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Fra: AJSaniez  
Sendt: 22. oktober 2007 18:20
Til: info@flexofold.com
Emne: Propeller size

Dear Sir,

I recently purchased a Hanse 430 which is equipped with a Yanmar 54 hp 
and a 18X12 3 blades Flex o Fold propeller. I have already logged 2500 
NM including 270hours engine 

I found the propeller size too short: 2000 rev gives 6.3 knt. The same 
boat with the same engine and a gori prop gives 7.3 knt.
I would like to know if it is possible to change the blades and fit the 
propeller with a greater pitch? And at what price?

Alain Saniez

Dear Sir
This is a common discussion which need some comments regarding overloading a
modern diesel engine, pollution and engine warranty.
Many boat owners want to cruse at low rpm, and they really never attempt to
utilize the maximum performance from the engine. In other words, they do not
overload the engine under these circumstances, but the risc exist and that
is the problem.

The same boat as yours with a Gori and 7.3 knots at 2000 rpm will most
probably not be able to reach its rated rpm 3.000 + 5%, without overheating
and carbonizing. If the engine breaks down for some reasons within the
warranty period, the engine manufacturer will claim that the problem is
caused by a propeller being too large. As a consequence from that, they will
also be reluctant to accept a warranty claim.

According to Yanmar, a propellersize is approved if the hull speed is
achieved at max rpm + 5% and I know that Hanse and Yanmar have decided to
specify the 3 blade 18x12 for that reason.
Believe me, it is easy for us to achieve 7.3 knots or more at 2.000 rpm. You
could get a new bladeset 18x13-3L or 18x14-3L. The price is 1.100 Euro incl
VAT.
The question is if you are prepared to change within the warranty period. I
doubt that Yanmar will approve the Gori if the warranty is still valid.

Best regards
Jack Skrydstrup
 
Flexofold Propellers
Tel +45 7555 4346
Fax +45 7555 4366
www.flexofold.com