Where does the phrase "do you catch my drift?" come from?

With all the speculation here I figured it was worth looking into the origin of 'catch my drift' and its usage. Then it made simple sense...
Ok, you are the pilot on a sailing ship before electronic navigation. The pilot is steering a course in relatively calm waters and ties the steering wheel in place with a short length of rope and walks to the rail to smoke his pipe. He leaves a deckhand near the wheel to watch the direction of the ship relative to the night sky.
When the ship begins to drift off course, the deck hand 'catches his drift' and notifies the pilot - who immediately sets in a new course to compensate for the drift of the ship.
The key here is that 'drift' is not a mistake to the captian, it refers to 'real direction'. In heavy winds he might be pointed many degrees off course but the boat is actually moving (drifting) exactly where he wants it to go. So 'drift' means the actual direction of the ship's movement rather than the direction where the ship is pointing.

... Well, back to the present.. a speaker has a point he wants to make, the 'drift' of his speech/talk. The points he makes may use exmples from all kinds of seeming unrelated things but help establish the direction (drift) of his speech. A person who really understands what the speaker is trying to say really does "catch his drift" regardless of the wanderings of the exmples and points he makes along the way.

When someone says, "do you catch my drift?" they are not accusing you of being dense. They are actually saying "I know I probably used confusing examples and wierd ways of explaining myself, but underneath all of that was a main concept I was trying to get across. Do you understand what I was trying to say about that concept?" ...

So isn't 'do you catch my drift', a much easier way of saying all of that.. I think so. Now that I understand the main point of it, I am sure I will.. :)