DSK the marine propulsion expert wrote:
In any case, the ship was going full speed, the loss of the prop
stream across the rudder would not reduce the rudder's effectiveness
very much.



Nav wrote:
http://www.dellamente.com/titanic/engines5.htm

Interesting web site. Thanks for the link.

It does contain a number of inaccuracies, though.


"Regardless, most scenarios agree steam to the turbine would have been
cut off. While this had little effect on the ship's forward motion,

???

The central turbine was about 35% ~ 40% of the ships forward power. How
is it going to have "little effect on the ship's forward motion?"

Or do they mean that shutting off steam to the turbine would not have
produced significant stopping impulse? That would be much more correct.

They also don't appear to know how the reciprocating engines were reversed.


... it
deprived the rudder of the steady, forceful stream of water necessary to
turn a ship of that size.

???

A steady stream of water goin 22 + knots is not "forceful"?


... Several sources claim the rudder on the
Titanic and her sister ships was too small. If that was indeed the case,
shutting down the center turbine would be the last thing you would want
to do in an emergency."

The "rudder too small" claim is total malarkey. The Olympic was the same
design and had a long service career, with a reputation of being a good
handling ship.


Hmm, seems to agree with me?

Sure. It's incorrect and based on assumptions when accurate data is
readily available.

Speaking of which, have you worked out the prop slip for the Olympic
class ships yet? Data readily available, all you need is the prop pitch,
top speed, and top speed rpm.

... My yacht steers well without propwash
because it's rudder, in comparison, is huge... My point is that, most
power vessels can have much smaller rudders because they use the
propwash to significantly increase rudder effectiveness. It's standard
naval architecture.

At low speed, sure. At full speed, the prop stream does increase rudder
effectiveness but I'd say that it's not "significant." Judgement call, I
guess... certainly your vast experience in handling large steam ships
and your claimed naval architect training give you a big advantage here.

DSK