(1) The action points of gravity and buoyancy are all on the submarine, so the action points should be drawn on the submarine; Gravity is vertical downward and buoyancy is vertical upward; Buoyancy should be greater than gravity.

The answer is as follows:

(2) Xiaohong's connection mode: "220V 60W" and "220V 15W" are connected in series, and the currents passing through the two bulbs are equal. The resistance of .60W bulb is less than that of 15W bulb; According to P=I2R, the actual power of 15W bulb is greater, that is, 15W bulb is brighter.

So the answer is: