Model Boat Mayhem - Forum

Mess Deck: General Section => Tugs and Towing => Topic started by: U-33 on January 24, 2017, 03:29:09 PM

Title: Idiots guide to steering nozzles...
Post by: U-33 on January 24, 2017, 03:29:09 PM
Spot of advice chaps, please..


I know naff all about steering nozzles, so I have a question for you expert types: am I correct in thinking that when using a tapered steering nozzle the narrow end is the water exit?
Title: Re: Idiots guide to steering nozzles...
Post by: ray123 on January 24, 2017, 03:58:25 PM
hi richard as per picture  'you did have it the right way around  O0


regards ray
Title: Re: Idiots guide to steering nozzles...
Post by: U-33 on January 24, 2017, 04:00:23 PM
Marvellous...thanks Ray, spot on.  :-))
Title: Re: Idiots guide to steering nozzles...
Post by: Arissara on October 24, 2017, 03:21:42 AM
The above post has been described very well.
Title: Re: Idiots guide to steering nozzles...
Post by: tugmad on October 24, 2017, 08:04:21 AM
Yes I agree ,BUT note that the nozzle is almost parallel internally, if it is too tapered you will get a water jet effect and possibly overload the motor, trying to compress the water flow outwards.
Title: Re: Idiots guide to steering nozzles...
Post by: boatsdelboy2 on February 09, 2018, 04:49:16 PM
Hi there
            I use a piece of 1/12inch plastic plumbing pipe and it seems to work very well.

Dave
Title: Re: Idiots guide to steering nozzles...
Post by: RST on February 10, 2018, 03:11:22 AM
In real life they can be tapered internally or externally depending on application and follow std. aerofoil shapes.

...I'd wager what boatsdelboy2 says is pretty much OK for the majority of model boats.  I've certainly followed similar and so long as they're roughly shaped, I would doubt anyone would notice or see too much difference.

Rich
Title: Re: Idiots guide to steering nozzles...
Post by: roycv on February 10, 2018, 08:22:48 AM
Hi I have made my own and just stay with a parallel tube.  I think the original shrouded prop was designed to reduce the wash in canals.  But the shroud does make the set up more efficient.  Then science gets involved!
Good luck anyway.
Roy
Title: Re: Idiots guide to steering nozzles...
Post by: nemesis on February 10, 2018, 05:57:52 PM
According to fishermen who have had Korts fitted, it increases thrust (great for trawling) up to 10/11 knots, after that it is as usual. nemesis
Title: Re: Idiots guide to steering nozzles...
Post by: ivorthediver on November 03, 2019, 11:16:52 AM
I have had various issues with Korts , but since purchasing them from Protech all works perfectly , as the resin ones supplied to me went oval after a few months !
Title: Re: Idiots guide to steering nozzles...
Post by: ivorthediver on November 03, 2019, 02:38:10 PM
Not wishing to tell fellow modellers how to suck eggs but having built two Kort drive tugs , one single and one double , I would like to offer some hard earned advice on Kort drive protection once installed .


I bought a ready made hull from a Tug boat supplier along with a set of 50mm steerable Kort along with all the recommended bits and bobs , but in spite of this found that one of the resin cast Ports became so oval as to be a serious problem and in need of replacement .


Further work was entailed and in the end I became distrustful of the material and asked Protean Design to assist .


They were very helpful and produced new Kort's made of aluminium and at me request fitted a pin in each of the bottoms so that I could fabricate a Skeg set up to protect the Kort base from accidental damage .
This they did at no extra charge and I made up a set of parallel arms which on a piston principal kept them aligned perfectly and I have had no further issues with the set up and regally act as the clubs recovery Tug at club meting should they require recovery to the shore line and would recommend this system to any Tug / Kort drive system model boat owners .


In addition I have recently upgraded the props to 5 blade units which work very well indeed .