Ok, I'm new to photography and I love it, I think I'm doing ok on daylight pictures, but I have no idea what kinda settings to use for a low light situation like inside of a submarine, any help will be appreciated.
Welcome to the Nikonians and thanks for posting your question. Low light photography can be approached in many different ways depending upon the subject you want to capture and the surrounding environment.
You should consider getting some books, DVDs or similar on exposure to better understand the challenges of low light photography.
A good read is Bryan Peterson's "Understanding Exposure" There is a whole chapter about low light photography. It's available on Amazon and several of the camera web sites.
"Red is gray and yellow white, but we decide which is right ....and which is an illusion"
adribyers, I'll second luckyphotos endorsement of Bryan Petersons book, 'Understanding Exposure'. I struggled to understand manual settings and their relationship with each other I'm only around one third of the way through that book (about $8 on Amazon Kindle, can read it anytime on my phone or tablet) but I now prefer manual setting so I can control most of the pic. Definately the best book I've read so far on photography, will help you understand low light photography.
A good support system is needed to keep the camera still during the longer shutter speeds. While a tripod may not be allowed, you can try leaning against walls and bulkheads.
Increasing the ISO will allow for shorter shutter speeds since the camera will need less light. However digital noise will become apparent in the shadows.
A wide aperture (small f number) will shorten the shutter speed but also narrow the depth of field of items in focus. A small aperture (big f number) will give you more items in focus but require a longer shutter speed.
---------+---------+---------+---------+ Joseph K Seattle, WA, USA
And of course there is your flash. With the confined spaces inside a submarine, you should be able to get some very interesting effects by using your SB 600 off camera and controlling it remotely with your onboard flash in commander mode.
Don't know whether you subscribe to Lynda.com - but just in case you do, Ben Long has quite a good 4 hour course on Low Light Photography (and Exposure too for that matter). No experience in Submarines though!
When words become unclear, I shall focus with photographs. When images become inadequate, I shall be content with silence. - Ansel Adams