Easy Sarah Rudder Shaft Length ???

Wheel, tiller and autopilots
Chrisg
Posts: 141
Joined: Wed Feb 17, 2010 6:55 am
Location: Country Victoria

Easy Sarah Rudder Shaft Length ???

Post by Chrisg » Mon Sep 05, 2011 8:28 pm

For those who have asked I offer the following as purely a guide. ;)
When I did some rough measurements I came up with the length of ruddershaft on Outback Dreamer as 1414mm total length. This measurement is the section glued in the rudder stock up to approximately 50mm above the top of the 93 x 19 upper chine. In the beginning I starterd with shafts 1650mm long and cut them once they had been inserted and measured in the upside down hulls.

Would i do it differently if done again? No :!:

I measured then as this:
Length in the rudder stock - 400mm
Synthetic washer - 10mm
Build up under the hull in which rudder shaft goes thru - 35mm
hull ply - 9mm
keelson - 40mm
from keelson to top 920mm approx +/- 20mm (its dark and could not see well) :roll:

****Note 1.**** these measurements are taken on our boat Outback Dreamer. Other boats may have different steering arrangements varying the rudder shaft length.

*****Note 2.**** the measurement reference to the upperchine is taken with the boat up the finished way, not up side down.

****Note 3.**** Outback Dreamer uses twin hydralic steering with a fluid link.

****Note 4.**** We take no responsability for the length others cut their rudder shafts at! :|
Chris & Michelle

Outback Dreamer - Sarah 23
http://www.outbackdreamer.com

sea_bee
Posts: 107
Joined: Sat Jul 09, 2011 6:09 pm
Location: Pillar Valley NSW

Re: Easy Sarah Rudder Shaft Length ???

Post by sea_bee » Thu Sep 08, 2011 1:11 pm

Hi Chris

Is there any provision for an anode on the rudder shafts?

I have only seen a rudder completed and have not seen the details in the plans. It seems as though there is no gap between the top of the rudder and the bottom of the hull to fit an anode in there.

Chris

terryk
Posts: 320
Joined: Wed Jan 10, 2007 10:37 pm
Location: Gosford

Re: Easy Sarah Rudder Shaft Length ???

Post by terryk » Mon Sep 19, 2011 8:14 pm

Hi Chris,
Do you need an anode on the rudder shaft :?: Mine is a cable and chain system, all the materials are stainless steel so there should not be a problem with dissimliar metals causing corrosion and there is no electrical currents attached.
cheers
terryk

puremajek
Posts: 751
Joined: Thu May 04, 2006 7:36 pm
Location: Brisbane Australia

Re: Easy Sarah Rudder Shaft Length ???

Post by puremajek » Tue Sep 20, 2011 9:41 am

'Removed'
Last edited by puremajek on Thu Sep 22, 2011 7:23 am, edited 1 time in total.
James
______________________________________________
http://www.diycatamaran.com
http://www.puremajek.com
______________________________________________

puremajek
Posts: 751
Joined: Thu May 04, 2006 7:36 pm
Location: Brisbane Australia

Re: Easy Sarah Rudder Shaft Length ???

Post by puremajek » Tue Sep 20, 2011 9:42 am

Is there any provision for an anode on the rudder shafts?

I have only seen a rudder completed and have not seen the details in the plans. It seems as though there is no gap between the top of the rudder and the bottom of the hull to fit an anode in there.
Hi Chris
I would have a chat to Peter, I am unware of any EASY's having this. Not to say you can't, just thinking it may be unnecessary or could be positioned elsewhere.
James
______________________________________________
http://www.diycatamaran.com
http://www.puremajek.com
______________________________________________

sea_bee
Posts: 107
Joined: Sat Jul 09, 2011 6:09 pm
Location: Pillar Valley NSW

Re: Easy Sarah Rudder Shaft Length ???

Post by sea_bee » Tue Sep 20, 2011 10:48 am

Terry's comments have me wondering about this now.

I know that stainless steel is at the opposite end of the table of metals to the weak metals like zinc and aluminium. It is therefore less prone to electrolysis or galvanic corrosion, but I thought that it was still a potential problem.

I know that anodes on ss prop shafts are common. This may be because of bronze stuffing boxes and bearings. But I have seen anodes on rudder stocks on yachts.

I'll have to do some more research on this. It did worry me when I saw the original post and no obvious allowance for an anode.

kjay
Posts: 149
Joined: Thu Oct 26, 2006 2:03 am
Location: brisbane

Re: Easy Sarah Rudder Shaft Length ???

Post by kjay » Tue Sep 20, 2011 4:36 pm

Hi, If you are at all worried about corrosion then have a look at the posts about composite rudder shafts, Excel composites here in brisbane make a series of tubes with close inner and outer diameters for tubes, I believe 44c and Madaz went down this path, I have gone composite tube and stainless shaft ( I am a better welder then gluer).
John

44c
Posts: 1147
Joined: Tue Aug 08, 2006 5:08 am
Location: Hervey Bay, Qld

Re: Easy Sarah Rudder Shaft Length ???

Post by 44c » Fri Sep 30, 2011 7:28 am

My concern with that setup is that the shafts may be stronger than the tubes. Hit something solid and you may tear out the rudder tubes, which could then let the water in!

Unless you have kickup rudders of course. I wouldn't have a boat without them now!

sea_bee
Posts: 107
Joined: Sat Jul 09, 2011 6:09 pm
Location: Pillar Valley NSW

Re: Easy Sarah Rudder Shaft Length ???

Post by sea_bee » Fri Sep 30, 2011 10:53 am

44c wrote:... the shafts may be stronger than the tubes. Hit something solid and you may tear out the rudder tubes...
The rudder tubes are really only the guide to the shaft. The required strength is in the top and bottom support fillets on the tube bearings, and not the tube itself. I think the first thing to fail would be the bearing support.

Jim
Posts: 691
Joined: Fri May 19, 2006 8:25 am
Location: Cairns

Re: Easy Sarah Rudder Shaft Length ???

Post by Jim » Sat Oct 01, 2011 9:10 pm

While the above comments may be of concern to some, you can only prepare for so many "so what ifs". The bottom bearing area on the Easys is seriously strong as it passes through and is glassed to the keelson (not sure about the spelling). The top bearing support is not so strong and doesn't need to be as it is some distance from the bottom where all the action takes place. In normal forward motion to bend or rip off the rudder you would have to first get past the mini keels. If you manage to do all that, then I would suggest you don a life jacket and grab your EPERB because you will be in deep s#*t and your boat will not be well.
Don't over think things, just follow the designers plans, enjoy the build and hit the water, not the rocks.
Jim.

Post Reply