What is the cheat for boat in gta san Andreas?

I'm afraid there is no cheat for San Andreas sorry

however, you can spawn a hovercraft (vortex) (triangle, triangle, square, circle, X, L1, L2, down, down).

another way to get out of the water without a long swim is to spawn a jet pack (left, right, L1, L2, R1, R2, up, down, left, right) and then spawn a vehicle. as the vehicle sinks you can climb on top and when you're a little ways out of the water the jet pack will appear.