Can I show you my rainy afternoon CAD wheel rim? And ask a question about chains and sprockets. (Or has anybody got any wheelie good ideas)..........

[lw395]

I think a big wheel that you can sit alongside, where you can see the jib is the only wheel I'd really want.
Small wheels that you have to sit or stand behind, I just don't like, except maybe indoors on a motorsailor.
On our boat, I can move across the cockpit, steer the wheel from the leeward side and trim the jib.
I can comfortably steer from either side seat in the cockpit for a long time. Or if it's lively with the kite up I can stand behind the wheel and drive the boat harder.
I don't like yachts with little wheels that look like they'd fit a mini cooper.
I'd rather have a tiller if you can't have a big wheel.
But each to his own.
As for cable size, the wheel has a certain mechanical advantage, there's a certain amount of force a helmsman can be expected to produce.
I think outsize wire will be an own goal, as it takes a lot of work to flex it and its initial stretch from zero to a reasonable preload will be high as the strands settle. I'm not convinced the fatigue life will be any better either as you're flexing the wire around a similar or worse cable dia/pulley dia ratio.
The big thing perhaps is to have a well designed rudder so the steering loads are reasonable in the first place.

Also, is galv steel cable still preferred over stainless for steering lines?

 

[rogerthebodger]

I have just made a new stainless steel wheel for a friends boat.

It consists of 2 rolled tubular rings from 25mm tube one being about 800 mm O/d the other about 350 O/D.

The boss is 2 pieces 20.. thick O/D 70mm bored to suit the steering shaft.

6 x 8mm redial holes fir the 10mm dia spoked ate drilled in the boss, the inner ring and the outer ring. These holes only through the inside wall of the outer tube.

The boss is clamped together with 6 axial screws drilled in the one boss and tapped into the other.

Sprockets can be obtained from your local bearing supplier and were in my time from fenner as is drive chain (stainless steel transmission drive chain can be obtained if need be.

I use hydraulic steering and with the check valves removed you can get all the steering feel you need. This does limit you to a single wheel steering and direct drive auto pilot.

 

[stav]

Hi,
Thanks for the replies.
Quandry, thanks for the link to Jefa, no have never looked at this before and really interesting.
Likewise Coopec the Edisson stuff really interesting.
Michael_W, yes that was the sort of thing I was thinking of making as an alternative to enlarging the wheel.
LW395, I agree part of the joy of sail is the feel through the wheel and have seriously considered down sizing back to a yacht with a tiller but then that might stop my family coming on board the two or three times a year they do.
I have no intention of changing things like the sheaves etc as I cannot afford it, if I could afford a complete new wheel system I would but if I had that money to spend I might fit a roller reefing genoa first!
Rafiki, good point about the rudder bearings. I have felt these from the rudder end and with cables removed and they seem quite free. This project is abut making helming more comfortable having reduced friction in the system.

Comments about wires have some merit but I changed the wires not long after buying her eight years ago. (After a bad experience on the Hillard I owned). They are 6mm 7x19. The existing sheaves are about 100mm diameter. None of which I intend to change. Although I am curious about the dynema after 6mm dynema seems to have nearly twice the breaking strain of the 7x19 6mm wire..... Just the issue of chafe, especially as I know one sheave is slightly miss-alighted. I wonder if galvanised would be better?

Overall I might just make up a tiller extension for the wheel but since I can make up the wheel from 'collected' bits of mahogany and can make it so that I can detach it if I need to got to be worth a try?

Will share the results once I have tried something!

 

[pvb]

Comments about wires have some merit but I changed the wires not long after buying her eight years ago. (After a bad experience on the Hillard I owned). They are 6mm 7x19. The existing sheaves are about 100mm diameter. None of which I intend to change. Although I am curious about the dynema after 6mm dynema seems to have nearly twice the breaking strain of the 7x19 6mm wire..... Just the issue of chafe, especially as I know one sheave is slightly miss-alighted. I wonder if galvanised would be better?

Your wire is too big for your sheaves, and you will get fatigue failure in due course. Jefa advise "The 100 mm diameter sheave sets should be used with 5 mm steering wire. The 140 mm diameter sheaves should be used with 6 mm steering cable. It's not advisable to use 6 mm cable on the 100 sheaves as the cable will fatigue quickly due to the too small bending radius."

Your easiest solution would be to replace the 6mm wire with 5mm wire.

 

[lw395]

Hi,
Thanks for the replies.
Quandry, thanks for the link to Jefa, no have never looked at this before and really interesting.
Likewise Coopec the Edisson stuff really interesting.
Michael_W, yes that was the sort of thing I was thinking of making as an alternative to enlarging the wheel.
LW395, I agree part of the joy of sail is the feel through the wheel and have seriously considered down sizing back to a yacht with a tiller but then that might stop my family coming on board the two or three times a year they do.
I have no intention of changing things like the sheaves etc as I cannot afford it, if I could afford a complete new wheel system I would but if I had that money to spend I might fit a roller reefing genoa first!
Rafiki, good point about the rudder bearings. I have felt these from the rudder end and with cables removed and they seem quite free. This project is abut making helming more comfortable having reduced friction in the system.

Comments about wires have some merit but I changed the wires not long after buying her eight years ago. (After a bad experience on the Hillard I owned). They are 6mm 7x19. The existing sheaves are about 100mm diameter. None of which I intend to change. Although I am curious about the dynema after 6mm dynema seems to have nearly twice the breaking strain of the 7x19 6mm wire..... Just the issue of chafe, especially as I know one sheave is slightly miss-alighted. I wonder if galvanised would be better?

Overall I might just make up a tiller extension for the wheel but since I can make up the wheel from 'collected' bits of mahogany and can make it so that I can detach it if I need to got to be worth a try?

Will share the results once I have tried something!

If you've been sailing the boat for a while, can you guesstimate the force on the wheel and hence the safety margin in the wire if you go down to 5mm?
Can you work it the other way, what's the design force on the rudder and what's the leverage of the steering quadrant?

Some Dyneema might be a poor choice due to creep. Consider Vectran or DYOR about the Kevlar they use for lifts. I am a bit out of date with modern rope I think, so many flavours of everything now.

 

[stav]

Thanks, actually been and checked the cables and they are actually 5mm. Have also taken out the shaft and replaced the keyways and added a m8 grub screw, no play in the sprocket now. Reassemble tomorrow.

Wheel rim might have to wait a week or so, might try and get a sail in tomorrow........

 

[pvb]

Thanks, actually been and checked the cables and they are actually 5mm. Have also taken out the shaft and replaced the keyways and added a m8 grub screw, no play in the sprocket now. Reassemble tomorrow.

Excellent, sounds like your wire and sheave sizes are nicely matched. Good luck with re-assembly (and the diet ).

 

[stav]

Cheers, pvb. (First thing to hand to protect the worktop, made a huge difference and can recommend).

 

[stav]

Prior to lockdown had mostly made my wheel rim. A bit rough and ready but along with remaking the sheaves and modern teflon lubricant so pleased with the results. I have to take care with sail balance now!

So thought I would show a follow up picture to the post.

 

[pcatterall]

Well, just so the forum can make a judgement on your intellect, here's the table from the Edson brochure. The last line shows a recommendation of 7.94mm wire rope for a steering system on a boat with a LWL of 60-75ft.

View attachment 85176

Not wanting to interfere in an intense debate but the chart uses waterline length. Clearly the distance from the wheel is the important dimension. Is the chart for CC yachts ?

 

[Bilgediver]

But does anybody know make? If you can get spares? Could I increase sprocket size to increase feel on the helm? Perhaps 20% more teeth to match increase in wheel diameter? Where might I get spare sprockets? What technical info describes a chain and sprocket do they have a module?

Could the stainless steel wire be changed for modern rope? Would this improve feel?

Thanks for thoughts in advance.

Cheers

The sprockets are probably standard Fenner products and available as pilot hole drilled from many suppliers such as this.

Industrial Sprockets - Fenner Sprockets


So long as you use the correct 7 X 19 flexible stainless wire you will have no problem and certainly a better option than rope. I have 4 mm on my Westerly Chieftain which gives no problems, it is possible on a larger boat you have 5 mm.

 

[rogerthebodger]

The sprockets are probably standard Fenner products and available as pilot hole drilled from many suppliers such as this.

Industrial Sprockets - Fenner Sprockets

Then I use any fenner sprockets or pullies I go for taper lock bushes so no need to have the problem of having the pulley machined.

I also used taper lock bushed when I fit ball bearings into free running pullies.

 

[pvb]

Prior to lockdown had mostly made my wheel rim. A bit rough and ready but along with remaking the sheaves and modern teflon lubricant so pleased with the results. I have to take care with sail balance now!

So thought I would show a follow up picture to the post.

That looks good! How did you fabricate it?

 

[pvb]

Not wanting to interfere in an intense debate but the chart uses waterline length. Clearly the distance from the wheel is the important dimension. Is the chart for CC yachts ?

I don't think distance from the wheel is significant. The loads in steering cable aren't high enough to cause meaningful stretch, despite what Coopec claims (I wonder what happened to him?)

 

[stav]

That looks good! How did you fabricate it?

I cut out 5 segments 20mm x 20mm with a notch in one set in the middle for the spindles and a notch at the ends for the other five. All epoxied together. Routered to a tapered cross ecetion.