There should not be much tension from the steering lines on the rudder pin. Also the rudder up/down lines are on bungy cords so they should not be left under tension (or they stretch out and become useless).
I have noticed on my TI that depending on the temperature of the hull, the entire boat grows and shrinks an alarming length. I know if I adjust the steering cables when the boat is very warm (like in the sun), once the boat cools down (like in the garage at night, or in the water) the cables are then very loose. As an Engineer I can explain.
(boring technical part)
The cooeficient of expansion for polyethelene is .000111" per degree per inch.
If the temp rises 75 degrees (example from 50f to 125f.... extreme example of sitting in the sun in your yard (summer), and sitting in your garage in november).
75 times .000111" = .008325" per inch expansion using a 75 deg rise.
18.5 ft x 12 = 222 (how many inches long the boat is)
.008325" x 222 = 1.848" ( the entire boat grows in length almost 2 inches when the temp of the hull rises 75 degrees).
What this means is if the steering lines we adjusted in the summer on a hot day, and you take the boat out into lake michigan, there will be 1 inch of slop in the control lines, that needs to be adjusted.
The cooeffieciency of expansion rate on the Ultra high density polyethene (spectra) lines is only 60 ( roughly half that of the PE hull), ie... half the length of the boat (length of control lines) times 2 (2 lines) works out to around 1 inch of play (roughly) with a 75 degree rise.
(end of boring technical part)
I usually end up adjusting my steering control lines every few weeks.
In my opinion there should be little to no tension (or very little) on the steering control cables. If they are very tight, and you adjusted the control lines in the cool, then put the boat in the sun, you could break the rudder pin, or control lines (one of those insermountable forces just like ice freezing).
You don't have to believe me, just measure the length of your boat with a tape measure in the garage, then sit it in the sun for a few minutes, it will grow over an inch and a half. So in the summer my boat is 18.8 iches, and in the winter it's 18.6 inches (lol).
The whole reason I found this expansion thing out is I have a solid aluminum bow sprit that mounts to the bow and is bolted to the front AKA braces (about 7 ft long) (which I made during the winter), . It didn't line up (too short) when I tried to mount it on a warm day in the summer (measured it three times and it was still too short LOL).
Hope this helps you.
cooeficient expansion tables (http://www.engineeringtoolbox.com/linea ... -d_95.html