Rudder tube arrangement

[Kevj]

I'm fitting out my inboard rudder and I'm looking for advice.

I've seen a few ways - glassing in a tube, bolting in the tube, nut on the outside and nut on the inside.... etc. etc.

What is the best way, to fit, a through the hull rudder? - specifically the through the hull set up tube/gland etc.

I've got a keel that run's to the back of the boat, I'm thinking of passing the rudder through the hull and down to the keel, which will have a bearing on top, which the stainless rudder bar will sit.

thanks

 

[oldsaltoz]

What material is the rudder stock and tube?

 

[Kevj]

Hi,

Well that's the question - it's a blank canvas at the moment.

The stock is going to be made out of sheet metal (painted and protected), the tube I'm not sure of the best material to use and fit.

The easiest way to describe the set up I'm thinking off is a stainless bar, going through the hull, down to the skeg, which will have a bearing sat on top for the rudder to rotate in. Inside the hull the tube will stretch above the waterline with a gland on top.

I've attached an image of the same principal.

I'm just trying to decide the best method/materials to fit the rudder tube into/on the hull.

thanks

 

[oldsaltoz]

Hi,

Well that's the question - it's a blank canvas at the moment.

The stock is going to be made out of sheet metal (painted and protected), the tube I'm not sure of the best material to use and fit.

The easiest way to describe the set up I'm thinking off is a stainless bar, going through the hull, down to the skeg, which will have a bearing sat on top for the rudder to rotate in. Inside the hull the tube will stretch above the waterline with a gland on top.

I've attached an image of the same principal.

I'm just trying to decide the best method/materials to fit the rudder tube into/on the hull.

thanks

The 'Normal' system is to have a stainless tube glassed with an epoxy resin between the deck and hull, as most of the stress in a t the lower end it's a good idea to grind a recess and place the tube into this; glassing is done by first filling the recess around the tube with micro-fibres and resin, smoothing it with a smallish round object like a fish paste jar and cleaning off any excess material around the gusset. let this cure then glass over using bi directional 300 gram sheets each one overlapping the last by 25 mm, you will need 4 to 6 layers. Do the same at the top, 4 layers should be plenty.

You will need bearings, one at the base in the skeg and another at the top, the top bearing should be designed to prevent loading the base of the bottom bearing.

Hope this helps,
any other questions.

 

[Kevj]

thanks for the reply.

OK here's a diagram of what I think it will look like. Does it look like I'm going on the right lines?

The deadwood will be laminated to the bottom of the hull, inside, it'll be about 50mm high.

The deadwood will have a hole approx 54mm in diameter. the rudder tube (stainless 316) will be 50.8mm diameter (2 inch) I'll place it in the deadwood hole and fill with epoxy and then glass.

Inside the rudder tube will be a Delrin bearing - how do I keep the bearing in place??

The Stainless rudder bar will be 25.4mm (1 inch) - the drawing isn't drawn to size btw!

thanks

 

[oldsaltoz]

First up you need to support the rudder stock from the top, this can be as simple as a 10 mm thick washer welded to the inside, the top end of the machined with a thread or a square and through bolt.

The bearing in your drawing is held by friction.

The lower bearing is a cup shape, this fits into a stainless steel cup or tube and is held in place with grub screws.

I would avoid adding any timber to the rudder tube, this only adds the risk of failure due to moisture and timber not mixing, an all epoxy structure will me a lot stronger and not prone to rot.

Hope this helps.

 

[Kevj]

Hello

I've done a lot of searching on T'internet and found this -

Someone had it made up for a Hurley22, replacing their rudder post. The beauty of it is that I can 'lock' it on the outside and inside with the threaded nuts and then epoxy them in.

If I have a 1" dia rudder shaft, what would you recommend for the OD of the rudder post?

Thanks for being helpful!

 

[benjenbav]

Hi Kevj, I've just had to replace my rudder asemblies owing to a failure of external wooden mounts. Some of it is dealt with on this thread:

http://www.ybw.com/forums/showthread.php?t=238298&highlight=nice+weather

I have some "finished" pictures as well but haven't uploaded them from my camera yet.

Good luck!

 

[Kevj]

Hi Benjenbav,

Pictures are always good!

I've just had a look at your thread and I notice you've used a through the hull skin fitting for the bottom of the rudder post.

thanks
Kev

 

[benjenbav]

This is the finished (well, apart from final painting) article:

 

[Kevj]

Another question!

What size of rudder tube shall I use if my rudder shaft dia is 1"?

thanks

 

[oldsaltoz]

You need enough space between the rudder stock and tube to form a bearing, so at least half an inch larger than the shaft/stock.