Engine upgrade

[iris]

Hi,
I am trying to upgrade my engine and have been offered a westerbeke 12/15BTBD(63hp@4000rpm) engine with a ZF BW15V transmission.
Does anyone have any information on these.
The engine has been in use for 3500 hours at half designated engine speed (1800 rpm max).
What is the ratio of the transmission and how would I go about calculating boat speed etc.

Any help would be greatly appreciated.

 

[brianrunyard]

There are a couple of links on my site to propellor calculation programs. Which will give Hull speed/planning speed dependant on type of hull, Displacement, Power, RPM, Reduction ratio etc.

Brian
http://homepage.ntlworld.com/brunyard

 

[PeterGibbs]

An engine of this size is good for a substantial vessel - 20 tonnes or thereabouts. Is this what you want and need? 4-6 HP per tonne is a good guide.

An angine offered as running only at half revs for its 3500 hr life sounds rather a tall one: was there a governor fitted or other reason why it was so under-loaded?

Some further thought seems appropriate to avoid disappointment.

PWG

 

[vyv_cox]

Transmission

ZF boxes are widely used but you will find that a range of ratios is possible. You should find a plate somewhere on the casing that gives this information, but if not it is not too difficult to measure yourself.

 

[duncan]

So are you and Figment catching any fish at the moment Brian?