Expiriing License

Hey all. I have a USCG unlimited 3rd Mates expiring September 2015. a few years behind the desk and I got the itch to sail. If I start sailing after the new year (lets say like feb/March 2015) can i keep my license valid? Is there an extension to the 1yr of sea time in 5 years rule as I wont have a full year of time before it expires. I know i need to get a new security endorsement thats newer since ive been licensed, thats no problem. Anyone have any advice on this. Can I sail?