I'm looking to contact someone who has fitted, or owns, a Hunter 33 with a Raymarine Autopilot. I'm looking to replace the "Wheel Drive" with a rotary drive, similar to the setup on the Hunter 42 I have seen. Any advice will be appreciated.
Hunter 33 Raymarine Autopilot
- Thread starter Ian Thailand
- Start date
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 24,453
No idea of the age of your Hunter, so the information is based on the popular Hunter 33 built between 2004 and 2011. This boat was most often built with a Lewmar Rack and Pinion steering system. It is not at all like the Hunter 42 that uses a chain drive system.
The idea of a rotary drive system would be a complicated redesign of the Hunter 33 control mechanism. Essentially, you have a rotary system in the Wheel Drive AP. Your system rotates the wheel, which then transmits the motion ot the rack-and-pinion rotational system inside the binaccle. That is then converted to linear movement, which moves the rudder.
If your concern is the strength of the Wheel Drive AP to control your boat in open water, then you should look at the linear drive systems that attach directly to the rudder shaft. Raymarine makes one. It is their EV-200 system
www.raymarine.com
The idea of a rotary drive system would be a complicated redesign of the Hunter 33 control mechanism. Essentially, you have a rotary system in the Wheel Drive AP. Your system rotates the wheel, which then transmits the motion ot the rack-and-pinion rotational system inside the binaccle. That is then converted to linear movement, which moves the rudder.
If your concern is the strength of the Wheel Drive AP to control your boat in open water, then you should look at the linear drive systems that attach directly to the rudder shaft. Raymarine makes one. It is their EV-200 system
EV-200 Sail Pilot | Boat Autopilots | Raymarine
Evolution autopilot systems for mid-sized sailing boats with mechanical steering.
www.raymarine.com
Thank you so much for the info and the drawing, that looks like the unit in the pics and the boat age is about right. The boat is not nearby, so I am flying blind truing to suggest a way to fit a pilot. My customer has a Raymarine wheel pilot and wants to improve on it. I can see that I really need much more detail about the boat before I can offer any advice. Most of the boats using the Lewmar pedistal have wheel drives.No idea of the age of your Hunter, so the information is based on the popular Hunter 33 built between 2004 and 2011. This boat was most often built with a Lewmar Rack and Pinion steering system. It is not at all like the Hunter 42 that uses a chain drive system.
The idea of a rotary drive system would be a complicated redesign of the Hunter 33 control mechanism. Essentially, you have a rotary system in the Wheel Drive AP. Your system rotates the wheel, which then transmits the motion ot the rack-and-pinion rotational system inside the binaccle. That is then converted to linear movement, which moves the rudder.
View attachment 236408
If your concern is the strength of the Wheel Drive AP to control your boat in open water, then you should look at the linear drive systems that attach directly to the rudder shaft. Raymarine makes one. It is their EV-200 system
EV-200 Sail Pilot | Boat Autopilots | Raymarine
Evolution autopilot systems for mid-sized sailing boats with mechanical steering.
What's wrong with the wheel pilot? I've seen them work very well on boats up to 35'.
Is it calibrated?
Is the fluxgate compass located away from interference?
Is the drive belt and clutch in good condition?
Is the sail plan balanced? (ie: can you let go of the wheel and the heading stays true?)
The easiest alternative, from an installation point of view, would be using hydraulic AP drive. That would be a big expense and several days to install, along with a minor modification to the steering quadrant (tiller lever).
In my experience, the EV100 (with wheel pilot) is marginally better than the ST 4000 at course keeping (especially when in apparent wind mode) but it's not night and day.... maybe 10-20% improvement?
It might be worth spending a day inspecting and tuning the existing setup before dropping many BOAT units into a conversion?
Is it calibrated?
Is the fluxgate compass located away from interference?
Is the drive belt and clutch in good condition?
Is the sail plan balanced? (ie: can you let go of the wheel and the heading stays true?)
The easiest alternative, from an installation point of view, would be using hydraulic AP drive. That would be a big expense and several days to install, along with a minor modification to the steering quadrant (tiller lever).
In my experience, the EV100 (with wheel pilot) is marginally better than the ST 4000 at course keeping (especially when in apparent wind mode) but it's not night and day.... maybe 10-20% improvement?
It might be worth spending a day inspecting and tuning the existing setup before dropping many BOAT units into a conversion?
Last edited:
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 24,453
@marcham I like your suggestions. They are spot on.
I questioned the rationale for the query. Then I looked at his location. He is on the coast of Thailand. That suggests to me his sailing will be in the open ocean.
I have found the EV100 to be acceptable in seas of a meter as long as they are not following seas on my 35ft boat. When the conditions get spicy, the motor and wheel pilot hardware are not made for the stresses of such seaways.
I questioned the rationale for the query. Then I looked at his location. He is on the coast of Thailand. That suggests to me his sailing will be in the open ocean.
I have found the EV100 to be acceptable in seas of a meter as long as they are not following seas on my 35ft boat. When the conditions get spicy, the motor and wheel pilot hardware are not made for the stresses of such seaways.
I agree with you on this, and wish to add reason why the linear drive is highly preferred.
On all steering systems, there is a hysteresis' or “dead band” between the wheel and the rudder. What happens in rough conditions is that the boat needs continual corrections to compensate for the yaw which is introduced.
This continual correction factor is hard on the gearing, which are plastic gears.
By moving the actuation point directly onto the quadrant, you reduce the dead band, and the corrections are far less.
As well, the gearing in the linear drive is a cyclo cyclic planetary stack up, which is more robust.
I agree with the other comments regarding the necessity to calibrate well, etc. It is essential to ensure that the rudder reference mirrors the quadrant arm. This information is well documented in the installation documents