Hello Paul ...
There is no need to tie a line around the CB from port to stbd. With the Mast out, you will see that there is a pipe coming up from the bilge and cabin sole, and into the mast from below. This pipe houses the CB pennant. All you need to do is to make sure the Board is all the way up, and then simply tie a figure 8 knot in the Pennant at the top of the pipe, and then the Board, and pennant cannot not go down at all.
You need to make sure you attach a messenger line to your CB pennant when you pull your mast ... this messenger will then stay with the mast, and will pull the Pennant back through the mast when you step it again in the spring.
Give me a call at (208) 788-0025 and I can explain the process and the configuration and send you pictures if you'd like. I have Hull #26 so we are probably identical.
Congratulations on your new purchase !
Cheers, John Marsh