wave system on stern

Hi,

I have a question about the wave system at the stern.
In some books is written, that the stern wave beginns with a trough- in other books, that it starts with a crest (Saunders).
What is correct and why?

Thank you

 

Depends on the transom shape.

 

And it can be very hard to predict both its shape and position since it is the product of the whole aft section shape not just the transom transition.

Hence the stern wave is a very important observation when tank testing.

 

And fineness of the hull, speed, propulsion system, etc, etc.
See the stern wave topography for a transom stern at different speeds:
http://www.dt.navy.mil/hyd/sur-shi-mod/ste-wav-top/index.html
Cheers.