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From: Martin Brown <'''newspam'''@nonad.co.uk>
Newsgroups: sci.electronics.design
Subject: Re: Full video of ship hitting and destroying the Francis Scott Key
 bridge in Baltimore
Date: Fri, 29 Mar 2024 11:18:04 +0000
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On 29/03/2024 06:06, UFO wrote:
> 
> Out of all the hours it sailed in operation, maintenance checks were all 
> fine
> then out of the blue not 1 but 3 power failures, and not out in the 
> middle of the ocean
> from harms way...just close enough to a bridge and hit the weakest spot. 
> What a
> "fluke"

Hardly. Murphy's law can apply IRL. Dirty fuel seems quite plausible.

The bridge was *designed* to fail catastrophically if anything hit one 
of its main supports which is unforgivable on a bridge that is over a 
waterway leading to one of the busiest Atlantic ports in America.

Most big bridges in first world countries have buffer islands and 
underwater structures to deflect and/or slow a large vessel to prevent 
them from impacting any of the key support structures near a live 
shipping channel. The ship may ground and be damaged and the bridge 
shaken by that impact but that should be about the limit of what can 
happen to a properly designed bridge in these circumstances.

>> I read that cargo ships of this size run diesel generators to power 
>> the steering pumps at low speed and then do PTO from the main shaft 
>> once they're cruising, and that the black smoke may have been an 
>> emergency generator coming up. But the steering pumps probably aren't 
>> a priority, in a river current that thing's a cork on backup power. 

Also it can take a very long time to alter course with a large vessel.

The ship issued a Mayday which saved lives by closing the bridge to new 
traffic before the impact but it was very sad for the road crews working 
on the road deck.

-- 
Martin Brown