Yes the portholes were a major concern to the master ship designer Thomas Andrews so much that merely minutes after the crash this was one of the main concerns when it was determined Titanic was floundering so much that Andrews and a team of men set out to secure the portholes according to Charles Lightoller.
http://www.charlespellegrino.com/charles_lightoller.htm

"While Thomas Andrews and a small team toiled throughout the bow section, seeking out open portholes and closing them against the rising waters (for each porthole potentially opened an additional square foot to the ocean,..."

Dr. Charles Pellegrino's sight is full of interesting insights.

This with the testimony I found that the water tight doors were reopened and left opened actually help explain why the Titanic went down so fast.