How Bulbous bow increases the efficiency of a ship and what are its major functions and advantages?

Bulbous bow reduces the Hull wave making resistance of a ship, which is the major residuary frictional resistance of a ship. It reduces the bow wave, due to the wave generated by the bulb itself, making the ship more efficient in terms of energy. Here Blue and Green lines shows the wave generated by the bulbous bow of the ship and stem of the ship respectively. The Red line shows the resultant wave, which is reduced in amplitude due to the interference of one on other. Thus the hull wave making resistance is reduced. So more efficient and lesser fuel oil consumption.

So the major functions and advantages of a bulbous bow ships are

• Reduces the bow wave, due to the wave generated by the bulb itself, making the ship more efficient in terms of energy
• Increases the ship’s waterline length, slightly increasing the ship speed, reducing the installed power requirements and so the fuel oil consumption
• Works as a robust “bumper" in the event of a collision
• Allows the installation of the bow thrusters at a foremost position, making it more efficient
• Allows a larger reserve of flotation 
• A larger ballast capacity of fore peak tank
• Extra protection for panting and pounding