Rather than trying to find the exact same light I suggest trying to find one that is compatible with your fittings. Do you have a photo of your current light and how it is mounted?
This is a good chance to upgrade to an LED-based light. They are very bright and much more efficient than incandescent-based ones.
I recently upgraded and used the Aquasignal 34:
aqua signal - Recreational boats - Navigation lights - Series 34 - LED navigation lights (Bicolor) - Article number 3863001000
My old (Hella) light was mounted to the bow pulpit, and it wasn't too hard to mount this one there.