That Bulge on a Ship's Bow Isn't for Ramming. It Makes a Wave on Purpose

That bulge under the bow of a big ship is not for ramming and not for ice. It is there to make a wave. In this video, drawn step by step: why a ship spends fuel on its own bow wave, how the bulb makes a second wave whose trough falls on the crest of the first, how the idea came by accident from 19th-century ram bows towed in test tanks, why a bulb only works near one speed and one draught, and why Maersk Line cut the bulbs off a class of its container ships and fitted new ones when the ships slowed down (a 200-tonne nose, built in China and shipped in five pieces; about 8% of the fuel, by Maersk's figure). All drawings are schematic: wave heights are exaggerated so that they can be seen, and the tank-test bars show the direction of the result only. Watch next: How the Biggest Oil Tanker Ever Built Stopped (It Took 9 km). If this was worth your time, a like and a subscription help the channel. And tell us in the comments: which part of a ship should we take apart next? Chapters 0:00 Not for ramming 0:52 The plan 1:06 1. The wave a ship makes 2:03 2. The wave that cancels it 3:13 3. Where the idea came from 4:33 4. The day it stopped working 6:27 So what is that bulge 6:41 Three takeaways Sources IMarEST, Ram bow revival that became the bulb: https://www.imarest.org/resource/ram-... University of Houston, The Engines of Our Ingenuity, No. 2715: Bulbous Bows: https://engines.egr.uh.edu/episode/2715 Ship & Bunker, Maersk Line Adjusts Bows for Slow Steaming (11 February 2013): https://shipandbunker.com/news/world/... Officer of the Watch, Maersk Ships Get New Bulbous Bow (12 March 2013): https://officerofthewatch.com/2013/03... All animations are original; diagrams are simplified and not to scale.