Servo's

 

You're probably going to need at least one of these things (either for steering, or for bait release or hook release).

 

They're pretty simple pieces of kit.  Basically a small motor will move an arm back and forward (controlled by one of the sticks on your transmitter).  The arm doesn't spin all the way around but moves between 60 and 90 degrees (depending on the model) and returns to the center position when your control stick is centered.  They're fairly cheap and easy to get hold of.

 

Note:  All servo's are rated in terms of the force that they can apply when pushing or pulling.  Be aware of this when choosing the right one for you.

 

Other Useful Items  -  Retracts!

 

Whilst trying to work out a decent bait release system I came across some things called 'Electronic Retracts'.  These great little items are used to raise and lower landing gear on model planes but they are in my opinion perfect for incorporating into a bait release mechanism.  More details on this in the Bait Release section and also in my latest build details.  They're fairly cheap (2 for less than £10) and work like a dream.  Get them from here or of course Ebay.  Pic on the left and also a You Tube vid here in case you want to see how they work.