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Author Topic: Wow, how many props?  (Read 1986 times)

Brian60

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Wow, how many props?
« on: January 16, 2017, 07:14:15 PM »

So what do you think this baby is that requires so much motive power, I think I can say nobody will get it....

Brian60

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Re: Wow, how many props?
« Reply #1 on: January 16, 2017, 07:17:01 PM »

Because I'm going out and don't want to keep you all in suspense, here's the boat, called the Bucanero.  Its a fast crew boat servicing the rigs out in the Gulf....

TheLongBuild

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Re: Wow, how many props?
« Reply #2 on: January 16, 2017, 07:22:21 PM »

Beat me to it  8) ........Not.

John W E

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Re: Wow, how many props?
« Reply #3 on: January 16, 2017, 08:00:50 PM »

Nar nar nee nee nar we Geordies can go one better. Look how many props the Turbinia has.

hahahah  {-) {-) {-) {-) {-)
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tigertiger

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Re: Wow, how many props?
« Reply #4 on: January 17, 2017, 12:12:29 AM »

The question is, 'Why so many props, what is the advantage?'
Is it speed, pulling power, or both?
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derekwarner

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Re: Wow, how many props?
« Reply #5 on: January 17, 2017, 02:55:27 AM »

TT

....with the Turbinia, I understand the multiple propellers on multiple shafts was to load up the drive train in the attempt to overcome the immense cavitation that was created by the turbines high rotational speed & the as transferred high RPM of the propeller shafts

So here we would find that one propeller on each shaft on this vessel would each simply & uncontrollably cavitate  & go no where fast  O0


Derek
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Derek Warner

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tigertiger

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Re: Wow, how many props?
« Reply #6 on: January 17, 2017, 03:57:54 AM »

Got it, thanks  :-))
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furball

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Re: Wow, how many props?
« Reply #7 on: January 17, 2017, 07:05:55 AM »

Interesting... I've got a hull of what is probably a straight-runner that my father acquired in the 1930's that originally had twin shafts and two props per shaft (very much like the Turbinia), a fine pitch one on the end of the shaft, and a very coarse one further up. He thought it originally had a flash steam plant, so presumably had the multiple props for the same reason.


Lance
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derekwarner

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Re: Wow, how many props?
« Reply #8 on: January 17, 2017, 07:23:01 AM »

Yes Lance......

Incorporating multi shaft - multi propeller drives were used in harnessing the massive output of flash steam powered model vessels [many were pre radio control]   

Many of these were tethered around a pole.......still very dangerous  <*< if the cable failed .....

Derek
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Derek Warner

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TheLongBuild

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Re: Wow, how many props?
« Reply #9 on: January 17, 2017, 09:23:54 AM »


Yes Lance......

Incorporating multi shaft - multi propeller drives were used in harnessing the massive output of flash steam powered model vessels [many were pre radio control]   

Many of these were tethered around a pole.......still very dangerous  <*< if the cable failed .....

Derek


No more dangerous than those running fast electrics untethered

TomHugill

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Re: Wow, how many props?
« Reply #10 on: January 17, 2017, 12:39:00 PM »


No more dangerous than those running fast electrics untethered


Except the fast electrics are controlled and an uncontrolled tether boat isn't....
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TheLongBuild

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Re: Wow, how many props?
« Reply #11 on: January 17, 2017, 12:50:00 PM »



Except the fast electrics are controlled and an uncontrolled tether boat isn't....


Debatable at times..

John W E

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Re: Wow, how many props?
« Reply #12 on: January 17, 2017, 02:22:03 PM »

Hi there firstly - the link below is of Bob Kirtley's Pisces II - one of the fastest hydroplanes around - it did about 120 mph + - have a look at the thickness of the rope which secures the hydroplane to the centre pylon.   I would imagine the ratios of failures between the hydroplane breaking free and the high speed electric model running out of control, verges on the electric speed boat running out of control a lot more.  Also, Pisces has a single prop.

https://www.youtube.com/watch?v=ACqLSnaxrH0


Now to get back to the original topic - whilst I was at Newcastle Museum - looking at the Turbinia a few years ago - I recall there used to be side exhibits of trial models which Charles A Parsons built to experiment with various different props and prop shaft positions - to help with determining cavitation.  What made these models so interesting was they had a huge elastic band to drive the props and a huge starting handle to wind the elastic up.   I have been trying to find pictures of these on the web.

John
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