Got a question for those of you that are familiar with using the Ultrex I got another boat and it came with an Ultrex 112 when I picked up boat the guy went over the Ultrex and it's buttons, he told me that when I used Spot lock or Auto Pilot I had to push the constant button then push the Spot Lock or Auto Pilot button which I did this weekend and both worked fine but I did realize that I did not have to push the Constant Button to use the spot lock , I was watching a Video on Ultrex operation and he was showing how to point the TM head at where you want to go and then hit constant button and not the Auto Pilot button. I looked at the manual and it said that the Auto Pilot was used with the I Pilot Hand Held and never said anything about using the I pilot button for a steady heading so I'm confused on what the Auto Pilot button is used for if the Constant button is used for locking onto a target and heading in a straight course till you mask pedal.

The Spot Lock is it's own button as you discovered. No need to press anything else or change the speed.
The Constant button is just like it sounds it just makes the TM go at the speed and direction you decide. You can steer while running in constant.
The Auto Pilot I believe is used in conjunction with a Humminbird Depth finder and will follow a trail you have previously setup. I have Lowrance Units so have no Idea about how this works.
The IPilot is the remote control I have used this a few times and it functions just like I was up there steering and deciding the speed of the boat.
I hope this helps and I am no expert for sure, I might have given you some incorrect info but this is what I have found.

Jody

Spot Lock is one button.

Constant only means the motor is running constantly at whatever speed you have it set at. Just like on a trolling motor with out iPilot.

The Auto Pilot button sets the TM to a specific heading and the TM will do it's best to maintain that heading adjusting for current and wind. It does not require the TM to be connected to a graph. It is the iPilot link functions like go to a waypoint and follow the contour that require the connection to a Humminbird.

I run a Terrova and most of the time the motor is set to constant with the auto-pilot on. I use the foot pedal to make small directional adjustments and wear a micro-remote to adjust speed, and direction if I have stepped away from the foot pedal. You do have to develop a certain level of trust in the auto-pilot, but once you do it really makes boat control so much easier.