I hate to be the bearer of bad news, but you will probably have to remove the Brightsides and primer, then coat with an appropriate paint if you will be leaving the boat in the water that long.  The following is pasted from the Brightsides page on this site:

   "The instructions on the can say "Not for use below waterline," which causes some confusion.  What Interlux means by this is that it isn't for big, heavy boats that live in the water for months or years.  For kayaks, canoes, dinghies, rowing boats and so on, which never spend more than a few weeks at a time in the water, Interlux Brightsides is perfect and we've been using it on small boats for 25 years. If your boat is going to live in the water for days or weeks, you should consider using either a two-part linear polyurethane paint or an herbicidal bottom paint. Don't use primer beneath Brightsides in areas that are fully immersed."

No doubt that you could cover the Brightsides with a barrier coat but I am not convinced that is a good solution.  Any nick or ding in the top layer will expose the Brightsides layer to water, and the paint will start coming off over time.  

I strongly suggest that you call Interlux Tech Support to get the best advice. 

  I agree.   Remove the Brightside paint from the below the waterline, and the waterline.  My in the water boats all had the bottom paint  on primer and/or the hull.