After reaching the canals, you'll find a hovercraft. Alyx will give you some brief instructions on how to operate it. The hovercraft is fast and can absorb some damage, but it's not invincible. Your primary weapon on the hovercraft is a mounted pulse rifle. Use it to destroy Combine barricades, explosive barrels, and any enemies you encounter. The canals are linear, but there are often side paths that lead to supplies or alternative routes. Keep an eye out for these.
Half-Life 2
Hovercraft Introduction
Master the hovercraft in Half-Life 2. Utilize its pulse rifle to destroy barricades and enemies while navigating the canals and seeking out hidden supplies.