Hobie Rudder Help

[dorf]

I have a 2007 Hobie Outback.
Saturday I was out in the harbour. As I was pedaling along I would start to turn left. I would try to move the rudder to the right to keep on course but there was no changing it. I went in a tight left circle. I looked back to see if there was anything caught in the rudder and it was clean. It looked as though the rudder was starting to lift on its own. I lifted the rudder and put it back down. A short time later this happened again. This happened about 6 times in the space of 15 minutes. It was very frustrating. When I got home I took a closer look. I couldn’t see any obvious signs of damage and it appeared to work fine.

I was wondering if anyone else was having a similar problem and if there was any easy fix for this (screw or lines to tighten?).
Any help would be greatly appreciated.

Thanks.
Paul.