Model Boat Mayhem - Forum

Technical, Techniques, Hints, and Tips => Engineering Techniques and Materials. => Topic started by: tizdaz on January 05, 2018, 08:45:49 PM

Title: Rudder Tube?
Post by: tizdaz on January 05, 2018, 08:45:49 PM
Hi guys,


Whats best method for the rudder tube, (outer tube) to go through the hull, needs to be water tight for obvious reasons! my inner shaft is 4mm, so am I best just getting some brass tubing with 4mm ID & grease it or ?


Cheers
Title: Re: Rudder Tube?
Post by: Tug-Kenny on January 05, 2018, 09:03:02 PM

I always fit the rudder tubes and seal them with epoxy, on the inside of the hull.

ken
Title: Re: Rudder Tube?
Post by: tizdaz on January 05, 2018, 09:20:09 PM
yeh think I'm going to use some P40 to bond it inside the hull, but just not sure what to use for the actual tubing, I've sent MMM an email as they offer custom size prop tubes & I'm thinking a prob tube would be ideal, I only need it to be 50mm length with an ID of 4mm so see what they say, what do you guys use for the tubing?
Title: Re: Rudder Tube?
Post by: Tug-Kenny on January 05, 2018, 09:30:27 PM
I use brass tube from B&Q.  Have the rudder shaft in your pocket for sizing up at the store.  It doesn't have to be a tight fit as it lives above the water line at the top.  ok2

ken
Title: Re: Rudder Tube?
Post by: tizdaz on January 05, 2018, 09:38:02 PM
hey :)


I was thinking about that, but just thinking if the wall would be too thin as the stuff at my B&Q has a very thin wall (my build is a 1/12 TID) & the rudder is pretty large & going to be made out of brass, you think it would be ok to use the stuff from B&Q for my rudder or would i be better off with prop tubing which has bushings & thicker wall ?
Title: Re: Rudder Tube?
Post by: chas on January 05, 2018, 11:48:44 PM
If you want to strengthen the tube, either sleeve it in another length of tube and solder them, or drill a piece of hard wood and encase the tube in that.
  Both have worked for me, and lasted a long time, but I prefer the wooden method, it's so easy to bond to the hull.
Chas

Title: Re: Rudder Tube?
Post by: rnli12 on January 06, 2018, 06:48:24 AM
Also consider if the height of the rudder tube is above or below the waterline as it will need to have additional seals to prevent ingress of water.
Title: Re: Rudder Tube?
Post by: Nordlys on January 06, 2018, 08:51:29 AM
If you buy the Rudder and tube set you get a threaded outer tube with rubber seals top and bottom and hex nut to tighten down onto your drilled inner framework.
Too easy.
Modelboat bits sell all this ,
Title: Re: Rudder Tube?
Post by: tigertiger on January 06, 2018, 09:25:37 AM
My outer rudder tube is set in a piece of drilled wood. The length of the tube is only the same as the thickness of the wood, plus a little to allow it to protrude about 1mm from the hull and all is glued in place with epoxy. The top of the tube is above the water line.
Title: Re: Rudder Tube?
Post by: Tug-Kenny on January 06, 2018, 10:37:11 AM

The tops of my ruder tubes are never below the water.  That's just asking for trouble.   :}





Title: Re: Rudder Tube?
Post by: grendel on January 06, 2018, 11:25:54 AM
though my hull is wooden, I still have a hardwood block inside for the rudder tube
Title: Re: Rudder Tube?
Post by: nemesis on January 06, 2018, 02:36:04 PM
Have your outer tube as high as you can get it, it is surprising how much water finds it way up there. People do not realise what propwash does. nemesis
Title: Re: Rudder Tube?
Post by: Big Ada on January 06, 2018, 05:21:48 PM
Regarding what to use for the Tube, I use what comes to hand, brass, ali, plastic, even Old Biros.
Title: Re: Rudder Tube?
Post by: Mark T on January 06, 2018, 09:08:21 PM
When I was at the Coalville boat show I spoke the fella who made that huge warship.  I'm talking about the massive ship that he built a stand that lifts it in and out of the water.  Anyway both of his rudders are well below the water line and I asked him how he did it.  He said that he put a washer on the rudder shaft above the rudder and put an O ring above that.  He then did the same at the top of the rudder tube and basically then squeezed it all together.  He had never had a leak with such a simple solution to having very low rudder tubes.