# Could any bridge have withstood Baltimore collision? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [March 29, 2024, 1:20am UTC](https://boards.straightdope.com/t/could-any-bridge-have-withstood-baltimore-collision/999539 "2024-03-29T01:20:24Z")\ **Posts on this page:** 1\ **Showing post:** 27
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 1, 2024, 2:43pm UTC](https://boards.straightdope.com/t/could-any-bridge-have-withstood-baltimore-collision/999539/27 "2024-04-01T14:43:19Z")
> [@Whack-a-Mole](#): > > ETA: Thinking more, I do not know if a tug could manage to push a ship with its bow or get a tow line hooked up and do something while such a big cargo ship is going 8 knots. Seems dangerous too. **[According to Wikipedia](https://en.wikipedia.org/wiki/Tugboat#:~:text=A%20tugboat%20is,above%20%22normal%22%20tugboats)**, the largest commercial harbor tugs out there are capable of a bollard pull of 60-65 tons. The Dali weighs in at around 100,000 tons. If the Dali is moving forward at 8 knots, I don’t think you can effectively point the tug perpendicular to it, because then your tug would be moving sideways at 8 knots. I suspect you’d have to keep the tug pointed at least somewhat in the same direction as the Dali is moving, which would mean it can’t exert all of its 60 tons of force perpendicular to the Dali’s path of travel. Even if I’m dead wrong, the most a tug could manage is to push sideways on the bow/stern of a 100,000-ton boat with ~60 tons of force. We’re not trying to shove the entire boat sideways, just rotate it a bit - but even so, it’d take maybe 30 seconds to give the bow or stern a lateral velocity of just 1 knot, and that’s assuming your tug is already optimally positioned to do the required pushing the moment an emergency arises. And as @LSLGuy points out, it’ll take more time than that for the ship to stop skidding and actually start traveling in the direction the bow is now pointed. Then there’s the cost. **[As was pointed out in the other thread](https://boards.straightdope.com/t/bridge-collapse-in-baltimore-2024-03-26/999372/210)**, the charge for an hour of service from a tugboat in Baltimore Harbor is $3100, with a minimum two-hour charge, and you’d need at least two tugs. So you would add $12,400 to your cost of arrival, and another $12,400 to your cost of departure. For every ship. > [@LSLGuy](#): > > Ultimately, the way to reduce these monster forces is to move the ships at nearly zero speed. Cruise ships with multiple azipod props at the stern and multiple large transverse (or azipod) thrusters at the bow can maneuver with great control and poise at fractions of a knot. It’s about 5 miles from the Port to the Key bridge. Last week, Dali covered the distance in about 50 minutes; if speed is restricted to 1 MPH, the same trip will take five hours, i.e. an extra ~four hours. Assume the same thing happens whenever it reaches its destination port - so instead of a 10-day journey (240 hours), it’s more like 248 hours, about four percent longer. The crew costs for those extra eight hours don’t amount to much, but now every ship is moving about four percent less cargo per year than it used to. We will need four percent more ships to move all the goods we’re currently moving. --- _[View the full topic](https://boards.straightdope.com/t/could-any-bridge-have-withstood-baltimore-collision/999539)._