Can the symptoms of PTSD cause amnesia?

The following excerpt from my book, Reconciliation, A Son’s Story demonstrates how a traumatic condition might wipe out a person’s memory of certain events.   

“It is very scary for me to find out over 40 years after the event that my 30 day cruise and experience aboard the USS Coucal (ASR-8) in 1965 had been completely blocked out of my mind for the most part.  I do remember bits and pieces like in a dream of being on the ship looking at the shore off Makaha Beach and the surfers feeling very sad about not being back on shore duty enjoying the benefits of surfing.  My experience aboard this ship was completely wiped out!  I can’t remember anything of any substance at all.  I am very anxious to find ways to remember this experience and what happened on board the ship for the 30 days out at sea.  I hope and pray my memory of this experience returns and helps me heal from what must have been a highly traumatic time in my life.  I had hoped that my Naval medical records from that time would reveal the experience, but there were no references of a medical condition or accident requiring treatment during my USS Coucal training cruise.”

Reference:
Following service in the Viet Nam War from September 1976 to September 1977, Coucal operated from her home port at Pearl Harbor, mainly supporting submarine training.  Coucal was decommissioned at Pearl Harbor.  In April 1990, ex-Coucal was sunk in the first PACFLT test of a Tomahawk anti-ship missile, fired from USS Chancellorsville (CG-62).  reference: http://en.wikipedia.org/wiki/USS_Coucal_(ASR-8)