what about a couple of head lamps would that suffice?
Neil, a single headlamp is all you need to be legal. There is a popular school of thought that you are much better off also having a riding light - a lot of the guys won't go out at night without one.
I've been out quite a few times at night on middle harbour with just the headlamp. There is so little traffic and it is so quiet that I haven't had cause for concern. I do tend to have the light on all the time when in the main waterway. However, it only takes one drunken hoon to change all that.
Indeed, there is a local eccentric where I live who is seen power walking around the neighbourhood every day, covering substantial distances. He has only one eye. I learned his story. He was one of those drunken hoons who crashed his boat one night in Middle Harbour! I think a couple were killed and he was maimed. He can't work any more. Lost his marriage too (there's more to this than I'm passing on).
There is a possibility that even a riding light wouldn't help in case someone is hooning around at night like that. However it has to give you a better chance than no light.