enough propeller).
>> =20
>> My prop is the same Martec 16x10 two blade folding prop that at least a c=
ouple other boats have (I definitely spied on a few of your props in the boa=
tyard recently =F0=9F=98=88). Does anyone have experience going to a higher=
pitch, something like a 12=E2=80=9D opposed to the 10=E2=80=9D? Some gener=
ic calculations I looked up suggested a 13=E2=80=9D, and Gary from Martec s=
aid he too thought 10 was underpitched for the boat but suggested 12 as prob=
ably the right pitch. Before I send the prop off (it=E2=80=99s already remo=
ved for the cutlass bearing replacement), I wanted to check and see if anyon=
e has done testing and played with repitching the prop.
>> =20
>> Sent from Mail for Windows 10
>> =20
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<html><head><meta http-equiv=3D"content-type" content=3D"text/html; charset=3D=
utf-8"></head><body dir=3D"auto">I found the old posting regarding an oversi=
zed prop. Not saying it=E2=80=99s the right answer, just additional input.&n=
bsp;<div><br></div><div><p class=3D"MsoNormal" style=3D"-webkit-text-size-ad=
just: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri,=
sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-serif=
;">Hi Bill,<o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-tex=
t-size-adjust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family:=
Calibri, sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, s=
ans-serif;"> </span></p><p class=3D"MsoNormal" style=3D"-webkit-text-si=
ze-adjust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Cal=
ibri, sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-=
serif;"><o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-s=
ize-adjust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Ca=
libri, sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans=
-serif;"> </span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-=
adjust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibr=
i, sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-ser=
if;">I have a 17" Max prop on Equinox. I started out with 18 degrees a=
nd<o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-ad=
just: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri,=
sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-serif=
;">increased it to 20 degrees as I could only get 4.5 kts at 2800 rpm. =
It<o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-a=
djust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri=
, sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-seri=
f;">depends on your engine and the gear ratio of your transmission (marked o=
n a<o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-a=
djust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri=
, sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-seri=
f;">plate on the transmission). I would contact Fred as he is a wealth=
of<o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-a=
djust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri=
, sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-seri=
f;">information and knows a lot about the maxprop. You will need the m=
odel<o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-=
adjust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibr=
i, sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-ser=
if;">number of your engine as well as well as the transmission ratio. If you=
r<o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-adj=
ust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, s=
ans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-serif;"=
>gear ratio is the same as mine you likely need 2 degrees more pitch than I<=
o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-adjus=
t: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sa=
ns-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-serif;">=
do since your prop is smaller. The problem I encountered was that I ha=
d to<o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-=
adjust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibr=
i, sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-ser=
if;">turn 3200 rpm to get close to 6 knots and the engine would overhe=
at<o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-ad=
just: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri,=
sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-serif=
;">quickly. With the 20 degree settings I get an easy 6 knots at 2700 r=
pms and<o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-si=
ze-adjust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Cal=
ibri, sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-=
serif;">she backs up like a dream and doesn't overheat. The twenty deg=
ree angle<o:p></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-=
size-adjust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: C=
alibri, sans-serif;"><span style=3D"font-size: 10pt; font-family: Arial, san=
s-serif;">equals about 11.5 inches of pitch.<o:p></o:p></span></p><p class=3D=
"MsoNormal" style=3D"-webkit-text-size-adjust: auto; margin: 0in 0in 0.0001p=
t; font-size: 11pt; font-family: Calibri, sans-serif;"><span style=3D"font-s=
ize: 10pt; font-family: Arial, sans-serif;"> </span></p><p class=3D"Mso=
Normal" style=3D"-webkit-text-size-adjust: auto; margin: 0in 0in 0.0001pt; f=
ont-size: 11pt; font-family: Calibri, sans-serif;"><span style=3D"font-size:=
10pt; font-family: Arial, sans-serif;">Fred Hutchison</span></p><p class=3D=
"MsoNormal" style=3D"-webkit-text-size-adjust: auto; margin: 0in 0in 0.0001p=
t; font-size: 11pt; font-family: Calibri, sans-serif;"><span style=3D"font-s=
ize: 10pt; font-family: Arial, sans-serif;"><a href=3D"x-apple-data-detector=
s://1" dir=3D"ltr" x-apple-data-detectors=3D"true" x-apple-data-detectors-ty=
pe=3D"address" x-apple-data-detectors-result=3D"1" style=3D"color: currentco=
lor; text-decoration-color: rgba(127, 127, 127, 0.380392);">12532 Beverly Pa=
rk Rd.</a></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-adjus=
t: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sa=
ns-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-serif;">=
<a href=3D"x-apple-data-detectors://2" dir=3D"ltr" x-apple-data-detectors=3D=
"true" x-apple-data-detectors-type=3D"address" x-apple-data-detectors-result=
=3D"2" style=3D"color: currentcolor; text-decoration-color: rgba(127, 127, 1=
27, 0.380392);">Lynnwood, WA 98087</a></span></p><p class=3D"MsoNormal" styl=
e=3D"-webkit-text-size-adjust: auto; margin: 0in 0in 0.0001pt; font-size: 11=
pt; font-family: Calibri, sans-serif;"><span style=3D"font-size: 10pt; font-=
family: Arial, sans-serif;">Tel: <a href=3D"tel:425-355-3669" dir=3D"lt=
r" x-apple-data-detectors=3D"true" x-apple-data-detectors-type=3D"telephone"=
x-apple-data-detectors-result=3D"3" style=3D"color: currentcolor;">425-355-=
3669</a></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-adjust:=
auto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans=
-serif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-serif;">Fa=
x: <a href=3D"tel:425-355-3661" dir=3D"ltr" x-apple-data-detectors=3D"t=
rue" x-apple-data-detectors-type=3D"telephone" x-apple-data-detectors-result=
=3D"4" style=3D"color: currentcolor;">425-355-3661</a></span></p><p class=3D=
"MsoNormal" style=3D"-webkit-text-size-adjust: auto; margin: 0in 0in 0.0001p=
t; font-size: 11pt; font-family: Calibri, sans-serif;"><span style=3D"font-s=
ize: 10pt; font-family: Arial, sans-serif;">E-mail: <a href=3D"mailto:h=
utch@pyiinc.com" dir=3D"ltr" x-apple-data-detectors=3D"true" x-apple-data-de=
tectors-type=3D"link" x-apple-data-detectors-result=3D"5" style=3D"color: cu=
rrentcolor;">hutch@pyiinc.com</a></span></p><p class=3D"MsoNormal" style=3D"=
-webkit-text-size-adjust: auto; margin: 0in 0in 0.0001pt; font-size: 11pt; f=
ont-family: Calibri, sans-serif;"><span style=3D"font-size: 10pt; font-famil=
y: Arial, sans-serif;">Web: <a href=3D"http://www.pyiinc.com/" dir=3D"l=
tr" x-apple-data-detectors=3D"true" x-apple-data-detectors-type=3D"link" x-a=
pple-data-detectors-result=3D"6" style=3D"color: currentcolor;">www.pyiinc.c=
o</a>m</span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-adjust: a=
uto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-s=
erif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-serif;">Rega=
rds</span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-adjust: auto=
; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-seri=
f;"><span style=3D"font-size: 10pt; font-family: Arial, sans-serif;">Rod<o:p=
></o:p></span></p><p class=3D"MsoNormal" style=3D"-webkit-text-size-adjust: a=
uto; margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-s=
erif;"><span style=3D"font-size: 10pt; font-family: Arial, sans-serif;">&nbs=
p;</span></p><br><div dir=3D"ltr">Art</div><div dir=3D"ltr"><br><blockquote t=
ype=3D"cite">On Mar 26, 2020, at 2:57 PM, Art Kelley <akelley@optonline.n=
et> wrote:<br><br></blockquote></div><blockquote type=3D"cite"><div dir=3D=
"ltr">=EF=BB=BF<meta http-equiv=3D"content-type" content=3D"text/html; chars=
et=3Dutf-8">16x10 was the original prop. Somewhere in our archives there was=
a description of someone going to a longer blade, says there is room for th=
at. <div><br></div><div>I fixed the problem I had last year when I coul=
dn=E2=80=99t get full speed from my engine. The throttle cable finally snapp=
ed and when I put the new one on, I found the revs I had lost over the years=
. I am back to getting 3600-3800 ROM. Much cheaper than a new pr=
op. <br><br><div dir=3D"ltr">Art</div><div dir=3D"ltr"><br><blockquote t=
ype=3D"cite">On Mar 26, 2020, at 1:02 PM, Jerry Black <jcblack099@aol.com=
> wrote:<br><br></blockquote></div><blockquote type=3D"cite"><div dir=3D"=
ltr">=EF=BB=BF
<div style=3D"color:black;font: 10pt arial;">I have a 2 bladed max-prop feat=
hering. 6 kts at 2,000rpm. Best thing is that when backing down you ge=
t the same thrust since the bldes rotate 180 deg. Also I don't have to align=
the shaft to insure folding. My preferred option if I have to replace.
<div><br>
</div>
<div>Jerry Black</div>
<div>Pelirrojas<br>
<br>
<br>
<div style=3D"font-family:helvetica,arial;font-size:10pt;color:black">-----O=
riginal Message-----<br>
From: Brian Higgins <brian@sailingit.com><br>
To: frers-list@lists.frers33.com <frers-list@lists.frers33.com><br>
Sent: Thu, Mar 26, 2020 11:42 am<br>
Subject: [frers-list]Propeller Sizing<br>
<br>
<div id=3D"yiv2337709264">
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=20
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om:.0001pt; font-size:11.0pt; font-family:"Calibri", sans-serif;} #yiv233770=
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<div>
<div class=3D"yiv2337709264WordSection1">
<div class=3D"yiv2337709264MsoNormal">When running at 2900RPM (race clean &a=
mp; prepped bottom) in pretty flat (<1ft seas) water and light wind, I'm u=
sually doing about 5.2-5.4kts, where it seems like I should be doing at leas=
t 6kts at that RPM. Further I=E2=80=99ve never found where
the throttle actually stops because it reaches max RPM before it runs out o=
f power (also suggesting not enough propeller).</div>
=20
<div class=3D"yiv2337709264MsoNormal"> </div>
=20
<div class=3D"yiv2337709264MsoNormal">My prop is the same Martec 16x10 two b=
lade folding prop that at least a couple other boats have (I definitely spie=
d on a few of your props in the boatyard recently
<span style=3D"font-family:UI sans-serif;">=F0=9F=98=88</span>). Does a=
nyone have experience going to a higher pitch, something like a 12=E2=80=9D o=
pposed to the 10=E2=80=9D? Some generic calculations I looked up sugge=
sted a 13=E2=80=9D, and Gary from Martec said he too thought
10 was underpitched for the boat but suggested 12 as probably the right pit=
ch. Before I send the prop off (it=E2=80=99s already removed for the c=
utlass bearing replacement), I wanted to check and see if anyone has done te=
sting and played with repitching the prop.</div>
<div class=3D"yiv2337709264MsoNormal"> </div>
=20
<div class=3D"yiv2337709264MsoNormal">Sent from <a rel=3D"noopener noreferre=
r" target=3D"_blank" href=3D"https://go.microsoft.com/fwlink/?LinkId=3D55098=
6">
Mail</a> for Windows 10</div>
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</div>
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</div>
</div>
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</div></blockquote></div></div></blockquote></div></body></html>=
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