Autopilot Direct Drive on H34

[WasabiRush]

I have an '86 H34 with the sometimes infamous ST4000+ computer and helm wheel drive. It worked fine for the past year, but now I'm getting the dreadful Low Battery error. I wired it directly to a fully charged battery and still get the error. My options are to buy a replacement computer that will work with the wheel drive or install a direct drive . Has anyone installed a direct drive (of any manufacturer) in an H34? Based on the boat layout and rudder configuration, I don't see how to install a direct drive.

TIA.

 

[kloudie1]

I have thought about the same thing at times, Rush. I think a drive arm could be fitted below the drive wheel .. the top of the shaft tube might have to be lowered and/or the rubber hose shortened? A mount for the linear drive would have to be fabricated on the ceiling of the aft cabin. .. alternately, the drive arm could be installed on the rudder shaft in the lazarette and a linear drive mount fabricated in there..
Edson Marine: Autopilot Tiller Arms (926 - 836)
The arm might be able to be mounted above the drive wheel extending aft and the linear drive mounted above the aft water tank. The attached from Claude Auger with the aft bulkhead removed shows the space above the tank..

 

[WasabiRush]

Thanks. That's a possibility. I've only had that cover off once and don't remember if I have that angle iron. If so, it's possible to hang some brackets on it to mount the direct drive.

 

[Artey1]

Thanks. That's a possibility. I've only had that cover off once and don't remember if I have that angle iron. If so, it's possible to hang some brackets on it to mount the direct drive.

Probably don't want to do that, that angle iron is your rudder stop for the cable steering. There should be room above the existing quadrant to attach another slim profile arm clamped or bolted to the rudder post extending aft above the water tank and then connecting that to the direct drive which would ideally sit to port of the water tank fill/vent hoses.

 

[jviss]

Bear in mind that there will be tremendous forces on the linear drive mount, so it can't be just some flimsy piece of angle iron or some such. It should be solidly mounted to the hull or a structural bulkhead so that the force from the rudder is transmitted to the hull, in such a way that it's distributed and doesn't cause any measurable deflection of the mounting surface.

 

[WasabiRush]

That angle iron doesn't look flimsy, but I get your point.

 

[jssailem]

slim profile arm clamped or bolted to the rudder post

For the linear drive to deal with the forces involved you will need to both clamp and through bolt the tiller arm onto the rudder shaft.

Not sure there is enough space to allow the tiller arm to move within the required space from the pictures of the angle bracket. You will want the drive unit to be securely positioned on the boat. You want no movement of the drive unit. Hanging from the angle iron would be problmatic.

I know that the wheel pilot is frustrating at times as it ages. The Hunter 34 is well within the designed parameters of the AP at 8,000 lbs and a fin keel. It coudl be that the AP needs an overhaul. They were not built for forever use.

 

[Tally Ho]

I am fighting issues with my old MK1 wheel pilot And am considering options…

1) new linear drive. First thing to check was whether or not I had any room on the rudder shaft for a tiller arm.


The good news is I do think I have room for the tiller arm. It can bgo above the quadrant. The bad news is that a new linear drive system is $3,600. Can an old ST4000+ drive a linear drive? I see a few used drives for sale.

2) new Evo 100 system…about $1,600 I think…haven’t shopped around too much yet.

3) a brand new, old stock MK2 autopilot, with rudder sensor. Found one for about $825.

4) purchase just the wheel drive(MK2) (no compass, no head unit). Lots available for $650 or so. I assume my St4000+ system will drive it.

5) replace belt and other wheels, etc on my old MK1 system. The compass, control head, drive motor are OK. But the belt seams to skip in strong winds (especially if the boat is over canvasses or not balanced).

Decisions, decisions…


Greg

 

[WasabiRush]

I thought I'd provide an update. I installed a Nac-3 AP and first impression is that it works okay with the MK2 wheel drive. I purchased the Virtual Rudder Feedback (VRF) package that included the AP and compass. I learned during the configuration that VRF cannot be used with sailboats. The AP should still work okay (I haven't completed the sea trial commissioning), but it won't be integrated with the B&G SailSteer features. I just ordered the RF25N (rudder feedback sensor) and hope to install it next weekend. I'm not sure yet how I'll be able to mount it and connect it to the steering quadrant.

Had the VRF package description stated it doesn't work with sailboats, I would've saved $50 by including the sensor in the beginning.

 

[kloudie1]

Here is a picture of my rudder position sensor .. Since it is inverted, the wires had to be reversed ..

 

[WasabiRush]

Here is a picture of my rudder position sensor .. Since it is inverted, the wires had to be reversed ..
View attachment 208793

What brand is it? The RF25N has a N2k connector, so hopefully it adjusts for being inverted. Did you drill and tap the quadrant for that connection?

 

[kloudie1]

That is a Raymarine unit.. I drilled two small holes to mount the little spherical ball post that the link snaps onto. The bolts are right behind the rudder stop. Inverted mounting is not uncommon for the sensors; I would think that Simrad would have advice in the literature on connecting their unit.

 

[Tally Ho]

I ended up buying the new, old stock ST6000 AP with the rudder sensor…

Real happy with it so far.

here is a bit of the install details…

Around 6:10, you can see the rudder sensor mount.


Greg

 

[WasabiRush]

I got the RF25N rudder feedback sensor installed over the weekend. I fabricated the bracket to ease the rod leveling aspect of the install. It appears to work okay in manual mode, but when I engage the AP, the helm spins a bit and I get a no rudder response error. My research shows that's not uncommon when sitting still in the slip. I'm hoping to get out this weekend to do the sea trial of it and the AP.

Here's a few pics.