yes...no...maybe?
Need a little more info. What background, experience, qualifications, timeframe? What the employer is really going to care about, above all else, is what did you do with the time/opportunities presented while on shore duty, and what can you add to their organization. All things being equal, as long as you make good use of your time (i.e. complete a degree...not mandatory just a suggestion) then it can help you. If you simply coast for the next three years and have nothing to show for your time, then it will hurt you.
Just my opinion
-Matt