What autopilot to use when the CPT won't work?

[svsanctum]

After a lot of research and agonising, I recently purchased a CPT autopilot and installed it. Unfortunately it would not work on my boat (when I set the heading and the boat wandered, the CPT corrected in the direction it wandered and continued correctiing in that direction until we had done a full circle). The CPT people could find no problem with their equipment and decided it was because there was too much magnetic interference on my boat. They refunded me the purchase price (but not the $250 total I paid in freight). However I am unable to demonstrate significant magnetic interference. The original Simrad autopilot that was installed when I bought the boat worked in reasonable conditions. Has anyone had any experience?

My dilemma now is what to install, having decided that the only real option for me was he CPT unit. Working conditions below the cockpit are very cramped and difficult for installing and maintaining a below decks unit, not to mention the cost. I suspect that my boat must displace 7.5 tons (design displacement is 6.25 tons) which is the upper limit for recommended for the Raymarine type wheel pilots, so I would not expect them to handle the boat in other than calm conditions.

Any suggestions?

[hellosailor]

" too much magnetic interference on my boat. "

And....
...Is your boat a steel hull?
Do you have an iron ballast?
Are you running a high power pirate radio station aboard?

Or were you just trying to install the fluxgate compass next to the engine?

Until you find out why the last one didn't work, there's no reason to think any other one would work.

[Panope]

I use a Raymarine wheel pilot on a 7+ ton boat with a barn door type rudder. The unit will steer the boat when fully powered (rail in water) and with considerable weather helm. I do not sail in open ocean but I suspect that continuous operation in large seas will quickly wear-out the rather flimsy drive gears/belt. That said, the wheel pilots are so cheap, you could have a couple spare units on board.

And welcome to CF.

Steve

[barnakiel]

I do not know CPT but all other brands work fine if they are installed and commissioned fine.

Get the service people to work. If they cannot get their own product work ... oh, well.

b.

[onestepcsy37]

When I first started using my CPT on my ten ton full keel cutter I also had trouble with the boat wandering off course. But that was before I read the instruction book.

What I found was that you are supposed to adjust rudder and deadband to the prevailing conditions. Only trial and error will tell you what settings to use for your particular boat in various conditions. I found that generally, on my boat anyway, I was trying to steer too close a course while not allowing it to use enough rudder to correct the course. I even prepared a cheat sheet to remind me of the different settings - downwind, upwind, crosswind, flat seas, rough seas, etc.

Did you try adjusting deadband and rudder? Did Jeff coach you through this?

[a64pilot]

Usually you can use a hand held compass to determine if magnetic interference is an issue, I believe I read about this on CPT's website.
There are some troubleshooting measures you could try, but I believe if you go to an autopilot with a remote mounted flux gate compass, you won't have any problems
$250 in shipping? What did you overnight the thing?

[svsanctum]

Thanks for all the replies.

Boat is GRP with lead ballast and I was not running the HF radio. I tried various heading sensor locations and checked for magnetic interference using several handheld compasses.

Jeff from CPT did coach me through by email and sent me a hiking ompass to test for interference.

I did try adjusting deadband and rudder settings. And I did read the manual (even before ordering!).

Anyone else successfully using a Raymarine wheel pilot on 7.5 ton boat?

[olaf hart]

Depends.

Is the steering light?
Are the sails balanced?
Is there a following cross sea?
Is it blowing hard?
Phase of the moon.
Are the stars in a Raymarine alignment?

If you use the newest ones with a computer and flash gyro, they are better.
They also improve if you fit a rudder position indicator.

But there is no way it will work when you need it most, in a big blow with a big sea, at night when everyone is throwing up and exhausted.

[onestepcsy37]

Originally Posted by svsanctum

Thanks for all the replies.

Boat is GRP with lead ballast and I was not running the HF radio. I tried various heading sensor locations and checked for magnetic interference using several handheld compasses.

Jeff from CPT did coach me through by email and sent me a hiking ompass to test for interference.

I did try adjusting deadband and rudder settings. And I did read the manual (even before ordering!).

Anyone else successfully using a Raymarine wheel pilot on 7.5 ton boat?

Glad to read that you read the manual first. Also glad to read that Jeff coached you through. My boat is also GRP and lead ballast, but minimal electronics.

May I ask what make and model your boat is?

[svfraidknot]

i have a ray marine autopilot with the small belt around my wheel .. my boat 42 foot solaris is way heavy no idea the weight but my autopilot works fine running both motors ,, one motor if not a lot of cross current ,, but under sail it goes crazy .. motor sailing it will work if steady wind ..

[capttman]

Originally Posted by onestepcsy37

When I first started using my CPT on my ten ton full keel cutter I also had trouble with the boat wandering off course. But that was before I read the instruction book.

What I found was that you are supposed to adjust rudder and deadband to the prevailing conditions. Only trial and error will tell you what settings to use for your particular boat in various conditions. I found that generally, on my boat anyway, I was trying to steer too close a course while not allowing it to use enough rudder to correct the course. I even prepared a cheat sheet to remind me of the different settings - downwind, upwind, crosswind, flat seas, rough seas, etc.

Did you try adjusting deadband and rudder? Did Jeff coach you through this?

Yup I experienced the same thing and 20 years later and one rebuild its still works like a champ.. Dead band was my downfall when I started with it. I'm 18 tonnes



Sent from my iPhone using Cruisers Sailing Forum

[onestepcsy37]

Originally Posted by capttman

Yup I experienced the same thing and 20 years later and one rebuild its still works like a champ.. Dead band was my downfall when I started with it. I'm 18 tonnes

When I first started using the CPT my reasoning was that I wanted the AP to immediately correct for the slightest deviation off course and to use the minimum amount of rudder so as to have little effect on speed. I never took sea state into account. I suppose on a completely flat sea with light wind and on a broad reach that might work, but I never had a day like that.

Nothing like reading the manual and getting some sea time in varying conditions to smarten you up. OTOH the OP seems to have done all that. Wonder what kind of boat he has...