Steering Pulleys (Sheaves)

[coopec43]

I've been working on the design of the yacht steering for some time now.

Originally I planned to use 8mm SS 7/19 cable but the experts said I should use 10 mm and pointed out the quadrant could take 10mm. The minimum diameter sheave for 10 mm cable is 7 inch (to avoid fraying) so I priced them and the Harken 178mm is $197 (plus freight). Since I needed about 10 of them that was out of the question.

My yacht is a 43ft Roberts Mauritius (center cockpit) so the steering cables are long.

I have now looked at using V belt pulleys and find I can convert the V of a A-Section pulley with minimal machining to take 10 mm cable. I will then use Bronze self lubricating bearing sleeves. . I suppose I could do the conversion myself by wrapping abrasive sand paper around a 10mm rod and spinning the pulley in a lathe or bench drill.

Can anyone see a fault with my plan?

[AndyEss]

What material are the V-belt pulleys made from? Most V-belt pulleys I’ve seen are stamped mild steel.
Epoxy paint them? Send them to a plating shop (Electroless nickel, hard chrome?) so corrosion (and galvanic corrosion) are minimized?
Inspect them frequently and make sure they are easily accessible for replacement.

[CassidyNZ]

Have you considered using closed circuit tubing for your cables?

I have a 44ft centre cockpit vessel too. My steering cables come out of the binnacle into the engine room. At that point they enter rigid outer cables which run to just about half way where there is a lubricating fitting, then back into the rigid outer cable to exit at the quadrant. Each end of the outer cable is anchored in a bracket to create the push/pull effect.

The result is there are only two sheaves, one on each side of the quadrant.

These cables are available from Edson, see the link below.

https://edsonmarine.com/8-foot-lengt...1-4-wire-rope/

They may appear costly but the result will be a low maintenance solution probably less expensive than the convoluted process of guiding open cables around your boat.

[coopec43]

The pulleys pictured are aluminum and that is what I planned to use. I would paint them but I recognize all steering pulleys need to be inspected regularly for wear. Thanks

[coopec43]

Originally Posted by CassidyNZ

Have you considered using closed circuit tubing for your cables?

I have a 44ft centre cockpit vessel too. My steering cables come out of the binnacle into the engine room. At that point they enter rigid outer cables which run to just about half way where there is a lubricating fitting, then back into the rigid outer cable to exit at the quadrant. Each end of the outer cable is anchored in a bracket to create the push/pull effect.

The result is there are only two sheaves, one on each side of the quadrant.

These cables are available from Edson, see the link below.

https://edsonmarine.com/8-foot-lengt...1-4-wire-rope/

They may appear costly but the result will be a low maintenance solution probably less expensive than the convoluted process of guiding open cables around your boat.

Yes, I had considered conduit and I was going to do exactly as you have done: conduit to the engine room. That would save a lot of sheaves and would make the job so much simpler.

But when I got advice from an expert in the game he advised against conduit as he said you can't monitor the condition of the cable. He drew the parallel with plastic coated lifelines which have been banned by the AYBC. (Of course there are plenty of yachts sailing around the world without problems with their conduit covered steering cable)

"the convoluted process of guiding open cables around your boat" You are not wrong!!

Thanks for that

[RaymondR]

That's a lot of pulleys and with just bushings you are going to have a lot of friction. Probably not overly important for hand steering but significant if you want to use an autopilot. Also those wire and pulley systems tend to be fairly high maintenance.

In the long term you may find it more practical to get short sections of large OD hollow alloy bar and machine the wire groove into the outer circumference and a sealed roller bearing housing into the ID. Far less friction, wear and maintenance.

[Wotname]

Originally Posted by coopec43

........
I have now looked at using V belt pulleys and find I can convert the V of a A-Section pulley with minimal machining to take 10 mm cable. I will then use Bronze self lubricating bearing sleeves. . I suppose I could do the conversion myself by wrapping abrasive sand paper around a 10mm rod and spinning the pulley in a lathe or bench drill.

Can anyone see a fault with my plan?

Hmm, I don't know if this a fault or my bad maths but it appears to me the width of the bottom section of the V profile in the one in your picture is about 5mm. That seems small for a 10mm cable and there doesn't seem enough "meat" in the cross section of the pulley to allow for much machining - it just looks like the wrong pulley to use in my eyes.

Also,if you are palling to spin the pulley in a lathe, why use sand paper on a stick instead of the cutting tool. I get the stick is a workable idea if using a bench drill.

EDIT: the SPB XPB might be a better size IMHO.

[coopec43]

The bottom section of the "V" is actually 7mm. The cable would not sit on the bottom of the "V"as it would be too wide at its widest point. Once the V was widened to accommodate the cable widest point it would then sit on the bottom of the V. Then some metal (1mm+) would have to be removed from the bottom of the V.

(I have an A-Section pulley at home and I have sat a 10mm round bar in the groove and very little metal has to be removed (Maybe a little over 1mm either side and the same at the bottom of the V.

My Son has a lathe and he has agreed to machine the pulley groove as well do the machining for the brass bushings. Thanks for your input.

[Wotname]

Originally Posted by coopec43

The bottom section of the "V" is actually 7mm. The cable would not sit on the bottom of the "V"as it would be too wide at its widest point. Once the V was widened to accommodate the cable widest point it would then sit on the bottom of the V. Then some metal (1mm+) would have to be removed from the bottom of the V.

(I have an A-Section pulley at home and I have sat a 10mm round bar in the groove and very little metal has to be removed (Maybe a little over 1mm either side and the same at the bottom of the V.

My Son has a lathe and he has agreed to machine the pulley groove as well do the machining for the brass bushings. Thanks for your input.

Clearly seeing it in real life is better than looking at it on CF
Good to hear your son is coming to the party!

[Ambler]

Instead of stainless steel wire you can use 12 strand dynex dux or similar. That will allow smaller diameter sheaves.

I have used 6mm for my 37ft centre cockpit and the guy I consulted about it, used 8mm for a 60ft yacht.

There is more stretch or creep as the Brummel spliced eyes take up, so perhaps add shackles initially.

I fitted a cleat to the quadrant to take up the slack and placed the stainless turnbuckles between the chain and dynex rope where I could reach them which in my case made it easier to adjust.

Perhaps this might work for you

[Tillsbury]

I would be all over using dyneema for this, especially since you're replacing all the sheaves. Way smaller blocks needed, way less friction, much less maintenance, and you can easily carry a spare or make one up on the spot. I cannot think of one reason to use wire in this application.

[CassidyNZ]

Originally Posted by coopec43

But when I got advice from an expert in the game he advised against conduit as he said you can't monitor the condition of the cable. He drew the parallel with plastic coated lifelines which have been banned by the AYBC. (Of course there are plenty of yachts sailing around the world without problems with their conduit covered steering cable)

Don’t mean to harp on but there is no comparison with cable steering and plastic coated lifelines. On my boat the cables run for 2.5 metres then the go through two greasing fittings where, on a regular basis, waterproof grease is pumped in via convenient nipples and the grease migrates up and down the cable.

My cables are now 22 years old. I pulled one out to check condition a couple of years ago and it was indiscernible from new cable. Your cables running around a dozen sheaves will experience exponentially more wear than greased conduit cables. Just sayin . . . . Don’t believe everything “experts” tell you.

Just as an aside, my previous boat (pulleys at two points) once slid down the back of a wave in the middle of the night, caused the helm to spin out of control, the chain jumped off the sprocket at the wheel. Then of course it jumped off the pulleys as well. Took me a few hours upping and downing in a lumpy sea to get everything back on the pulleys and sprocket, zero helm all the while. I wouldn’t even want to think about doing that with several sets of pulleys.

If you’re really going to go with the multiple pulleys, please be sure to have a retention device at each turn point to keep the cable on the pulleys if something comes loose. Putting all those pulleys right when you’re in the seaway and just you trying to fix, it will be a fresh little nightmare.

[coopec43]

Originally Posted by RaymondR

In the long term you may find it more practical to get short sections of large OD hollow alloy bar and machine the wire groove into the outer circumference and a sealed roller bearing housing into the ID. Far less friction, wear and maintenance.

A 10mm 7/19 stainless steel cable should not be used on anything less than a 7 inch pulley otherwise it will tend to fray. I therefore need about a 9 inch diameter pulley which are very expensive if you buy Lewmar, Harken, Ronstan or Edson. Roller bearings could be a consideration although brass bearings are very reliable.

[coopec43]

Originally Posted by Ambler

Instead of stainless steel wire you can use 12 strand dynex dux or similar. That will allow smaller diameter sheaves.

I have used 6mm for my 37ft centre cockpit and the guy I consulted about it, used 8mm for a 60ft yacht.

There is more stretch or creep as the Brummel spliced eyes take up, so perhaps add shackles initially.

I fitted a cleat to the quadrant to take up the slack and placed the stainless turnbuckles between the chain and dynex rope where I could reach them which in my case made it easier to adjust.

Perhaps this might work for you

I've been down that track!!

I was going to use SS cable but balked when I realised the cost of large diameter pulleys that would be necessary.

I then decided to use small pulleys and use Dynema rope. But how do you terminate it at the quadrant (and Pedestal) so that you can tension it up? If I spliced in some sort of hook that would double the size of the Dyneema and it would be too big for the quadrant. I thought I'd use Bluewave Dyneema terminal eyes (see picture below) but the price of them is hideous.

So then I decided to use SS at the ends and Dyneema in between so I could use the small 100mm pulleys.

But now I think the way to go is using V belt pulleys.

[coopec43]

Originally Posted by CassidyNZ

Don’t mean to harp on but there is no comparison with cable steering and plastic coated lifelines. On my boat the cables run for 2.5 metres then the go through two greasing fittings where, on a regular basis, waterproof grease is pumped in via convenient nipples and the grease migrates up and down the cable.

I don't disagree with anything you have said in your post. I suppose there are times when we have a few choices and the best one is not always clearly cut.

I most certainly will make sure the steering cable can't jump out of the pulleys. Thanks