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What it doesn't have is a bulbous bow which at a critical cruising speed sets up a counter bow wave to reduce hull drag. So the X-Bow probably isn't efficient f
by CalChris 4y ago
What it doesn't have is a bulbous bow which at a critical cruising speed sets up a counter bow wave to reduce hull drag. So the X-Bow probably isn't efficient for ocean transiting tankers and container ships.
- nabla9 4y agoBulbous bow is important in high cruising speeds speeds Drag ~ flow velocity squared. The new trend in cargo shipping is energy saving with slower cruising speed. Slightly slower speed and thinner ships don't need bulbous bow.
- CalChris 4y agoYou're talking about Slow Steaming but these ships still use a bulbous bow. Indeed older ships are actually being taken into dry dock and re-nosed to tune the cruising speed down to a slower more efficient speed. What happened was that a container ship could cruise across the Pacific at say 28 knots which is fast. But no one was paying for that speed which in fact used more fuel. On the other hand, a slower boat (Slow Steaming) used less fuel. It was more efficient and less polluting. https://www.marineinsight.com/wp-content/uploads/2013/01/The-guide-to-slow-steaming-on-ships.pdf https://www.marineinsight.com/wp-content/uploads/2013/01/The...
- nabla9 4y agoNose job often means complete removal of the bulbous bow. At slow speeds the wave resistance is smaller relative to frictional resistance, the bulbous bow increase hull wetted surface area and increases frictional resistance. It's function of to Froude number and block coefficient.
- CalChris 4y agoNo, they aren't simply removing them. They are replacing them with new ones tuned for a slower more efficient speed. http://www.oldsaltblog.com/2013/03/container-ship-nose-jobs-maersk-retrofits-bulbous-bows-for-slow-steaming/ http://www.oldsaltblog.com/2013/03/container-ship-nose-jobs-...
- pseingatl 4y agoEven with daily operating costs at ~25k or more?