propeller - Forum

nissim
Member Topic Starter

2011-06-03T21:56:43Z

good day everyone!
I have a "seal 28" and I need your help in choosing the size of 3 blades propeller for her
Nanny engine 21 hp zf10m 2:1 ratio transmission 1"shaft
thank you very much
nissim

Mike Edwards
Advanced Member

2011-06-03T22:20:30Z

#2

Hello Nissim
Aztec, Seal 28 nr. 26 has a Beta 20 3 cylinder engine and I have a 13 x 9, 3 blade prop. The engine revs to 3600rpm max.
This arrangement gives me just under 7 knots in calm conditions, good stopping power and drive in rough seas.
If you PM me with your email address I can send you a propeller calculator spreadsheet.

Mike

Mike Edwards
Seal 28 "Aztec"

Mike Edwards
Seal 28 "Aztec"

nissim
Member Topic Starter

2011-06-04T12:13:39Z

#3

Thank you very much for your replay Mike
It seams we have the same engine preforms
My question is do the engine rich 3600 rpm
and if the answer is yes do you have black smoke or the water that are coming from the egzoze are black when you run in 3600 rpm
my Email is nissim94@gmail.com
Tank you again
Nissim

Mike Edwards
Advanced Member

2011-06-04T20:41:59Z

#4

email sent with Propking spreadsheet attached

Mike Edwards
Seal 28 "Aztec"

Mike Edwards
Seal 28 "Aztec"

nissim
Member Topic Starter

2011-06-05T18:14:03Z

#5

Hello Mike!
I received your Email with the attached it is very useful.
Thank you for it.
I have looked on the 20 Beta marine engine details, this engine is based on kubota and my Nanny engine is based on the same kubota.
Both have almost the same specifications.
If you have the same ratio 2:1 transmission I can take the same propeller without worrying from any trouble.
If it is right in your opinion I will do it.
thank you very much
nissim
Via Mares

Mike Edwards
Advanced Member

2011-06-21T21:50:06Z

#6

Sorry are you waiting for a reply, My gearbox is a Technodrive TMC40M 2:1 ratio.
Mike

Mike Edwards
Seal 28 "Aztec"

Mike Edwards
Seal 28 "Aztec"

nissim
Member Topic Starter

2011-06-28T20:49:24Z

#7

Thank you very much Mike!
I am looking for this size of prop.
I hope to find one soon.
Nissim.

Mike Edwards
Advanced Member

2011-06-28T21:58:26Z

#8

My prop is a Vetus, a P3B I think.
http://viewer.zmags.com/...on/dde28f6a#/dde28f6a/40

Mike Edwards
Seal 28 "Aztec"

Mike Edwards
Seal 28 "Aztec"

nissim
Member Topic Starter

2012-01-19T10:32:12Z

#9

Hello again
I found 3 blade 14"/9" propeller
What is your opinion:
To use it as is or to make it smaller 13"/9"
Thank you
Nissim
Seal 28 "Via Maris"

Mike Edwards
Advanced Member

2012-01-19T19:22:57Z

#10

Hi Nissim
I am not expert on this subject but I think your engine will be revving just a little bit slower.
I would suggest it is near enough to try as it is for a season and if the engine is not reaching high enough revs on full power have it reduced a little.
I was once told that an inch on the pitch or diameter is equivalent to 200 RPM.
good luck

Mike Edwards
Seal 28 "Aztec"

Mike Edwards
Seal 28 "Aztec"

nissim
Member Topic Starter

2012-01-19T22:38:30Z

#11

Thank you for your quick answer Mike
I am new in the field and your feedback is very useful for me
thank you again
Nissim
SEAL 28 "VIA MARIS"

Neil Sinclair
Advanced Member

2012-01-20T12:52:52Z

#12

If you found your 14 x 9 prop overloaded the engine - you could trim the blades to the size you want. The propellor would be slightly less efficient than one made to the correct dimensions but I don't think you'd notice. I have done this in the past with acceptable results! A hack-saw and file is all you need.

Neil Sinclair
Seal 28/27
'Andiamo of Exe'

Neil Sinclair
Seal 28/27
'Andiamo of Exe'

nissim
Member Topic Starter

2012-01-20T14:58:07Z

#13

Thank you Neil
We have here in Haifa a professional men that do this work
I do not think i can handle such a work
Anyway I believe that I am in the right way to solve my propeller problem
Many thanks
Nissim
Seal 28
"Via maris"

nissim
Member Topic Starter

2012-10-06T10:32:20Z

#14

Hi again
At last I found the solution to my propeller problem
After I replaced the propeller to 14/9 it steel did not go more then 1500 rpm
So I looked for the solution in another place and found it in the exhaust elbow,where the gases from the engine meat the sea water, it was closed with soot and blocked the way out of the exhaust gases.
I replaced the elbow ,now the engine go up to 3400 rpm and the speed is (+-)6 knots
thank you all for your answers
Nissim
Seal 28
"Via Maris"