Running a Hurth Box in Position 'B'

[ciclon1942]

Hi,

I have a Westerbeke 4-107 which is coupled up to a Hurth box, I am unsure if it is a HBW 10 or a HBW 100. I am told that the 10 is the same as the ZF12 M and that the HBW100 coresponds to the ZF 10 but I am not sure if this is correct and I know that the ZF10 and ZF12 are slightly different.

The boat is running a left hand throw prop for some reason that I can not fathom and as such is using position 'B' on the Hurth box, from what I can find out this is not for continues use and may result in more problems. I am reluctant to get a new prop as I have just bought a new ZF12M gearbox but I would like to hear other peoples thoughts on the subject.The only other thing I could think of is to get a used 18 RH 11 prop which is right for the installation but not sure if there is one about, can anyone tell me othere sizes that may fit for example we need a 18RH11 but a 16RH13 might work the same just so that it increases the chance that a used replamement may be found.

Thanks

Ross