New linear drive unit

[Kelpie]

Well this is going to hurt. Might be telling the family that Christmas is cancelled this year.

Our elderly Autohelm 5000 linear drive unit is very stiff and grumbly (aren't we all) and seeing as we're about to set off to the Caribbean, I'm going to splash out on a new one. The existing one does still work so it will go on the shelf as a spare.

I need to do this asap, and I want to maintain compatibility between the new and old drive units, so I think the only question is whether to fit a type 1 or 2 Raymarine.

We're ~9t which is within the rating of the type 1. It's not an enormous increase in price for the type 2. Perhaps worth it if it means it will be more durable. But I've heard that the only difference is the motor itself.

Any thoughts?

And has anybody on here done this swap and can comment on any issues with compatibility or installation?

 

[PaulRainbow]

Well this is going to hurt. Might be telling the family that Christmas is cancelled this year.

Our elderly Autohelm 5000 linear drive unit is very stiff and grumbly (aren't we all) and seeing as we're about to set off to the Caribbean, I'm going to splash out on a new one. The existing one does still work so it will go on the shelf as a spare.

I need to do this asap, and I want to maintain compatibility between the new and old drive units, so I think the only question is whether to fit a type 1 or 2 Raymarine.

We're ~9t which is within the rating of the type 1. It's not an enormous increase in price for the type 2. Perhaps worth it if it means it will be more durable. But I've heard that the only difference is the motor itself.

Any thoughts?

And has anybody on here done this swap and can comment on any issues with compatibility or installation?

There are no compatibility issues with the linear drives. The ACU only has two wires connected to the drive, which change polarity depending on the direction of travel required. The Raymarine system doesn't have any feedback from the drive to the ACU so the ACU has no way of knowing what's at the other end. You can fit any drive, from any manufacturer and it will work fine.

 

[rotrax]

Kelpie - if you have the sort I had that failed on our Island Packet 350 some 14 years ago you might find it worthwhile stripping the little DC motor that drives the ram.
Unlike a proper brush box, the boxes that hold and guide the brushes dont have a slot for the spring to follow as the brushes wear.
I found the inside of the brush end of the motor full of carbon dust and the springs hard against the edge of the brush box, so not allowing full spring pressure contact between brush and commutator. A good clean up and a tweak of the end of the spring so it could push vertically fixed it once and for all.

I hope this helps. Have a great trip.

 

[Hoolie]

I think you should check your ACU has the output current necessary for a Type 2 drive. I think the info is still on the Raymarine legacy devices support pages. We have a Type 2 drive on our 8000kg boat and I don't think anything less beefy would really work.

 

[Kelpie]

Just to clarify, the existing ram works ok, no problems there. But trying to back-drive it when in standby is very hard. There is clearly a fault in the ram itself. It's very noisy and stiff, and goes through patches of higher resistance. Usually worse trying to pull it out (to the point where I can only just manage it). I think this points to a problem with the recirculating ball drive.

The clutch, motor, gears, and belt all seem fine.

 

[Blueboatman]

Just to clarify, the existing ram works ok, no problems there. But trying to back-drive it when in standby is very hard. There is clearly a fault in the ram itself. It's very noisy and stiff, and goes through patches of higher resistance. Usually worse trying to pull it out (to the point where I can only just manage it). I think this points to a problem with the recirculating ball drive.

The clutch, motor, gears, and belt all seem fine.

Before condemning the units internal gubbins.
It is worth detaching the ram from its attachment to the steering quadrant and verifying that the whole unit can in fact swivel freely on its swivel pins at the mounting block - They can seize (stainless pin, alloy casting ) which will produce the exact symptoms you describe too !

 

[Kelpie]

Before condemning the units internal gubbins.
It is worth detaching the ram from its attachment to the steering quadrant and verifying that the whole unit can in fact swivel freely on its swivel pins at the mounting block - They can seize (stainless pin, alloy casting ) which will produce the exact symptoms you describe too !

It's definitely the ram. I've got the drive unit sat on the chart table, the clutch, belt, and gears are removed. I can push and pull the ram by hand but it's very notchy and gets so stiff that I can barely move it in places.
Given ours plans I don't think I can do anything other than buy a new one at this point. And I'm worried that if I try to further disassemble the old one I'll end up with it not even useable as a spare.

 

[Kelpie]

Ouch. That's it ordered. Went with SVB as they had it in stock and a good price. Decided to stick with the type 1 drive because the old one lasted 30yrs+.

I'd better go and tell the boy that Christmas is cancelled...

 

[LadyInBed]

The ACU only has two wires connected to the drive, which change polarity depending on the direction of travel required.

Plus the two wires on a separate connector to operate the clutch. ?

 

[skipmac]

Plus the two wires on a separate connector to operate the clutch. ?

Sold my spare, spare (long story but ended up with three drives) and the buyer contacted me to say it didn't work. Said he could hear the motor turn but the arm wasn't moving. Asked him if he had connected the clutch wires. Never heard back.

Guess it's moot since the OP already bought but I replaced my type 1 with a type 2 without a problem but I did make sure the computer had sufficient power for the type 2. One caveat. There are two versions of the type 2, long and short stroke. The short stroke is equivalent to the type 1.

 

[PaulRainbow]

Plus the two wires on a separate connector to operate the clutch. ?

I said

The ACU only has two wires connected to the drive, which change polarity depending on the direction of travel required.

No mention of clutches, rudder reference sensors etc.

 

[PaulRainbow]

Sold my spare, spare (long story but ended up with three drives) and the buyer contacted me to say it didn't work. Said he could hear the motor turn but the arm wasn't moving. Asked him if he had connected the clutch wires. Never heard back.

Guess it's moot since the OP already bought but I replaced my type 1 with a type 2 without a problem but I did make sure the computer had sufficient power for the type 2. One caveat. There are two versions of the type 2, long and short stroke. The short stroke is equivalent to the type 1.

Only dimensionally the same.

 

[sailaboutvic]

Some how I don't think Kelpie as the ACU unit but the older raymarine computer.

 

[skipmac]

Only dimensionally the same.

Dimensionally to me indicates only the physical size and/or shape of the unit. I think it worth mentioning that both type 1 and 2 (except the long stroke version) have the same stroke length of the arm and also the same response rate. The only difference is the higher power of the type 2 and of course the corresponding higher power draw.

 

[Kelpie]

Some how I don't think Kelpie as the ACU unit but the older raymarine computer.

I've got a Smartpilot X30 which is clearly much newer than the drive unit. Looks like the whole system was upgraded, except the drive unit itself.

 

[Graham376]

I think you should check your ACU has the output current necessary for a Type 2 drive. I think the info is still on the Raymarine legacy devices support pages. We have a Type 2 drive on our 8000kg boat and I don't think anything less beefy would really work.

Type 1 works fine for us over thousands of miles, boat 38ft and somewhere between 8 & 9 tons. Usual problem with old ones (IIRC pre-1996) failing is the gears and there's a service kit available. Raymarine Linear Drive Heavy Duty Gear Kit - N021 - Hudson Marine Electronics

 

[LadyInBed]

No mention of clutches, rudder reference sensors etc.

When you said "The ACU only has two wires connected to the drive"
I thought the "drive" you were refering to was the Linear Drive Unit, obviously nothing to do with the rudder reference sensors etc.
The Clutch is housed inside the LDU, so the LDU has four wires to it from the ACU.
Maybe you ment to say "two connectors connected to the drive" and should have made mention of clutch. ?

 

[PaulRainbow]

When you said "The ACU only has two wires connected to the drive"
I thought the "drive" you were refering to was the Linear Drive Unit, obviously nothing to do with the rudder reference sensors etc.
The Clutch is housed inside the LDU, so the LDU has four wires to it from the ACU.
Maybe you ment to say "two connectors connected to the drive" and should have made mention of clutch. ?

Yawn !

 

[Hoolie]

I've got a Smartpilot X30 which is clearly much newer than the drive unit. Looks like the whole system was upgraded, except the drive unit itself.

I have an SPX30 that's designed to drive a Type 2 unit. If you manage to acquire a spare Type 2 you'll have no problems driving it!

 

[Blueboatman]

What is a working 30 yr old type one worth ?