Author Topic: Korts with beckers verses steerable korts  (Read 3753 times)

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chippy

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Korts with beckers verses steerable korts
« on: July 04, 2013, 03:39:50 »
Hi fellow knowledgeable sailors.

If you had to choose between steerable Korts and fixed Korts with  Becker rudders,which would you choose and why?

I'm building an OSV and at this stage I can go either way. Length about 44 " width about 12".

I'm not interested in all out speed but manoeuvrability with some power. It will be a twin prop job of about 60 mm each.

Hope this post goes into the right place, if not please move it.

Looking forward to your replies.

Regards

Mike.
 

west coast tug

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Re: Korts with beckers verses steerable korts
« Reply #1 on: July 04, 2013, 08:05:00 »
The fixed Nozzles will tow better than the ASD.
Most of the North Sea tugs have the Nozzles and Becker's ,But they have 1 or 2 bow thrust as well.
With ASD you will not have to worry about maneuverability.
The props you can get for the nozzles will be better than the Graupner drives wheels  of the larger z Drive they have .
But if you make your own ASD pick your own props then.
The tugs here in the Fraser River most have 4 rudders no Becker's . Mine they have lots of stuff that they can hit and damage the rudders so the simple plain rudders are cheaper to fix.
Gary

Todd

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Re: Korts with beckers verses steerable korts
« Reply #2 on: July 04, 2013, 10:59:56 »
Having had fixed korts, steerable korts (both tandem and independent) and korts with rudders  I think that the only advantage kort+rudder has over the others is that there will still be the ability to steer the boat (albeit limited) when the engines are stopped.  My favourite arrangement was VP propellers with kort+rudder...I found them very effective in all weather conditions and almost instantaneous in response. (very handy to have when messing about a large oil installation in the dark  :D )
I have never used ASD of other rudderless units and often wondered if you could 'coast' into a berth etc.,without using the engines ?

Jim
« Last Edit: July 04, 2013, 11:03:26 by Todd »
Capt Jim

Puffin

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Re: Korts with beckers verses steerable korts
« Reply #3 on: July 04, 2013, 18:41:54 »
HI ; I agree will westcoast tug ,  with the fixed cort's and twin rudders . They handle bettor at the lower speeds .    PUFFIN

tugs53

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Re: Korts with beckers verses steerable korts
« Reply #4 on: July 04, 2013, 19:40:36 »
My experience with both has taught me that 'steerable' kort nozzels give you better steering in reverse.
Just like on real tugs.


We once backed the real Seaspan Chief from the company dock in N.Vancouver, across to the coal harbour fuel dock (about a mile) and through all sorts of traffic. That would have been quite a feat with a fixed nozzle.
« Last Edit: July 04, 2013, 19:43:16 by tugs53 »
MIKE

chipchase

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Re: Korts with beckers verses steerable korts
« Reply #5 on: July 05, 2013, 10:51:25 »
Hi Mike I donít think you can go far wrong with fixed korts and Becker rudders that is what I fitted to my Mearsk Leader build, I donít know if you have read the thread but here is a photo showing the setup.
Brian

chippy

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Re: Korts with beckers verses steerable korts
« Reply #6 on: July 06, 2013, 23:45:09 »
Have sent you a PM Brian.

I think I'll go with steerable Korts.....if they're not up to the job I can fix them and fit beckers at a later date.

There will be a bow thruster fitted but not enough room to fit a stern thruster, if there was it would be the Beckers form the start.

Many thanks to all who replied.

Kind regards to all.

Mike.

Norry M

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Re: Korts with beckers verses steerable korts
« Reply #7 on: July 07, 2013, 13:16:54 »
...Hi Guys...

If you are going with 2 Steerable Kort Nozzles, Might I suggest that you fit a Blade down the back of the Kort Nozzle...
I have fitted some of my Tug-Towing tugs with one blade and also with 2 blades...
This helps manouverability in both Ahead and Astern movements...

...Best Regards...Norry...
Get Yir Tugs Oot Furri Bouys

tugs53

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Re: Korts with beckers verses steerable korts
« Reply #8 on: July 07, 2013, 19:26:06 »
Good point Norry!!!!
 
I just asumed that all streerable korts had a built-on blade ;)
MIKE

PHILNZ

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Re: Korts with beckers verses steerable korts
« Reply #9 on: July 07, 2013, 20:14:20 »
I have been playing around with a steerable korts on my latest build , 24" tug model , swinging a 50mm (2") a type 4 blade prop . I welded a blade on the back (aluminum kort) . I am a believer in them now and most prob use them on every thing i build. I say this as i did a balast and operation test today with the hull and such amazing steerage in astern and forward.
Everyone for there own thou.

Regards Phil

CapnTroy

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Re: Korts with beckers verses steerable korts
« Reply #10 on: July 12, 2013, 04:42:45 »
Hard to beat the steerable Kort nozzle setup, and if you put a fishtail on the trailing edge of the nozzle blade, she'll steer that much better...

boatknut

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Re: Korts with beckers verses steerable korts
« Reply #11 on: July 23, 2013, 19:34:23 »
OK captTroy, whats a "fishtail" on the back of the blade?? please explain. I have handled tugs with both fixed and steering Kort nozzle's, prefer steering but you have me stumped on this one.
Boatknut

west coast tug

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Re: Korts with beckers verses steerable korts
« Reply #12 on: July 24, 2013, 07:18:37 »
Fish tail is the shape of the rudders water flow , Draw a simple sardine fish shape on a piece paper . I has a head and a narrow section and a tail as wide as the head. This is the shape of the top view of the rudder
What it does is it kicks the thrust farther over to the side when maneuvering  .
Even in a nozzle it will add maneuverability.
Yes it will split the thrust a bit going forward , but forward thrust is not lost .
Rudder post is 1/3 the way back from the head.
Those of you fellow's that have a Springer Tug this is your best rudder shape to use.
Gary

CapnTroy

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Re: Korts with beckers verses steerable korts
« Reply #13 on: July 28, 2013, 21:02:39 »
Yep, what Gary said, Schilling rudders have this general shape...and for the purposes of helping the steerable korts steer just a little better, a triangular wedge can be added to the back of the nozzle fin to help vector the thrust whilst turning.