it's not entirely the dealer's fault. spectra line will stretch when it's new.
i installed brand new line in mine and used 7/64" dynasteel because it was available locally. i have tightened it twice, maybe three times so far. other issues i have noticed:
Looks like the line sizes are:
1.75mm Spectra for my rudder lines on my Adventure.
2.2mm Spectra for my rudder lines on my TI.
After inspecting my rudder lines this weekend, I didn't find any signs of damage. Even were there were knots to accommodate the new rudder. Will keep a small spool of the stuff in my ditch bag just in case.
Wow, no wear at all? After 3 months use mine looked like they were attacked by an anger spouse with 12 grit sand paper. That, combined with all the knots, pushed me to fully replace the rudder lines. I made a very significant safety improvement when I did it. Hobie has three individual sections of rudder line and if one loop falls off a tiller post, the whole system fails. This happened to me and natural not on a nice day. The loops in my rudder lines for the tiller posts are looped though each other and crimped in place. So it is one complete line rather than three separate pieces. see pic...
I also added a closed eyelet, the OEM hook rotated on me once, the rudder lines fell off, and I lost steering.
I've been having issues with my rudder off and on since getting my boat six months ago.
As I've dissected the rudder system and the control lines in greater and greater detail, I've found that the knots used on the control lines are not appropriate and in general not safe for long term use.
The most widely used knot is the overhand knot http://en.wikipedia.org/wiki/Overhand_knot
. The key problem with the overhand knot is it's strength. It causes a 50% reduction in line strength due uneven wearing and stretching. Over time, this will increase until the line FAILS.
Much better would be the figure eight knot http://en.wikipedia.org/wiki/Figure-eight_knot_%28ropes%29
. It causes a 20% reduction in line strength.
The blood knot which is ideal for slippery line like spectra or monofilament line and causes a 20% reduction in line strength.
The bowline, double bowline, double fisherman's knot, carrick bend, sheetbend, and double sheetbend could also be considered.
I found that overhand knots were used in the running length of a line merely to shorten the line. This is something that a knot should NEVER be used for because it weakens the line. If it has to be done, at least use a knot appropriate for the use and that does the least damage.
I think that with all the sailing experience Hobie has they would know better.
I have ordered new spectra cord and will be replacing all of the existing rudder line. I think I will also install a turnbuckle in the system to tension the lines
sorry for the long post but i thought some of it was relavent