Stus-List 37+ Prop Pitch for Universal 35

Josh Muckley muckleyj at gmail.com
Sun Mar 31 06:11:30 EDT 2019


Hey Rick,

I just got the prop re-pitched and the boat launched.

https://www.pyiinc.com/downloads/max-prop/max-prop-3-blade-classic-instructions.pdf

I disassembled my prop yesterday with the intention of adding pitch.  I had
forgotten the setting at which I had left it but found the documentation
marked with 18° and tick marks by E and H.

https://www.pyiinc.com/downloads/max-prop/max-prop-3-blade-classic-instructions.pdf

Once I got blade the cup and blades off I could see E on the nose of the
cone lined up with the dimple.  Match marks before disassembly are
critical!

Further disassembly of the hub halves allowed access to the cone gear.  Be
careful not to let the cone fall out.  Removal of one half at a time
ensures that you have free hands to hold the cone in place.  Once I could
carefully control the cone and observe its orientation, I removed it.  The
mark is on the back of the gear and hard to find.  I kinda knew where to
expect it and looked carefully eventually confirming the expected setting
of H.  I found the setting of 18° = E, H

I reassembled in reverse and left it set to 20° = K, E

When we launched, I found we had increased boat speed by about 1 to 1.5
knots at ~3600 rpm and maintained 6 knots at a comfortable 2400 rpm.  I'm
pleased with the adjustments but might bump it one more step next season.

The engine is a yanmar 3HM35F (30 Hp @ 3200 rpm continuous, 32 Hp @ 3400
rpm for up to 1 hour, 35 Hp @ 3600 rpm Instantaneous) and the transmission
is a kanzaki with a ratio of 2.83

Josh Muckley
S/V Sea Hawk
1989 C&C 37+
Solomons, MD



On Mon, Jan 21, 2019, 1:29 PM Rick Rohwer <rickrohwer at gmail.com> wrote:

> Thanks for that info because that is what I want as well!  I would be
> delighted with 6.5 to 7.  It gives a guy a lot more confidence in the crazy
> currents we experience in the Puget Sound (especially up north).
>
> If the 3HM35F is running correctly the 3-blade 16” Max prop should be set
> at 20*.
>
> Thanks again for the info
>
> Rick
>
>
> On Jan 20, 2019, at 1:27 PM, Josh Muckley <muckleyj at gmail.com> wrote:
>
> Hey Rick,
>
> I responded earlier "off list" and thought you might want to see my
> thoughts.
>
> I took this off list.
>
> I have the 30hp Yanmar (3HM35F) rated at 3200rpm - continuous.
>
> It goes up to 32hp @3400rpm - 1 hour
> And 34hp @ 3600rpm - momentarily.
>
> IIRC my 3 blade 16" maxprop is set at 18°
>
> On a fresh clean bottom and clean prop I can typically get about 7.5 kts.
> It doesn't last long.  Mid season after knocking off the barnacles I get
> about 6.5 or 7.  All at full throttle.
>
> Each 2° change of pitch is supposed to affect rpm by 10%.  You should set
> the pitch so that you reach full rpm at full throttle.
>
> About 3 months ago I fixed a lingering problem with my timing cover and HP
> fuel pump.  I'm convinced that the HPFP had been "lifting" off the timing
> cover and reducing the timing.  After re-setting everything, it appears
> that the engine has considerably more more.  I know that I can push higher
> and harder.  I need to re-pitch during the haul out this spring.  I'm
> considering 1 step for a 2° reduction of about 360 rpm from full throttle.
>
> If you have any reason to suspect that your engine is not performing at
> full power, you might want to consider troubleshooting and repairing that
> before adjusting the prop.
>
> Josh
>
>
>
>
>
> On Sun, Jan 20, 2019, 3:56 PM Rick Rohwer via CnC-List <
> cnc-list at cnc-list.com wrote:
>
>> I have the same prop but a Yanmar 35.  Deep keel.  Sounds very close to
>> the same performance. I was looking to do the same tweaking on my next haul
>> out.  Looking forward to other opinions on the subject.
>>
>> I do love the difference under sail though compared to the fixed prop
>> that was on the boat since purchase.
>>
>> Rick Rohwer
>> Paikea 37+
>> Bremerton, WA
>>
>> On Jan 20, 2019, at 9:15 AM, Chuck Saur via CnC-List <
>> cnc-list at cnc-list.com> wrote:
>>
>> I have a MaxProp classic, and a Universal 35 on Daydream.  The prop pitch
>> appears very shallow, and when motoring, seems to be slow. (from memory of
>> last September, 4.5 knots@ 2300rpms)
>>
>> Any 37+ owners have this combination of prop and engine, and happen to
>> know the correct pitch for the MaxProp prop?
>>
>> And cheers from the Michigan Fridge...-12 in the UP this morning!!
>>
>>
>> *Chuck Saur*
>>
>> (517)-490-5926
>> _______________________________________________
>>
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>>
>> Thanks everyone for supporting this list with your contributions.  Each
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>>
>
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