Strong pull on port

[PineyWoods]

In my humble opinion... there's a website that lists all those things.

Damage an autopilot? Heck, I thought that's what they were for! What autopilot? What do you mean by "then let go?"

Seems pretty obvious in his reports: the wheel - ergo the typical wheelpilot belt drive AP motor - has a strong torque bias load under higher RPM motoring, and I Imagine the belt slips it's cogs when it "lets go" - disengages without having the belt tensioner released. And yes, an AP motor working under a high load can overheat and definitely sustain damage. And also the belt, particularly if old.
Pete

 

[Stu Jackson]

Seems pretty obvious in his reports: the wheel - ergo the typical wheelpilot belt drive AP motor - has a strong torque bias load under higher RPM motoring, and I Imagine the belt slips it's cogs when it "lets go" - disengages without having the belt tensioner released. And yes, an AP motor working under a high load can overheat and definitely sustain damage. And also the belt, particularly if old.
Pete

Yes, Pete, but those symptoms could well be from simply a worn belt and lack of preventative maintenance from the skipper.

 

[PineyWoods]

Yes, Pete, but those symptoms could well be from simply a worn belt and lack of preventative maintenance from the skipper.

True, Stu, but the AP motor strain in fighting a constant torque bias (that wears out the skipper!) needs to be corrected with a simple counter-acting force such as a bungee cord.

The Autohelm wheelpilot motor on our '93 F-P 37' cat gave up after about 19,000 mainly offshore NM's on a particularly rough leg from the Cape Cod Canal to Maine, and was too hot to touch. It also killed the controller head as the shorted out motor drew too much current through it - due to my stupidity in not installing the included 10A inline fuse with it and depending on the panel breaker of unknown, but apparently much higher rating. So my spare motor was for naught, and had to buy a whole new replacement AP in Maine, as the control panel was not sold separately then (1999). It is extraordinary, though, how durable these little units can be if properly installed!

My current old C-30 is the 4th wheelpilot equipped boat I've owned, and just disassembly, cleaning out with water (boat had been raced extensively on SF Bay), and the prophylaxis of a new belt has kept it working smoothly.
Pete

 

[Stu Jackson]

Understood, Pete. I don't disagree.
Another technique he could use is to reset the gain / response to minimize movement. Heck, we did that coming up the coast. If the motor isn't instructed by the control head to move often... follow the fuzzy logic...

 

[Benny17441]

I think I may have experienced what your saying in a different boat. It is a very strong pull to port and nothing that would resemble a normal pull. In my case the engine was not reaching full RPM and it turned out to be a fouled prop in need of cleaning. If it does not happen when under sail then it sounds to me like you could have a fouled prop. First have it cleaned as well as the bottom of the boat. If the problem persists have it removed and take it to a prop shop to have it trued and balanced. Don't forget to also check that the shaft is turning freely.

 

[MORNING LIGHT]

In my humble opinion... there's a website that lists all those things.

Damage an autopilot? Heck, I thought that's what they were for! What autopilot? What do you mean by "then let go?"

When I engage the AP. It will work for 1- 2 minutes then start to go on port also. I was wondering if it could be too much pressure from the wheel ?

 

[MORNING LIGHT]

I think I may have experienced what your saying in a different boat. It is a very strong pull to port and nothing that would resemble a normal pull. In my case the engine was not reaching full RPM and it turned out to be a fouled prop in need of cleaning. If it does not happen when under sail then it sounds to me like you could have a fouled prop. First have it cleaned as well as the bottom of the boat. If the problem persists have it removed and take it to a prop shop to have it trued and balanced. Don't forget to also check that the shaft is turning freely.

The boat has been hauled out now and the prop is clean and the hull as well. I asked Catalina for specs for the prop and I will have some tests to conduct at spring to make sure the prop on the boat is the right one. Thanks

 

[MORNING LIGHT]

My friend had a C28 Mk I, but with the more common M3-20 engine (18hp). He experiment with different props, and found that a 13X8 2 blade prop to be just about right. Did not effect the left pull. If you do have a 25XP, you will probably need more prop pitch. His boat did exactly as you describe. It is normal to have some left hand pull with a right hand prop, but the C28 has a lot more than most. My friend said that the MkII had a different rudder with less area on the leading edge and more on the trailing edge to make it pull less. Don't know if that is true. I made a 23 mile trip on that boat and ended up tying a heavy piece on bungee cord to a short piece of line. I tied the bungee to the top of the wheel and secured it to a cleat on the combing to make the helm neutral. Otherwise, I couldn't let go of the wheel for a second without it slamming to the left stop. Not pretty, but it works.

Thanks, I sent email to Catalina who sent me a test sheet to conduct on the boat at spring to make sure I have the right prop for the boat. From, there, I will advise.