Help needed to identify gearbox

[Chris35]

Can someone help me identify this gearbox?
I've been told it may be a ZF.
It is around 20 years old and is coupled to a 4 cylinder 65 Hp engine. It is in a 50 foot yacht that is around 15 tons.
The ratio has been measured at 2:1.
Any clues as to where to look for a manufacturer's plate would be helpful.

Thanks

[DougR]

Given the age, and the small amount we can see in the photo, it's probably a Hurth transmission, an HSW250a, or an HSW 450a. Hurth was bought by ZF quite some years ago, and the gears were renamed ZF 25a and ZF 45a.

The identification tag was mounted on the top of the gear case just ahead of the point where the oil lines exit the case.

To do a more comprehensive check, get dimension drawings for either Hurth or ZF gears and check the transmissions dimensions against the drawings.

DougR