Rudder Tube Material

[Zen Zero]

The last job before launching was to be replacing the rudder bushings, having obtained the yard's permission to dig a rudder pit, however on removing the lower bushing i noticed the aluminium tube was all corroded away, only the glassing-in was stopping the boat from sinking (that and the fact that she was on dry land). An hour with a grinder later saw me with 3 pieces of tube in hand and the task of procuring a replacement.

I kinda like the idea of replacing it with a GRP tube. In fact I can't think what an aluminium tube was doing there in the first place considering the rudder shaft is stainless steel.

Would anyone like to comment on:

Where to get a grp tube
Why the original was aluminium
Failing that should I replace with stainless steel (does stainless bond well with epoxy)?

While we're on the subject, what material would you use for the bushings?

Thanks

 

[30boat]

A quick Google will show loads of results.Like this
http://www.captrad.co.uk/Products/Product_Display.asp?Products_Cat_ID=6&Products_ID=78

 

[Adamastor]

I'd used Vesconite bushings- it's a Saffer product, but you should be able to track it down in Blighty. It's better than acetal, IMHO, because it is very dimensionally stable in water, so it won't swell or stick. A mandrel-wound GRP tube should be easy to source, too. There are some aluminiums that are fairly inert to electrolysis, and yours may have originally been anodised. I know that JP3 use ali for some of their tubes, but they also do some very exotic alloys, so it's probable that your tube may not just be ordinary ali either.

 

[oldsaltoz]

Our cat has fibreglass rudder tubes but for long.

I plan to replace them with stainless tubes that will have a flange on the bottom to make classing in a doddle.

I discovered this the first time we lifted her out, signs of glassing at the lower hull end, I cut the steps out of the back ready to replace the glass tube and what looked like several repairs to the lower joint.

Problem was, we only had 2 days and it was going to more than that to the tubing shipped.

So I gave it an extra bit of glass and built a watertight compartment above it, so if leaked it would be contained.

This rudder was the one damaged in the recent Cyclone Yasi, and the compartment is working well.

Note: If you plan to install a stainless tube, look for a backing to clamp the tube to or build in an extra bulk head to support
it.

Good luck.

 

[Stemar]

I had almost exactly the same situation with Jissel a few years ago. The original copper pipe had corroded away and I must have broken it free removing the rudder, but only found out a week before the (non negotiable) lift-in.

A nose round the yard found an old GRP windsurfer mast, which was tapered nicely. I cut myself a section to fit over the original glassing in of the copper and epoxied in place. It's worked perfectly and should be good for the life of the boat. Cost: Nil, give or take a near heart attack when I realised I had a problem!

 

[Tranona]

On my plywood boat the rudder tube is a galvnized steel pipe with a flnge either end. Has a grease nipple so that it can be filled with grease. Bearings top and bottom are bushes made from Delrin. Astainless tube would be just as good as would a grp one provided you can figure out a way of holding them in securely. Have the tube (GRP is readily available from specialist suppliers of stern gear) oversize so that you can put a replaceable bush in.

 

[SvenH]

Epoxy bonds stainless steel quite well but may work itself loose due to different expansion coefficients.

If you go with ss, also leave room for a sikaflex seal on the outside of the hull.

 

[Bosun Higgs]

Where to get a grp tube

east coast fibreglass though I would look round to see if I could find an epoxy tube. Try people like Norris who supply sterngear.

Bond in the tube with epoxy not polyester.

 

[Zen Zero]

I've decided to try to make my own tube by wrapping a PVC drainpipe in glassfibre cloth and epoxy. I'll let you all know how it goes.