There are plenty of sites around the web which will give you the origins and meanings of nautical slang. Mostly the wrong ones. Etymology is a science: you can't just make stuff up.
What's the scuttlebutt?
'Scuttlebutt' is rumor or gossip. In any community there will be places where people like to exchange the latest gossip. In the days of sail the communal water butt was favorite. One may well imagine sailors swapping yarns around the water butt. But where does 'scuttle' come into it? There are two nautical meanings of 'scuttle'. One means to make a hole in something, as for example a ship, to sink it. The other one means a hatch or opening in the side of a ship for ventilation. Neither one applies here.
In the context of both a hatch and 'scuttlebutt', the word comes from Latin - 'scutella' - a small dish or drinking bowl. A hatch is most commonly square, but a scuttle is most commonly round - dish or bowl shaped - as for instance the round covers for glass portholes. Another type of scuttle deriving its name also from Latin is the coal scuttle.
In the days of sail a water cask would be broached - meaning that it would be newly opened. A dipper on a rope or chain would be to hand. The dipper was originally a bowl - a scuttle. Sailors would pass the scuttle at the butt. This became contracted to 'pass the scuttlebutt'. Finally, 'scuttlebutt' came to mean the rumors and gossip that were passed around the water butt like a scuttle. And the broaching of a cask by an officer was the ideal time to broach a subject with him - to open a topic for the first time. Even better, one might get together with a friend ashore in the snug2 and broach a cask of something stronger.
Broaching a cask of rum is fun. Broaching a ship is about as much fun as running full tilt into a wall. 'Broaching to' is best avoided. If you let go the wheel and the ship swings across the waves so as to slam sideways on into a wall of water - well - that's no time to broach the subject of a helmsman's low wages.
Of brass monkeys and cold weather
The best suggestion I have seen on the web for the origin of the phrase "cold enough to freeze the balls off a brass monkey" comes from Gary Martin1. He concludes that the original brass monkey was a naval cannon, and I concur. I would like to add a little more to his conclusions. The culverin drake, or 'munkey' had a tapered bore. Culverins were often mounted on a swivel on a rail. When not in use they would point downwards. One may easily imagine an arctic voyage where a brass shot in an iron cannon shrinks trivially in diameter, but enough to fall out of the barrel.
 - http://www.phrases.org.uk/meanings/...
 - the part of a bar, tavern or inn with comfortable chairs, and a fire in winter.