Just installed a NAVMAN 3380 (The new color version) on Lady Kay, a 1989 Catalina 42, and immediately put 1000 miles on it.
After comparing features and cost, it proved to be the best value. Internet prices are good....got mine at
http://www.wmjmarine.com/
The "brain" seems to be pretty smart. In addition to a plethora of information and ways to display it, it has a variety of steering parameters....ratio's and gains, that can be adjusted, and stored in up to five "profiles" for different sea states/points of sail. There is also a "rate gyro" that allows for "adaptive learning". It all seems to work. Of course following seas is the hardest nut to crack, and it did a resonable but not perfect job. Other than that, the wheel movement eventually reduces to the minimum required to keep the course within the parameters you specify. This is good, because the pump is not exactly a power miser....bursts of 15+A happen...depending on sea state and rudder activity consumption will range from 3-4 to 10-15 Ah.
The installation is straight forward, and instructions are clear. Rams come in 12/7", with either 880, or 1320 pounds of thrust. Here's where it gets tricky. Depending on the lenght of the tiller arm on your rudder shaft, and the throw of the ram, you will get certain rudder travel and torque.....
Example: As per NAVMAN a 12" ram, 38mm (880 pounds) on a 10" arm will steer a boat up to about 28000 pounds, (about 733 ftlbs of torque) and yield 30 degrees of rudder travel either side of center.......
I just went through all this. Lady Kay has 45 degree of rudder travel, so I ended up mounting the ram on 7" arm......BUT the torque is then reduced to about 513 foot pounds of torque, and that proved insufficient. So I am replacing the 38mm ram with the 45 mm ram.
If you call NAVMAN tech support you get a helpful English speaking person in Massachussets after 1 menu choice, and just a few rings....
So, you need to know what your rudder travel is now, in degrees either side of center, and how heavy your boat is. Also, do you have a tiller arm already on the rudder post? How long is it? (center of hole to center of rudder post) Are there provisions for making holes at different distances? Tiller arms are NOT included with the autopilot. I got mine from Edson....10" for a 2.8" shaft around $350....
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