I have the same HM35F with 3 blade prop max rpm's 2400 on unproven tachometer .
I think I might be over propped but will dig into the issue further on next
haul out
I spend a lot of time @2000_2200 approaching 6kts (5.6_5.8 kt on boat speed and
6-6.2 kt on GPS). I might get 7 kt if I floored it on flat sea with no
headwind. I don’t run it that hard unless I am in trouble.
Rick
Paikea
37+/40
From: cnc-list@cnc-list.com
Sent: Wednesday, July 22, 2015 4:20 PM
To: cnc-list@cnc-list.com
Cc: Martin DeYoung
>…2 bladed prop is really that inefficient or my pitch should be changed.<
My experience on OPB (other people’s boats) with 2 bladed MAX props is they are
not inefficient. Calypso has a 3 blade mostly to reduce vibration. If I had
to replace the prop I would buy a 2 blade MAX prop.
> Above that rpm, there is not much of a noticeable change in speed, just
> noise.<
Does this indicate you can throttle up to max engine rpm easily? If so I would
take that as an indication the pitch should be increased.
Last time I changed the pitch on Calypso’s 3 blade it seemed I could move in
+-10% change increments. Do you have a local boat yard that would give you a
deal on a quick haul out, hang in the slings to change the pitch, the re-launch
to test? I have read of people changing the pitch in the water but I would not
attempt it myself. Maybe a pro dive service has the chops and spare parts to
pull it off in shallow water clear enough to find the important piece that
dropped to the bottom.
Martin DeYoung
Calypso
1971 C&C 43
Seattle
Description: Description: cid:D1BF9853-22F7-47FB-86F2-4115CE0BAF2F
From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Ron Ricci
via CnC-List
Sent: Wednesday, July 22, 2015 6:07 AM
To: cnc-list@cnc-list.com
Cc: Ron Ricci
Subject: Stus-List C&C 37+ Propeller & Boat Speed
I’m curious to see what kind of speed everyone gets on their 37/40. It is
interesting to see that some listers get over 7 knots. I’m lucky to get 5
knots at 2500 rpm. Above that rpm, there is not much of a noticeable change in
speed, just noise.
Here’s what Patriot has:
· 3HM35F Yanmar 30 HP
· 2.14 Gear Ratio
· 16” Max-Prop – 2 bladed
· Right Rotation – from
http://www.pyiinc.com/images/pdf/max-prop/PYI_Max-Prop_2_Blade_Instructions.pdf
o 18°
o X = E
o Y (dot) = H
o Y (dot)(dot) = V
Perhaps the 2 bladed prop is really that inefficient or my pitch should be
changed. Any advice will be appreciated.
Regards,
Ron
Ronald V. Ricci
S/V Patriot
C&C 37+
Bristol, RI
ron.ri...@1968.usna.com
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