Rule 52, Manual power.  Frequently amended by NOR/SI's in shorthanded racing. 

Special prescriptions from clubs may allow use of autopilots either for short-handed or now with RORC for any of their races

Sean, the issue is often covered in the class rules. Here is a example from the IMOCA class rules;

C.2 SERVO POWER AND MANOEUVRING
(a) RRS Rule 52 is replaced as follows :
« The boat’s standing rigging, running rigging, sails, spars, foils or daggerboards shall be adjusted and operated only with the power provided by the crew. Only the keel, the rudders and the filling, transferring and emptying of the ballast tanks may be controlled and adjusted by power provided from other sources. »

Hope this helps.

Thank you all - I presumed it was there but couldn't see what rule it was

When I saw the initial question above, it immediately made me wonder what people would respond... but I am still confused after reading the responses so far. Let me explain: most autopilots have many inputs (wind direction being the most relevant to sailboats) only one control: powered rudder movement. R52 says that power to adjust and operate the rudder can come from other source different from crew. So I think the initial question must be decomposed into the "auto" and "pilot" parts:

So I think question #2 remains, and I think it was what Sean Hanley was initially asking about, right?
I am eager to hear opinions now...

Thank you.

I usually use an auto-tiller on a reaching/broad-reaching leg when sailing my day-boat solo. How else am I supposed to make a cup of tea?

RRS 52 pretty clearly prohibits electromechanical autopilots - ERS E.1.2(j) specifically identifies the rudder as a hull appendage. 

But would it apply to windvane self-steering? I kind of think not...

RORC NoR is clear. 1.5.4 1.3 Automatic and wind-vane devices for steering are permitted (this changes RRS 52)’

IRC rule 15.1 disapplies rule 52 in its entirity where racing is conducted using IRC handicaps.

Does anyone know how ORCi handles it?

Tim Hohmann

Is the power for wind vane steering provided by the crew?

I don't think so.

Rule 52 doesn't say power can't be provided mechanically, it says power shall be provided by the crew.