Here is a tip...
On my CP16 I have a cleat on each side at the stern to which I attach a line that I wrap twice around the tiller ( not snug) and then to the cleat on the other side. When I need to let go of the helm, I just pull this line towards the Bow or forward which then snugs it up and will hold the boat on course while I do whatever I need to do. When I ready to resume the Helm Just slide the Line back so that it is again loose. :wink:
I use a similar set up but with a pice of 1/4 inch shock cord. Set with the proper strtch tension, I can easily move the tiller and it will stay where I put it.
http://www.com-pacowners.com/4images/details.php?image_id=301
:)