Naval question: what’s a weather column?

I have just been reading about naval battles to try and get a bit better at them and a weather column was mentioned in the Battle of Trafalgar and Cape St Vincent so I was just wondering what it was and why you would have one.

Also is raking fire and crossing the T the same thing.

In the Age of Sail the position regarding to the direction from where the wind blows was very important.

Lets say we have too lines of ships stretched out from west to east and wind blowing from the north.

The northern line would be the weather column (upwind) and the southern line the leeward column (downwind).

Being windward was mostly advantageous, as you had maneuver advantage. You basically had the "wind in the back" if you decided to move closer to your enemy, those in Lee on the other side had to cruise against the wind to reach you.

But the leeward position also had some advantage. In heavy winds the upwind position might not be able to open its lowest gunports, as the wind pressed the ship leewards and might do so strong enough to prohibit a ship from opening its lowest gunports.

Its related:

Crossing the T is a Maneuver performed by a battle line to allow raking fire.

Raking fire is generally firing through the bow or stern of an enemy ship.

So crossing the T is the means to achive Raking fire, but 2 individual ships could rake each other also in a normal engagement and that wouldnt be called crossing the T.

Weather column in this instance is the column that has the weather gage or in other words is upwind from the other.

Raking fire is not the same as crossing the T. Crossing the T is a manoeuvre carried out in order to get in a position to give raking fire. And during the approach, one must suffer raking as well. Raking fire itself is the firing of cannons in such a fashion that the ball might travel the entire length of the ship.

Raking fire is the concept of firing along the longest axis of an enemy formation(ie from the side of an infantry line or through the bow/stern of a ship). The idea is that you have more things to pass through before your ammunition can hit nothing(and in the case of ships, the armour of ships tended to be much weaker in the bow/stern).

Crossing the T is a manoeuvre in ship line combat where your line passes in front of the enemy line and thus lets every one of your ships fire a broadside down the length of their line(think focus fire in normal RTS terms).

I'm not really sure what weather column refers to in regards to naval combat however so someone else will have to explain that.

Edit: Elmar beat me to it >.<