Misbehaving Neco

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May 15, 2012 at 16:26 #5891
Ronar M
Ronar M
Participant

Hi All,

Last winter I took out the final steering box from the lazarette. Too late I discovered that the thing to do is to remove the wooden divider that separates the lazarette from the area immediately ahead of it – that would have made the job easy. I took this panel out to replace the unit once it was refurbished.

It is not a Mathway unit but the other type (Forman). The guy at Mathway quoted £1300 (then there would be 20% tax on top) for a new aluminium top for the unit which was leaking oil from around the shaft. Instead I got a local garage to remove the top (they had to drill out the allen bolts) and another local company to replace the bearings and oil seals (they had declared the aluminium top perfectly servicable). The whole job cost £650 including tax.

Anyway, that is not the problem. In my innocence I did not mark the shaft or lock the wheel when I dismantled the steering gear and since reassembly my Neco autohelm is not happy (keeps making the boat circle to port). Clearly I have reassembled it in a different position and the whole thing is out of synch with itself. I have had the idea of releasing the shaft from the final gearbox and, with the boat moored alongside, set the autohelm to coincide with the steering compass before switching to autohelm and letting it settle itself before reconnecting the steering. I have tried this once but sadly Neco was having an off day and wouldn’t work at all. I will try it again when it is in a better mood BUT does anyone out there have a better idea or have experience of this problem? I have the original instruction manual but it doesn’t make much sense to me.

Cheers, Trevor

May 15, 2012 at 18:37 #11621
Van
Van
Participant

Hi Trevor,

If you let it, would the Neco steer you in a giant circle? Makes me wonder what kind of control circuit logic it uses.

The instruction manual section 4.1 describes “Lining up on Installation” – this is probably what you mean does not make sense. It sounds a lot like what you are suggesting, but they don’t disconnect at the final gearbox, instead they disconnect the chain from the drive unit.

Note that they disconnect the compass cable from the system during this set up. This will make the drive unit run to its neutral position (so the instructions seem to indicate). Then they set the rudder amidships, and at that point reconnect the drive unit to the chain (step 6).

If you do align the Neco with the steering by aligning it with the compass heading, it would seem you are presuming that your compass heading was correctly calibrated. Also, when you switch on the autohelm, it will either not move (it’s happy) or it will never settle until you move the Neco dial to exactly coincide with the steering compass. Of course, you also need to make sure the rudder is held amidships until you reconnect the gearbox.

Good luck!

Van

May 16, 2012 at 10:41 #11631
Ronar M
Ronar M
Participant

Hi Van,

That is helpful. Thanks.

Yes, the unit was trying to put steer the vessel in a circle. Next time I am on board I will have a look at the instruction book again and see if I have the section you are referring to.

The Neco unit has never been correctly calibrated to the boat’s main steering compass; there was always a discrepancy which I have lived with. The Neco unit was about 10 degrees out.

Will keep trying

Cheers, Trevor

May 16, 2012 at 18:30 #11641
Van
Van
Participant

You can calibrate the steering compass by simply rotating the compass unit. It is held down by a couple of screws/bolts in slots so you can rotate it to adjust for errors like that. Not terribly accurate, but good enough.

May 19, 2012 at 22:23 #11651

IWanda
Participant

We had the Neco turn sharply to port and replaced the entire unit (found one new still in the box in Annapolis). Once installed it did the same thing. Only part not included with the new unit was the rudder feedback (small inexpensive part) since I Wanda has hydraulic steering. If you don’t have hydraulic steering then you will not have the rudder feedback which tells the Neco the position of the rudder and allows it to steer a correct course. We now have two Necos and keep a spare rudder feedback.
Good luck! Mary

May 22, 2012 at 14:32 #11681
michael bennett
michael bennett
Participant

I have replaced my Neco with a Simrad unit to drive the Series Shunt motor, and I have the old neco units for sale if anyone requires spares, send me an e mail for details.

Mike

(I am on holiday from 28/05 to 21/06)

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