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)..........

[stav]

Hi,

I am in the processes of trying to make the wheel steering better on my center cockpit westerly Conway. I have drilled out the sheaves and added bearings and this has improved things a lot.

The next thing I am going to work on is a larger diameter wheel rim which I have spent (this rainy afternoon) drawing on 3D CAD, Previously made an MDFB model but thought the 'nibs' were to big. I want ot do this to be able to sit on the cockpit coaming more comfortable and helm.

But the main reason for seeking advice is about the sprocket inside the pedestal as there is a little play between the sleeve with the sprocket on and the shaft. Not sure if it is a key way or a spline. Hopefully will attempt to take apart tomorrow. Photo attached.

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

 

[pvb]

CAD images look fine, but remember it will make movement around the wheel much more difficult.

Almost all of these systems use standard chain, so you should be able to get a bigger sprocket if you think that's a good idea.

Don't change the stainless wire; it's subject to very high loads. Dyneema would no doubt cope, but it wouldn't improve feel.

 

[stav]

ovement around the wheel much more difficult.

Yes agree but already difficult when wearing boots/oilies. May be I should just make up a tiller extension that will hook on to the wheel and a spindle??

 

[neil_s]

I reworked the wheel steering of an 8 ton centre cockpit Hilliard. I confess that I got a local engineering company to make the new wheel shaft and asked them to fit a sprocket with my selected number of teeth. I got a new bit of chain from the local motor-bike shop. If I remember correctly - you talk about chain pitch ( length between the pins) and width.
Tiller extension might just save a lot of work !

 

[Quandary]

I suspect you may have done this already but a ramble through all the drawings and variations in Jefa's (jefa.com) excellent website might provide some inspiration, not suggesting they have the answer to your question but the excellence of their engineering and presentatation is inspirational. I would rather be browsing in there than here anyday.

 

[coopec]

QUOTE " Could I increase sprocket size to in crease feel on the helm? "

With a 36 ft center-cockpit you have quite long steering cables so stretch is a problem. Are your cables 8mm? (Of course the quadrant would have to handle 8mm) The riggers making up the cables for my yacht said in a 38 ft center cockpit yacht they would not install cable steering with anything less than 8mm in cable diameter. My yacht is 43 ft so they recommended 10 mm as my quadrant could handle 10mm.

With SS cable the sheaves should be 7 in minimum diameter to avoid "fish-hooking". I made mine up out of "V" belt pulleys as Harken and Ronstan prices are hideous. (I've been trying to upload photos of my sheaves but I've given up)

As far as the wheel is concerned you wouldn't want to go larger surely?

Are you familiar with the Edson brochure?
https://edsonmarine.com/content/EB381SteeringGuide.pdf
View attachment 85165



I just downloaded Jpegcompressor. Let's see how good it is!

 

[anoccasionalyachtsman]

Having spent a fair bit of time racing an X-Yacht with a huge wheel I wholeheartedly agree with your wish, but I have to agree with people on the accessibility front - it is a pain climbing around it.

You're also quite right to be concerned that the feedback force will reduce with diameter, but have you also thought about the increased mass of the rim? I'd be a bit wary of making a feel-sapping flywheel.

 

[michael_w]

Why not one of These? A lot simpler.

 

[vyv_cox]

QUOTE " Could I increase sprocket size to in crease feel on the helm? "

With a 36 ft center-cockpit you have quite long steering cables so stretch is a problem. Are your cables 8mm? (Of course the quadrant would have to handle 8mm) The riggers making up the cables for my yacht said in a 38 ft center cockpit yacht they would not install cable steering with anything less than 8mm in cable diameter. My yacht is 43 ft so they recommended 10 mm as my quadrant could handle 10mm.

With SS cable the sheaves should be 7 in minimum diameter to avoid "fish-hooking". I made mine up out of "V" belt pulleys as Harken and Ronstan prices are hideous. (I've been trying to upload photos of my sheaves but I've given up)

As far as the wheel is concerned you wouldn't want to go larger surely?

Are you familiar with the Edson brochure?
https://edsonmarine.com/content/EB381SteeringGuide.pdf
View attachment 85165



I just downloaded Jpegcompressor. Let's see how good it is!

Using such large diameter cable you may like to consider your sheave diameters according to the attached file. I am seeing several recent accounts of cable fatigue and fracture on yacht steering systems.

My own view is that the guidelines in the file should be regarded as a minimum because steering systems concentrate the wire flexing over such a short length. Oscillating systems are always difficult to specify for fatigue avoidance.

 

[Rafiki]

Hi,

I am in the processes of trying to make the wheel steering better on my center cockpit westerly Conway. I have drilled out the sheaves and added bearings and this has improved things a lot.

The next thing I am going to work on is a larger diameter wheel rim which I have spent (this rainy afternoon) drawing on 3D CAD, Previously made an MDFB model but thought the 'nibs' were to big. I want ot do this to be able to sit on the cockpit coaming more comfortable and helm.

But the main reason for seeking advice is about the sprocket inside the pedestal as there is a little play between the sleeve with the sprocket on and the shaft. Not sure if it is a key way or a spline. Hopefully will attempt to take apart tomorrow. Photo attached.

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

Stav,
I'm not sure about this 'feel' that you are looking for. the fact that you have added some bearings suggests that the steering may have been stiff. I had that problem in my 36 foot Westerly Corsair and spent a lot on new bearings for inside the top of the pedestal and also changing the rudder bearings. In fact the solution was simply to slacken off the nuts holding the cables to the quadrant by a turn. It made all the difference !

 

[pvb]

With a 36 ft center-cockpit you have quite long steering cables so stretch is a problem. Are your cables 8mm? (Of course the quadrant would have to handle 8mm) The riggers making up the cables for my yacht said in a 38 ft center cockpit yacht they would not install cable steering with anything less than 8mm in cable diameter. My yacht is 43 ft so they recommended 10 mm as my quadrant could handle 10mm.

10mm cable is massively oversized. The Edson brochure you mentioned recommends 8mm cable for boats twice the size of yours! Jefa, one of the most respected manufacturers of steering systems, use 5mm or 6mm cable. My 37ft boat has Jefa steering with 5mm cable.

And, as Vyv Cox has mentioned, the ratio of sheave diameter to cable diameter is a crucial consideration if bending fatigue is to be minimised. Jefa work on a minimum ratio of 20.

 

[fisherman]

Almost sure this is a stupid question but why not use hydraulic?

 

[coopec]

10mm cable is massively oversized. The Edson brochure you mentioned recommends 8mm cable for boats twice the size of yours! Jefa, one of the most respected manufacturers of steering systems, use 5mm or 6mm cable. My 37ft boat has Jefa steering with 5mm cable.

And, as Vyv Cox has mentioned, the ratio of sheave diameter to cable diameter is a crucial consideration if bending fatigue is to be minimised. Jefa work on a minimum ratio of 20.

To equate cable diameter to the length of a yacht shows unbelievable naivety. I am not going to waste my time arguing with you.

The Edson brochure also says

The chart below is composed of information gathered from our many years of leadership in marine steering. Due to the many variations of yacht design in areas of hull shape, engine horsepower and sail configuration, final recommendations must be approved by your naval architect

 

[pvb]

To equate cable diameter to the length of a yacht shows unbelievable naivety. I am not going to waste my time arguing with you.

I'm sorry you feel that Edson are naive, most people consider them to be quite sensible manufacturers of steering gear.

 

[coopec]

Almost sure this is a stupid question but why not use hydraulic?

That is not a stupid question but when you read a person's comment saying something like " i've had hydraulic steering on my yacht for the last 20 years and it's getting to the point where it will have to be replaced. I can't wait for it to finally give up the ghost but I will not be replacing the hydraulic unit as I just can't stand the lack of feedback / feel."

 

[coopec]

I'm sorry you feel that Edson are naive, most people consider them to be quite sensible manufacturers of steering gear.
[/QUOTE

You can't even read their brochure

You have a problem but I'm no doctor so I don't know what it is called. I'm sure it would end in "ania" (and it would be hard to pronounce)

 

[pvb]

You can't even read their brochure

You have a problem but I'm no doctor so I don't know what it is called. I'm sure it would end in "ania" (and it would be hard to pronounce)

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.

 

[fisherman]

Yes, OK. The ones advertised with feedback incorporated no good?

 

[anoccasionalyachtsman]

Well, just so the forum can make a judgement on your intellect, here's the table from the Edson brochure.

I made mine some time ago.

 

[pvb]

I made mine some time ago.