Autohelm ram replacement

[KAM]

After many years heavy use my Autohelm ram has finally worn out. One of the planet gears has chipped. I've bought a cheap generic 12v ram off eBay to play about with. Has anyone else tried these. There seems to be plenty of thrust but a bit slower than the old one. The current draw is slightly higher than the Autohelm. I was thinking of trying a solid state relay to drive it and save damaging the control head. I'm not sure if the output is straight on/off or is it more sophisticated. Anyone else tried this.

 

[PaulRainbow]

After many years heavy use my Autohelm ram has finally worn out. One of the planet gears has chipped. I've bought a cheap generic 12v ram off eBay to play about with. Has anyone else tried these. There seems to be plenty of thrust but a bit slower than the old one. The current draw is slightly higher than the Autohelm. I was thinking of trying a solid state relay to drive it and save damaging the control head. I'm not sure if the output is straight on/off or is it more sophisticated. Anyone else tried this.

Assuming an electric linear drive....

Power to the drive is on/off, reversed polarity to change direction.

 

[KAM]

Should work with the solid state relay then. The generic unit has limit switches. It will be interesting to see how it compares with the rubber disc stop on the Autohelm unit.

 

[KAM]

Any electronics wizards out there who can reccomend the simplest way to do this. I can work somethingn out but might be messy. I've got one of these. Can I just use 2. With + On one input and - on the other in the hope it will switch on + and ignore the -. Will a -ve on the input damage it.

 

[PaulRainbow]

Any electronics wizards out there who can reccomend the simplest way to do this. I can work somethingn out but might be messy. I've got one of these. Can I just use 2. With + On one input and - on the other in the hope it will switch on + and ignore the -. Will a -ve on the input damage it.

I suspect that would last about 5 minutes, sorry.

What makes you think you need to use relays ?

What's the current rating of the new drive and which Autohelm model do you have ?

 

[KAM]

It's one of these. I compared the current draw when on load. The generic unit seemed about 1 amp higher. The motor in the generic unit is about twice the size and certainly looks better quality. I didn't want to risk blowing the output from the control head.

 

[PaulRainbow]

It's one of these. I compared the current draw when on load. The generic unit seemed about 1 amp higher. The motor in the generic unit is about twice the size and certainly looks better quality. I didn't want to risk blowing the output from the control head.

Can't read the model.

Which drive did you have ?

What drive do you have now ?

You're not making it easy....

 

[dgadee]

Pcnautic in Netherlands do a replacement drop in arm.

 

[KAM]

It's an ST4000 control unit. The existing rams have no identification. They are the old red and black Autohelm style. The generic has no spec other than speed and thrust that I can see. It's an interesting project. If I can't get it going I'll go for one of the Pcnautic ones dgadee has pointed out which I hadn't seen before. The drive unit looks very similar but 8x the price. I like to carry 2.

 

[KAM]

The Pcnautic looks quite fast in the video.

 

[PaulRainbow]

It's an ST4000 control unit. The existing rams have no identification. They are the old red and black Autohelm style. The generic has no spec other than speed and thrust that I can see. It's an interesting project. If I can't get it going I'll go for one of the Pcnautic ones dgadee has pointed out which I hadn't seen before. The drive unit looks very similar but 8x the price. I like to carry 2.

The ST4000 shouldn't be used with a linear drive, so you've done well to get away with it, they were meant for tiller or wheel pilots.

To operate it via relays you could use a pair of double pole relays. Connect the drive wire to both relay outputs in parallel. Connect the DC in to one relay one way and reverse polarity on the other. Connect both coil negative to -12v. Connect one coil positive to each of the drive wires from the ST4000.

Not sure how well it will work, never tried it, but i'd use good quality relays, they'll get a busy life.

 

[dgadee]

The ST4000 shouldn't be used with a linear drive, so you've done well to get away with it, they were meant for tiller or wheel pilots.

To operate it via relays you could use a pair of double pole relays. Connect the drive wire to both relay outputs in parallel. Connect the DC in to one relay one way and reverse polarity on the other. Connect both coil negative to -12v. Connect one coil positive to each of the drive wires from the ST4000.

Not sure how ell it will work, never tried it, but i'd use good quality relay, they'll get a busy life.

Are you sure:

Raymarine ST4000 Grand Prix Tiller Drive - W086

 

[dgadee]

The pcnautic info I got came from me setting up my PyPilot. The one I bought for my Seawolf has a number of wires, not just 2 power. No idea if you can use them with your system. I don't.

 

[PaulRainbow]

Are you sure:

Raymarine ST4000 Grand Prix Tiller Drive - W086

I said "The ST4000 shouldn't be used with a linear drive, so you've done well to get away with it, they were meant for tiller or wheel pilots."

The link you posted is for a tiller pilot, so i'm not sure of your point ?

Are you thinking the OP is using a tiller pilot, not a linear drive ?

 

[dgadee]

I thought he wanted a replacement linear arm. Apologies if I am causing confusion.

 

[PaulRainbow]

I thought he wanted a replacement linear arm. Apologies if I am causing confusion.

Might be me who is confused. I assumed he had a linear drive when he said "ram" and said so in post #2.

Never a mention of tiller pilot, perhaps the OP can clarify ?

 

[Graham376]

After many years heavy use my Autohelm ram has finally worn out. One of the planet gears has chipped. I've bought a cheap generic 12v ram off eBay to play about with. Has anyone else tried these. There seems to be plenty of thrust but a bit slower than the old one. The current draw is slightly higher than the Autohelm. I was thinking of trying a solid state relay to drive it and save damaging the control head. I'm not sure if the output is straight on/off or is it more sophisticated. Anyone else tried this.

Is this an ST4000 tiller pilot or inboard linear drive? If a linear drive, there's a heavy duty metal gear kit to replace the old plastic ones.

 

[KAM]

apologies for the delay. I usually get reminders. I called it a linear drive because that's what it is. It doesent have any identification on it. It came with my boat a long time ago and was attached to one of the old ST??? Black boxes with red, so called, waterproof seals. I always think of tillerpilot as the all in one units. I've tried to get replacemet gears but no joy. The motors are such poor quality I'm amazed they last as long as they do. Anyway pending buying one of the Pcnautic units, which look the business, I'm going to try diodes as per the attached which looks like a simple solution.

 

[KAM]

Just at the boat doing a trial fit. It's blindingly obvious that the slower more powerful ram will work by simply moving the tiller attachment point aft.

 

[PaulRainbow]

apologies for the delay. I usually get reminders. I called it a linear drive because that's what it is. It doesent have any identification on it. It came with my boat a long time ago and was attached to one of the old ST??? Black boxes with red, so called, waterproof seals. I always think of tillerpilot as the all in one units.

Just at the boat doing a trial fit. It's blindingly obvious that the slower more powerful ram will work by simply moving the tiller attachment point aft.

If it's attached to the tiller, it's a tiller pilot. Cockpit Tiller Drive | Boat Autopilots | Raymarine

In autopilot World a linear drive is one of these: Type 1 Linear Drive | Boat Autopilots | Raymarine

No matter though, hope the new "thing" works for you. Be aware though, that there are requirements for the angles between the drive and the tiller, moving the fixing points around might not comply with those. I'd try it where it is first.