EV-100 Autopilot 4000Mk2 Wheel Drive Repair

[jssailem]

you'd also have to address the gear material on the motor.

On first look, at this point the motor steel shaft comes out of a "gear box" that as Greg indicates "wise to not open. I have not looked in side - yet. The steel shaft from the gear box drives a large toothed gear inside the wheel drive. The gear looks to be made of plastic. It drives the toothed belt. The belt teeth have a "rubberized" surface that wraps around the smooth surface of the Drive Wheel. The caution I stated in the description about "Do not get lube between the belt and the drive wheel" is critical to the operation of this design. I guess if you were redesigning this yo could put teeth about the drive wheel. While positive in making the drive wheel function, it would negate the ability to override the AP in an emergency. Because there is slippage you can force the helm to move even if the belt on the drive wheel is tensioned. Not sure if this was a design feature or a happy discovery.

When I had a jam on the clutch lever I was still able to control the boat to get into me slip (though it required some force to move the wheel). Not sure what would happen with a linear drive is there was a jam. Is the rudder just stuck?

Good design considers all of these events and tries to resolve them.

 

[dLj]

I've just gone through all the drawings and the video of the guy doing the motor rebuild. I now understand better all the bits and parts of this drive. You don't have to worry about the gear material on the motor. I hadn't understood the whole mechanism of this drive unit. I'd still not sure I'd want aluminum for that large toothed gear, I think you'd do better in Delrin. However, it might be a better option than I first thought. Apologies to @jeepbluetj .

You would certainly want to use a good grade of aluminum, I'd use a 5000 series alloy if you did go with aluminum.

dj

 

[Stu Jackson]

Not sure what would happen with a linear drive if there was a jam. Is the rudder just stuck?

Great question, John. I used to know the answer, but one too many of happened.

There are so many skippers who have installed below decks APs (electric & hydraulic) that the answer should appear here soon.

 

[SoSound]

There are so many skippers who have installed below decks APs (electric & hydraulic) that the answer should appear here soon.

Oh, boy... here we go... ...

If it's an AP computer "jam" then I'd just turn the power off at the chart plotter, if that didn't work then I think I'd trip the navigation circuit breaker. If that didn't work and it's a mechanical jam, at this point I have no idea. Something for me to inspect and get to know better.

 

[jssailem]

Dave... I seek out the opportunity to ask a question that we might not have considered.

My wheel pilot did jamb. The Clutch Lever failed and the Wheel drive belt was in AP mode. I flipped the AP to standby. This is supposed to disengage the electrical system. It did. But with the Clutch Lever failure the drive belt was still tight. You can force the helm to respond. This means the Drive Wheel has to slide (rotate) against the belt. The Drive Wheel is smooth surface. The belt has a bit of a rubber textured toothed surface. It slides but it also provides a bit of friction.

You can release the clutch tension wheel on one side of the motor, but the clutch lever is still in tension. You would need to remover the cover which is attached to the helm spokes to free the helm. This is what I did.

Considering the linear drive motor that works under the deck, I am not sure how you would free the rudder shaft. I suppose there is a release you could trigger. At least I would hope there is. I would not like to take a hammer to the linear motor or shaft, but I guess a big enough hammer would serve to disable the AP till one could get to port.

 

[dLj]

Dave... I seek out the opportunity to ask a question that we might not have considered.

My wheel pilot did jamb. The Clutch Lever failed and the Wheel drive belt was in AP mode. I flipped the AP to standby. This is supposed to disengage the electrical system. It did. But with the Clutch Lever failure the drive belt was still tight. You can force the helm to respond. This means the Drive Wheel has to slide (rotate) against the belt. The Drive Wheel is smooth surface. The belt has a bit of a rubber textured toothed surface. It slides but it also provides a bit of friction.

You can release the clutch tension wheel on one side of the motor, but the clutch lever is still in tension. You would need to remover the cover which is attached to the helm spokes to free the helm. This is what I did.

Considering the linear drive motor that works under the deck, I am not sure how you would free the rudder shaft. I suppose there is a release you could trigger. At least I would hope there is. I would not like to take a hammer to the linear motor or shaft, but I guess a big enough hammer would serve to disable the AP till one could get to port.

John,

Great question. One I need to answer for myself as I have a linear drive. I can tell you with it engaged, I'm not getting slippage as you get with your wheel pilot. Indeed, I'm not moving the wheel, it is quite solidly controlled by that linear drive. I have just put the autopilot into standby, to date, to release it. You have given me an assignment I need to figure out. I'll have to dig into that system and see what could go wrong to not allow it to release and how to overcome that.

dj

 

[Davidasailor26]

It is a good question. Looking back through pictures of my linear drive it looks like there might be a pin that you could pull to disconnect the ram -

If that doesn’t work the ram connects to its own tiller arm, not directly onto the quadrant. It looks like it would be possible to loosen the attachment from that tiller arm to the rudder post enough to let it slip while hand steering -

I’ll need to look at it more closely and figure out a good procedure. Total lockup of the ram is probably uncommon but something that you would need a way out of.

Having said that, the upside of the linear drive is that if the steering chain, cable, or quadrant fails you can still use the linear drive to turn the rudder post.

 

[Head Sail]

But with the Clutch Lever failure the drive belt was still tight. You can force the helm to respond.

I think this may be the cause of your cracked ring. I would not force the helm to respond unless a dire emergency.

 

[jssailem]

I would not force the helm to respond unless a dire emergency.

I agree. I was coming into the marina after cruising for about 3 hours under AP control.

I put the AP in standby, flipped the Clutch Lever and


Tried to release the clutch lever ecentric. No success.
When things go bad remember you need to control the boat.

It could have happened then, but I did not see any evidence of that occurring.

 

[SoSound]

Considering the linear drive motor that works under the deck, I am not sure how you would free the rudder shaft. I suppose there is a release you could trigger. At least I would hope there is. I would not like to take a hammer to the linear motor or shaft, but I guess a big enough hammer would serve to disable the AP till one could get to port.

That is the part that I need to study some time soon. My unit is probably the exact same thing as what @Davidasailor26 has.

 

[jaysweet]

I think this may be the cause of your cracked ring. I would not force the helm to respond unless a dire emergency.

Nah: I think there's ample evidence (many posts, mine among them) that say the rings just either aren't strong enough, or they deteriorate over time. I'm not terribly upset by mine dying after 17 years, but it does seem overly cheap that Raymarine hasn't made this part more robust.

 

[Davidasailor26]

That is the part that I need to study some time soon. My unit is probably the exact same thing as what @Davidasailor26 has.

I poked around at mine more today. This is the view from an access panel in the aft cabin -

The ram is secured to the tiller arm with an easily removed hairpin cotter pin. Unfortunately once that pin is removed there’s not quite enough room to slip the ram off before it hits the quadrant. So I think if the ram ever needed to be disconnected you’d need to loosen that tiller arm from the rudder post, slide it down about 1/4”, then slip the ram off.

 

[SoSound]

@Davidasailor26, I haven't had a chance to look, yet... is it hydraulic or electrical? I seem to remember hoses in the lazzarette, if it's hydraulic, then I would think that powering off the AP would kill the hydraulic pressure. Does the manual say anything about emergency disengagement?

 

[Davidasailor26]

@Davidasailor26, I haven't had a chance to look, yet... is it hydraulic or electrical? I seem to remember hoses in the lazzarette, if it's hydraulic, then I would think that powering off the AP would kill the hydraulic pressure. Does the manual say anything about emergency disengagement?

The ram is hydraulic, driven by a pump in the aft lazarette. I agree that most failures could be worked around by just powering down the system, except maybe some strange jamming in the ram itself. So needing to disconnect the ram in a hurry isn’t too likely anyway.

 

[SoSound]

@Davidasailor26, sounds like one of those “visual inspection” things to be added to the list. To make sure that the pin is in place and everything moves freely.