Surely, Dave, I understand what you mean, my answer was indeed
![Wink ;)](http://forum.shipsim.com/Smileys/default/wink.gif)
too vague. This link to how
MAN B&W sees the question is much more
![Grin ;D](http://forum.shipsim.com/Smileys/default/grin.gif)
precise and circumstanciated. And more colored too
![Cheesy :D](http://forum.shipsim.com/Smileys/default/cheesy.gif)
.
If you wish to have an idea of how much water resistance a ship encounters, you have the choice of estimating the power used, for instance through fuel consumption for a given speed and an estimation of the propulsive efficiency, that can give you a good guess of the resistance at this speed (and under the sea conditions you mentioned, including water depth etc..) as thrust times speed is power.
![Cheesy :D](http://forum.shipsim.com/Smileys/default/cheesy.gif)
A fully wild -mad
![Angry >:(](http://forum.shipsim.com/Smileys/default/angry.gif)
- guess is that each 100 bhp of a well adapted screw propeller can deliver 1 ton thrust (or even more for tugs) on its shaft, of course only to validate your refined computations and check that you stayed in possible real world values.
![Grin ;D](http://forum.shipsim.com/Smileys/default/grin.gif)
From that, of course, initial (maximum, that is) acceleration is derived, as it is the ratio of the thrust to the ship mass.
Regards,
![Wink ;)](http://forum.shipsim.com/Smileys/default/wink.gif)
Luc