New Autopilot - CPT vs Raymarine EV100

[jacktheflyer]

I installed the EV100 and ST4000+ as an interim solution on a 12m Cat which was nominally right on its limitations and practically beyond it. Its still going today. There are some issues with the ST4000+ wheel drive which I've resolved over time but the EV100 is streets ahead of the previous Raymarine autopilot.

[sklitzky]

CPT works great on my Ericson 35-3

[sailorchic34]

I rolled my own Raspberry PI autopilot for $120 in parts. I was going to use Seans code, which is really pretty well thought out and has lots of features. I of course wanted a bit more of a challenge so wrote my own after learning Python. A fun project.... for an engineer

I added a plug in the old autohelm 3000 I use so I can switch between my home, er boat brew autopilot and the autohelm. I believe Sean was going to sell a kit of two boards, but not sure where that is. His has lots of bells and whistles and interfaces with opencpn, even offers a wireless control and or headless as well.

The CPT ia robust, but is more in line with the autohelm 3000 or 4000. It does not know the course bearing only flux readings that it uses to move the motor back and forth. So it's not really networkable.

[SV Simple Life]

We are massive fans of the CPT.

We used our 1985-vintage $400 unit on our 60ft wooden powerboat (38tonnes) for the first 2500 miles of our journey from Canada to Panama. When we swapped boats to a Tayana 37, we took it with us. Covered the next 2000 miles without a blink. Midway through, the guys at CPT rebuilt the head and motor for a very reasonable charge, and it works like new every day.

The most reliable piece of kit on the boat.

[hpeer]

A PyPilot is an autopilot control head. It has a compass sensor, 9 axis gyro (?), and takes a GPS heading. It does not have a drive unit so it needs to be mated to a ram (such as sold by Pealigic) or wheel drive unit (CPT).

The reason I’m fussing with the CPT/PyPilot interface is because we have a steel boat which totally mucks up the compass heading, very non linear. Some headings are just very hard to hold. I’m hoping the GPS heading will work better.

[a64pilot]

GPS is positional only, no heading.
GPS can provide a track, have to be moving, but no heading.
Heading requires some form of heading sensor, gyrocompass, or magnetic compass etc.
I’m sure there are GPS units with heading sensors built in

[Bill O]

Originally Posted by hpeer

A PyPilot is an autopilot control head. It has a compass sensor, 9 axis gyro (?), and takes a GPS heading. It does not have a drive unit so it needs to be mated to a ram (such as sold by Pealigic) or wheel drive unit (CPT).

The reason I’m fussing with the CPT/PyPilot interface is because we have a steel boat which totally mucks up the compass heading, very non linear. Some headings are just very hard to hold. I’m hoping the GPS heading will work better.

Besides the computer (Rpi) w/the 9 axis IMU, the pypilot needs a motor controller to run whatever type of drive unit you are using for a tiller, wheel (CPT or wiper motor) or below deck (electric or hydraulic).

Course heading can be done by compass, GPS (and set up routes) and wind (if interfaced).

Since Sean hadn't done a below deck hydraulic drive before, he did extra work for our large hydraulic (heavy duty controller) and wrote programming that is now embedded for a rudder feedback sensor. We think his work is exceptional and he continues to upgrade the pypilot software that is embedded in OpenPlotter (an easy download for people who don't want to learn Linux or programming). We are totally not programmers, but learned just enough to be dangerous. It's actually quite fun using cutting edge technology!

Hpeer, maybe you already looked at the video linked in #15, but showed that the pypilot worked w/ the CPT on a metal boat as well as w/a wiper motor. If I remember correctly the wiper motor was more efficient than the CPT motor. (His program allows one to monitor energy usage, thus can adjust gain settings to maximize efficiency or adjust sails if needed). The wiper motor could also be backup to the CPT drive if one wanted to carry a spare.


Bill O.

[jefndeb]

Well IMO, I upgraded from the ST4000 Plus to the EV-1000 and I can say that it really did much better dealing with swells. Its new heading sensor is very accurate and the system has different settings where you can select how tight you want it to hold a course, I think the settings were Performance, Cruising and Leisure...if you wanted to reduce battery use, the leisure setting would be good as it would not drive the motor as much, I installed the system myself, was pretty easy and I sold the ST4000 for $700, so in the end the upgrade was very good to the wallet!!!!

[Bill O]

We set up most of our nav. computer (RPi) and most of the items can be purchased separately (not from Sean), but I will say it's hard to beat his pricing that he has on his store front for the pypilot components.

Literally for ~$180 (total) one could have the controller components for an AP. Still need to have drive unit depending on tiller, wheel, etc., but again the wiper motor is relatively very inexpensive compared to a commercial system. An added benefit is he QCs his product before it shipped out. This makes an AP affordable for almost anyone.

We've directly seen Sean do all the work for his AP and think it really deserves a good look as it performs (possibly better) than the commercial systems that sell for $1.5K and up. One reason it's possibly a better product is you can actually set various internal gains to customize the AP setting to your boat vs. someone else setting up an algorithm for some unknown boat, so then you only have 3 preset gain settings to choose from. Guess that works for some, but the presets don't always work well for all boats.

Will say the packaging isn't the prettiest, but it is functional and very small. All our components are below deck, connected by wifi and data can be sent to what ever electronic device you would want (w10 tablet, android, etc.)

We looked at a lot of AP systems for our large displacement sailboat when we were redoing our old AP. Until a couple of years ago I had no idea or ever heard of what a RaspberryPi was or how powerful a small computer could be w/a casing slightly larger than a deck of cards. To us, it made sense to go w/pypilot instead of a commercial AP.


Bill O.

[a64pilot]

Originally Posted by Bill O

Besides the computer (Rpi) w/the 9 axis IMU, the pypilot needs a motor controller to run whatever type of drive unit you are using for a tiller, wheel (CPT or wiper motor) or below deck (electric or hydraulic).

Course heading can be done by compass, GPS (and set up routes) and wind (if interfaced).

Since Sean hadn't done a below deck hydraulic drive before, he did extra work for our large hydraulic (heavy duty controller) and wrote programming that is now embedded for a rudder feedback sensor. We think his work is exceptional and he continues to upgrade the pypilot software that is embedded in OpenPlotter (an easy download for people who don't want to learn Linux or programming). We are totally not programmers, but learned just enough to be dangerous. It's actually quite fun using cutting edge technology!

Hpeer, maybe you already looked at the video linked in #15, but showed that the pypilot worked w/ the CPT on a metal boat as well as w/a wiper motor. If I remember correctly the wiper motor was more efficient than the CPT motor. (His program allows one to monitor energy usage, thus can adjust gain settings to maximize efficiency or adjust sails if needed). The wiper motor could also be backup to the CPT drive if one wanted to carry a spare.


Bill O.

I’m pretty sure that the motor drive for the CPT is a Bosch OTR truck wiper motor, I’ve read it’s actually a 24v motor being driven by 12v.
A less powerful motor would likely use less power, but provide less torque

[Bill O]

Originally Posted by a64pilot

I’m pretty sure that the motor drive for the CPT is a Bosch OTR truck wiper motor, I’ve read it’s actually a 24v motor being driven by 12v.
A less powerful motor would likely use less power, but provide less torque

Not sure where Sean has the specs for the wiper motor he used, but it was a one used for a truck (heavy duty). Just like any electric driven wheel AP, it would need to sized appropriately and may not be able to handle all conditions. This where we felt the below deck hydraulic drive would do better.

Also I'm fairly certain his controller can be configured for 24V, besides 12V.



Bill O.

[hpeer]

Originally Posted by a64pilot

I’m pretty sure that the motor drive for the CPT is a Bosch OTR truck wiper motor, I’ve read it’s actually a 24v motor being driven by 12v.
A less powerful motor would likely use less power, but provide less torque

Earlier ones were 12vdc but at some point they went to 24vdc to get more torque.

I don’t know what they are using in the most recent units. I think the Bosh units, which had a nifty and confident 90° joint, are mfg dicontinued. I’d be pleased to be proven wrong.

[brownr377]

Thanks Bill, that's rad! I'm warming up to the idea of PyPilot. I've got a board with Openplotter installed that I need to get back to messing with looks like.

Well now I'm thinking, and that's a dangerous thing for me. But I can just muck about with pypilot using my current ST4000 wheel drive motor and see how that works out, costs me almost nothing.

I still am thinking longer term on the CPT, the Raymarine wheel drive is just a little weak for my taste, that's my biggest sticking point on the EV100, I'm convinced it's a great control system but the drive unit is the exact same as the ST4000 and they don't have any higher torque options unless you go with a below deck install.

-Reuben

[Pete7]

Originally Posted by brownr377

I still am thinking longer term on the CPT, the Raymarine wheel drive is just a little weak for my taste, that's my biggest sticking point on the EV100, I'm convinced it's a great control system but the drive unit is the exact same as the ST4000 and they don't have any higher torque options unless you go with a below deck install. -Reuben

I think you have the grey ST4000+ one which dumps the ball bearings out if you take it apart. Mine is too new so haven't had to do that yet.

However, I did play around with 3 of the older black ones to build one good one. Two were worn out with serious mileage, but one showed promise. There are some YT videos of the rubber wheels upgrade from screw to bolts that was very successful. Add to the fact that the black ST4000 wheel drives have brass cogs in the gearbox I thought it a much better built drive and easier to work on. The grey one has flimsy cases.

If you can find a black wheel drive in good condition, that would be worth fitting if your grey one is on its last legs.

Note: there is a small steel pin on the end of the electric motor to stop it turning in the housing. Don't push it in or you will never get it out of the motor. Don't ask how I know.

Pete

[siamese]

I talked with CPT prior to purchasing their unit, as the install was going to be difficult on my Catalina 28, and none of their adapters were going to work. In the course of my conversation with them, I learned that they no longer use the Bosch wiper motor. Which isn't to say the new motor is better or worse, but the Bosch was dropped.

I've had a couple Raymarine systems, and found them to be okay, but somewhat underpowered.

I went with CPT on my Catalina for two reasons:
-- When under power, the Cat 28 wants to turn to port. Take your hands off the wheel at cruising speed, and the boat will immediately go into a spin. There's always some pressure felt on your hands as you steer, and I wanted a more powerful unit to more easily overcome this torque. Under sail, the 28 doesn't have this characteristic.

-- As I was deciding to go Raymarine or CPT, I was reading many stories about the complexity of the Raymarine install, the poor documentation that comes with it, and the lack of tech help from Raymarine. As I was planning to install myself, I wanted it to go smoothly and get it right the first time. All who have successfully installed the Raymarine can chide me.

note: When I called CPT (at least a couple times) I got a knowledgeable person who I believe was one of the owners. That's service.

Usage:
The CPT control is a far cry from the Raymarine. Of course, it's a totally stand-alone unit, which will eliminate if for probably most users. It actually uses electronic gyroscopes for at least part of it's directional capability. So, before putting it on a heading, you have to maintain that heading for at least 30 seconds, or it will rather quickly start to drift off the desired course. After using it for one Michigan season, it also seems that if you correct the heading by punching in one degree increments, you need to let it get used to the new heading before tweaking it some more.

That said, for my purposes, I would buy one again. I had to design some special stainless mounts and have them fabricated (only about $200) but the install is a clean one, and it works for the way I sail.