CTP Autopilot problems

[Exile]

Originally Posted by hpeer

The “surgery” is more like removing a splinter, IMHO.

The drive connection is 2 wires: motor spin direction comes from the polarity of the wires. The AP reverses polarity to reverse motor spin direction. How hard the unit turns is determined by the amount of current supplied. Then there is how long it is supplied. But it matters not which controller (CPT, PyPilot, Pelagic) or which drive unit (CPT, ram, hydraulic motor) they all work the same.

I might be over reaching, there are probably units that work differently, but this is common amongst the units we are discussing here.

Disagreement? Questions?

Don't know enough to disagree, and have nothing BUT questions. I didn't want to sidetrack the thread but just happen to be in the midst of a steep learning curve as I contemplate how best to install a backup AP for my aging (pre-Navico) B&G. I'm only here because the (new) CPT has long been on my list, and seems to be the only wheel pilot I've read about that can handle a larger boat like mine. Unlike a64, however, I have a chain/cable steering system with a long run to the quadrant on my CC 47'er. So now I'm redirecting efforts at figuring out a backup to my existing below decks AP.

In my case I just had the T2 ram rebuilt so it's more about some "glitchiness" with my now 15+ year-old electronics that has me concerned, especially with the heading sensor/compass but can't really pin it down. I've been exploring the idea of a completely separate stand-alone controller such as Pelagic, PyPilot or perhaps even a new B&G/Navico (or other brand-name) AP computer with a new heading sensor, RRU, and control head. The new B&G kit would require at least a partial conversion to N2K which I don't relish doing but will eventually be required anyway.

I did manage to successfully install a Vesper XB-8000 with NMEA 0183 data now displaying wirelessly on my PC & devices so I'm not a total noob. This could be all I need for a PyPilot if I understood Bill O correctly. And what you've described above about mating an AP controller to an actuator -- whether it be a below decks ram, tiller actuator or wheel pilot, is exactly what I've been told by several mfgs. The only caveat is that the controller (brains) has to have sufficient amperage to power the drive unit (muscle).

In any event, reading, listening, and hopefully learning. But then you know what they say about those who gather a little bit of knowledge . . . .

[hpeer]

Completely understood. It’s a bit daunting and I’m no expert. Hopefully Sean will drop in here and Clarify things a bit.

[Exile]

Originally Posted by hpeer

Completely understood. It’s a bit daunting and I’m no expert. Hopefully Sean will drop in here and Clarify things a bit.

My sense is it's easier to accomplish for both myself and a64, in part for the reasons you describe. The difference is that it sounds like a64's CPT is his primary AP and his goal is to increase it's functionality by integrating it into his chartplotter/NMEA system. In my case, I want something solely as a stand-alone backup, and therefore want as little integration as possible.

[Bill O]

Originally Posted by hpeer

Now if you want it to work on a “plotter” you need to ask someone else but I think right now it just works with OpenCPN. That project is a bit down on my bucket list.

If you want OCPN, learn from my experience and just download OpenPlotter. It will be much easier to do the down load and then it all work through the plotter. Really wasn't that hard and works as well (maybe better) than spending the big $$ for the "name brand" system.


Bill O.

[Bill O]

Originally Posted by Exile

I did manage to successfully install a Vesper XB-8000 with NMEA 0183 data now displaying wirelessly on my PC & devices so I'm not a total noob. This could be all I need for a PyPilot if I understood Bill O correctly. And what you've described above about mating an AP controller to an actuator -- whether it be a below decks ram, tiller actuator or wheel pilot, is exactly what I've been told by several mfgs. The only caveat is that the controller (brains) has to have sufficient amperage to power the drive unit (muscle).

Sounds like you are totally capable to install a pypilot if you can hook up your AIS wirelessly. Again I'm not a computer geek and can put the system together (again look in my previous posts in this thread for the 2 links to the nav station and pypilot set up).
So for our AP set up, I ripped out a 40+ yr old AP and basically started from scratch. We installed one of the more powerful below deck hydraulic pumps made for recreational boats and use the high amp motor controller (pypilot) for this large reversing pump (30 amps max). Been running it for a few years and it been working well.
The actual "brain" is the pypilot programming and computer to run the motor controller.

The pypilot computer and the motor controller could be used as a back up to your AP.

Bill O.

[a64pilot]

Originally Posted by Exile

My sense is it's easier to accomplish for both myself and a64, in part for the reasons you describe. The difference is that it sounds like a64's CPT is his primary AP and his goal is to increase it's functionality by integrating it into his chartplotter/NMEA system. In my case, I want something solely as a stand-alone backup, and therefore want as little integration as possible.

You are correct it’s my primary. Original plan was to get a “real” below decks AP and the CPT as a back up as a windvane isn’t possible on my boat, so if I were to do a real passage I want a back up AP. The thought of hand steering for weeks is daunting to say the least. But the CPT works so well and especially since it’s power consumption is pretty much nothing it has me reconsidering why I’d want a complex, expensive power hog if it’s possible to get the CPT to track to a waypoint. It becomes even more attractive when you realize that if the CPT fails completely, say from a lightning strike that cooks it, all that has to be done to replace it is one electric plug and loosen four wing nuts, slip in the back up, plug it in tighten four wing nuts and you have a complete new autopilot to steer you. Now if a “real” one breaks it can be a big deal to rebuild or replace a ram that is below decks. Make up and or replace a hydraulic hose etc. and Lord help you if a lightning strike gets it.
It’s no big deal really but for example as I cross the Gulf Steam I’m having to add a couple of degrees to my CPT every few minutes as I begin get get into higher current and then of course when I’m coming out of it I’m doing the opposite

[Exile]

Originally Posted by a64pilot

You are correct it’s my primary. Original plan was to get a “real” below decks AP and the CPT as a back up as a windvane isn’t possible on my boat, so if I were to do a real passage I want a back up AP. The thought of hand steering for weeks is daunting to say the least. But the CPT works so well and especially since it’s power consumption is pretty much nothing it has me reconsidering why I’d want a complex, expensive power hog if it’s possible to get the CPT to track to a waypoint. It becomes even more attractive when you realize that if the CPT fails completely, say from a lightning strike that cooks it, all that has to be done to replace it is one electric plug and loosen four wing nuts, slip in the back up, plug it in tighten four wing nuts and you have a complete new autopilot to steer you. Now if a “real” one breaks it can be a big deal to rebuild or replace a ram that is below decks. Make up and or replace a hydraulic hose etc. and Lord help you if a lightning strike gets it.
It’s no big deal really but for example as I cross the Gulf Steam I’m having to add a couple of degrees to my CPT every few minutes as I begin get get into higher current and then of course when I’m coming out of it I’m doing the opposite

Your positive review of the CPT is consistent with what I've often read. Namely people buying them as backups who wind up using them as primary because of the low power consumption, along with the other benefits you described (it's reportedly quiet). I still may go that route, and I like the idea of installing the bracketry & wheel pulley but then stowing the drive & control boxes below unless needed. Whether used as backup or primary, what's also attractive is that it's a completely self-contained system for ~$2,000. Tough to beat, and even better if you configure it for course & wind steering. And in my case, what are the chances of both my primary below-decks AP and my chain/cable wheel steering breaking on the same passage? (don't answer that ).

[Exile]

Originally Posted by Bill O

Sounds like you are totally capable to install a pypilot if you can hook up your AIS wirelessly. Again I'm not a computer geek and can put the system together (again look in my previous posts in this thread for the 2 links to the nav station and pypilot set up).
So for our AP set up, I ripped out a 40+ yr old AP and basically started from scratch. We installed one of the more powerful below deck hydraulic pumps made for recreational boats and use the high amp motor controller (pypilot) for this large reversing pump (30 amps max). Been running it for a few years and it been working well.
The actual "brain" is the pypilot programming and computer to run the motor controller.

The pypilot computer and the motor controller could be used as a back up to your AP.

Bill O.

Yes, I need to look at your links again and take a better look at PyPilot. Thanks for the recommendation.

As for the Vesper installation, it was a good thing I wasn't doing it to make a living or my hourly rate would have been well below the minimum wage. In hindsight, of course, I don't understand what the big deal was, except I was venturing into some yet unknown waters integrating it with my existing NMEA 0183. Great learning experience. The Vesper also operates as the wired-to-wifi multiplexer(?) you referenced earlier (hope I got my vocab right), so it sends all my instrument data wirelessly to PC's and devices with compatible apps. I mostly use Coastal Explorer but I believe it may also work with OpenCPN. If it will also transmit AP data to the PyPilot then that could wind up being the cheapest & easiest solution of all. With aging electronics and intermittent "glitches," it seems hard to pin down which component of the AP system is causing the problem. I believe the ram itself, however, is OK.

[Stu Jackson]

Originally Posted by a64pilot

.........................but for example as I cross the Gulf Steam I’m having to add a couple of degrees to my CPT every few minutes as I begin get get into higher current and then of course when I’m coming out of it I’m doing the opposite

Hey, a64, you did read Dockhead's Course to Steer topic, didn't ya???
http://www.cruisersforum.com/forums/...ad-115361.html

[a64pilot]

Originally Posted by Stu Jackson

Hey, a64, you did read Dockhead's Course to Steer topic, didn't ya???
http://www.cruisersforum.com/forums/...ad-115361.html

I will say that I can’t see any difference in an aircraft flying to a navaid in a cross wind and a boat steering to a waypoint with cross currents.
So I’m going to steer the boat the same way I steer an aircraft.

To not do so means you know with absolute accuracy the exact speed and current direction, something which I don’t believe.
How can you calculate for an unknown?

Now maybe back in the day before your actual course over the ground could be determined then that was required, but now we can determine with absolute accuracy what our course over the ground is, just like an aircraft flying to or away from a VOR has been able to do since long before my birth.
See I believe that the shortest distance between two points is a straight line. Besides it requires no fancy calculations based on guesses of what the current is.

[motthediesel]

I'm new here, and I found this thread in the course of my "autopilot" searches.

I have an Albin 27 trailer/trawler, and I want to add an autopilot. The boat is equiped with a Teleflex cable steering setup, and I do not want to convert it to hydraulic. I would like to use this Octopus powered helm unit: https://www.defender.com/product.jsp?id=4063937 but of course I will need a compass/control unit to pair it to.

I had not heard of the "PyPilot" before, but it seems like it might be an ideal solution. The Octopus drive draws around 1.5A, with a max of 5A, so it would seem to be well within the capability of the motor controller. Does anyone see a reason why this would not work?

Tom

[seandepagnier]

Originally Posted by a64pilot

I will say that I can’t see any difference in an aircraft flying to a navaid in a cross wind and a boat steering to a waypoint with cross currents.
So I’m going to steer the boat the same way I steer an aircraft.

To not do so means you know with absolute accuracy the exact speed and current direction, something which I don’t believe.
How can you calculate for an unknown?

There are various techniques for crossing a current. The optimal route depends on the speed of the current in that location which you may or may not know.

pypilot follows routes by being instructed to hold a particular gps course. It is up to the chart plotter (opencpn) to vary this course to follow a route or other function.

The gps course in pypilot is held by low pass of gps course and high pass of compass course unless using the wind pilot. The wind pilot follows gps courses by high pass of wind sensor (follow wind shifts) and low pass of gps and is also immune to magnetic distortions. There are other possible ways to hold a gps course not yet implemented.

The autopilot route plugin for opencpn generates the nmea0183 APB messages that instructs pypilot which gps course to hold. This is computed by the active waypoint or route. The plugin has a special mode "route position bearing" which does not steer to a waypoint but instead follows along a route. This gives continuous route following performance that is not different depending on how far you are from a waypoint. It gives better behavior when transitioning from one route segment to the next especially if the angle is large.

Crossing a current if the data is known with high resolution, the weather routing plugin can compute the optimal route which can greatly vary depending on conditions. In many cases the data needed is not sufficient, or the best route is still basically a straight line as mentioned above.

[a64pilot]

You know a smart guy, smarter than me could take that PY Pilot and connect it to a CPT drive and for wheel steered boats, and really have something that works and is very miserly on power.
It’s bad because in storage I bought a Panasonic toughbook to run OpenCPN on, and while it’s not the best and brightest screen it seems to work well and of course is supposed to be rugged.
With the way Radar etc can also be connected to Open CPN a smarter or less lazy guy than I am could easily have it seems a more capable system for far less money

[hpeer]

A64, it really, really is only 2 wires.

[MartinR]

Originally Posted by hpeer

A64, it really, really is only 2 wires.

Yes, in principle it is only two wires. In reality you want to be able to switch between the pypilot controller and the CPT controller and this means 4 wires. It is a very simple thing to do.

I drilled a hole in the bottom of the CPT drive unit and installed another watertight cable gland.



A 4*1.5mm cable is connected to A) the drive motor B) the CPT motor controller output. The other endof the cable is connected to two DPDT switches, that lets you choose controller and supplies it with power. A single 4 pole DPDT switch would be better, but I took what I had. You can either have this switch in the CPT drive unit, or like me outside somewhere in the cockpit.



The rest is just installation of the tinypilot unit and motor controller. Pretty straightforward. My tiny pilot is situated next to the Nav screen.



The whole process took me about 2 hours, most of the time spent pulling a data cable from the Nav station to the motor controller.