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otnmbrd
 
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Default Kortz nozzle vs. prop walk



Gould 0738 wrote:
BG Nope, only two twin screw tugs with Kort nozzles.



You guyz must think I'm nutz to spell thiz with a "z" on the end.

Lotz of people do the same thing.

Wonder if the nozzle was invented by Kortz Marine Equipment company? That
company buildz equipment for fishboatz, workboatz, and general commerzial
craft.


The nozzle is a design, dating back to the 30's (in the form we now
see it) I believe and named after one of those mainly involved in the
design.
A bit of googling will come up with a number of hits including some
newer forms.
My understanding is that the nozzle removes any noticeable effect of
propwalk (feel free to read between the lines here).
On the Z-drive tug with 2 RH wheels, set the unit to 000* and put it
ahead and you have a twin screw standard boat with inboard turning
wheels (well, half of one) .... the boat should go straight ahead. It
doesn't, but immediately starts turning to stbd.
Turn the unit to (azimuth) 180* (this would be normal astern) and put
ahead and the boat should back straight. It doesn't. It immediately
starts turning (backing) to stbd ..... an indication, at least, that
there is no propwalk.

otn