Francis Scott Key Bridge (I-695) complete collapse after large ship hits it

[kphoger]

PS, if anyone could give me some tips on how to upload photos to Flickr and then format it so the photo post directly on my post that would be helpful.

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[url=https://flic.kr/p/2qYLHpf][img]https://live.staticflickr.com/65535/54463702952_35e365e7c3_b.jpg[/img][/url][url=https://flic.kr/p/2qYLHpf]Key Bridge with Islands to protect the pylons[/url] by [url=https://www.flickr.com/photos/158840276@N03/]plutonicpanda[/url], on Flickr
Key Bridge with Islands to protect the pylons by plutonicpanda, on Flickr

[PColumbus73]

PS, if anyone could give me some tips on how to upload photos to Flickr and then format it so the photo post directly on my post that would be helpful.

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[url=https://flic.kr/p/2qYLHpf][img]https://live.staticflickr.com/65535/54463702952_35e365e7c3_b.jpg[/img][/url][url=https://flic.kr/p/2qYLHpf]Key Bridge with Islands to protect the pylons[/url] by [url=https://www.flickr.com/photos/158840276@N03/]plutonicpanda[/url], on Flickr
Key Bridge with Islands to protect the pylons by plutonicpanda, on Flickr

Add MUTCD compliant warning signs for the bridge so ships can see it and avoid the islands and towers.

[Beltway]

How's this for a bridge protected by dolphins?
https://www.pinterest.com/pin/420031102731086540/

Flipper will protect your divers from underwater threats -- but while he likes to jump briefly out of the water and likes the sensation of being in the air, his domain 99% of the time is underwater -- so he can't protect you from surface threats.

How dare they post a conceptual image of the bridge design instead of full construction plans.

Highway design teams don't have full construction plans at the preliminary design phase.

The real issue: MDTA's PR blunder in showing a cable-stayed bridge without the promised ship-collision protection system. Fenders or dolphins should've been in the concept to reassure the public post-Dali. It's not about final plans -- engineers are still studying -- but leaving out safety visuals is tone-deaf. This isn't a scam, just a dumb oversight. Hari-kari, stupidcide, stupid-kari, dumbcide . .

Add MUTCD compliant warning signs for the bridge so ships can see it and avoid the islands and towers.

The Manual on Uniform Traffic Control Devices (MUTCD) governs road traffic signs, signals, and markings, not maritime navigation.

Ship guidance falls under the U.S. Coast Guard's Aids to Navigation (ATON) system, using buoys, lights, and dayboards compliant with IALA standards.

In fog or other inclement weather, there are a variety of radar, radio and GPS systems utilized by mariners.

[Max Rockatansky]

Outside of this forum and other like dark holes of this fandom I doubt there is much critique to be found regarding road concept art. 

[PColumbus73]

The real issue: MDTA's PR blunder in showing a cable-stayed bridge without the promised ship-collision protection system. Fenders or dolphins should've been in the concept to reassure the public post-Dali. It's not about final plans -- engineers are still studying -- but leaving out safety visuals is tone-deaf. This isn't a scam, just a dumb oversight. Hari-kari, stupidcide, stupid-kari, dumbcide . .

Clutch those pearls.

Add MUTCD compliant warning signs for the bridge so ships can see it and avoid the islands and towers.

The Manual on Uniform Traffic Control Devices (MUTCD) governs road traffic signs, signals, and markings, not maritime navigation.

Ship guidance falls under the U.S. Coast Guard's Aids to Navigation (ATON) system, using buoys, lights, and dayboards compliant with IALA standards.

In fog or other inclement weather, there are a variety of radar, radio and GPS systems utilized by mariners.

[Beltway]

There are certainly opportunities for expanding the navigational envelope with a cable-stayed bridge.  I wouldn't necessarily rule out a vertical clearance of 200 ft or more for ships, since the Bay Bridge may well be replaced at some point.

The new Key Bridge will need to span approximately 5200 ft of water.  Per Wikipedia's list of longest cable-stayed bridges, the current record-holder for main span length is the Russky Bridge near Vladivostok at 1104 m (3622 ft).

One engineering question that needs to be answered is the depth of water at which a vessel with the tonnage of the Dali can be expected to run aground instead of carving its own channel, possibly inflicting structural damage on a pier before it stops.

According to the latest nautical chart from NOAA, Baltimore Harbor has a navigational channel with a nominal depth of 50 ft that runs essentially from one main pier of the Key Bridge to the other.  If a hypothetical cable-stayed replacement had a main span of 3600 ft centered on that of the former bridge, the ends would be in water 23 ft deep at the north and 19 ft at the south.  I don't know if this would afford sufficient margin to intercept an errant container ship.  Given that the Chesapeake Bay has a deep muddy floor, it may also be an awkward location for pushing the envelope in terms of span length.  It may well be more cost-effective to trade space between the main piers for enhanced protection with structural dolphins, artificial islands, and so on.

As it happens, the Sunshine Skyway has a main span length of about 1200 ft--approximately the same as the old Key Bridge--but, as it is now over 35 years old, its defenses may not offer all that much protection from today's container ships.  The Mullet Point navigational channel, which runs underneath the main span, also has a nominal depth of only 43 ft.

The original bridge had span length of 800 feet which some shipping concerns at that time said was too short.

Now the same thing is being said about 1,200 feet given the massive increase in ship sizes in the last 30 years.

Skyway vertical navigational clearance (VNC) of 185 feet is now at least 30 feet lower than what the most recent shipping channel bridges have been providing.

It has the same 185 feet of VNC and 1,200 feet of HNC as the Key Bridge did.

The Skyway is one of the bridges that some maritime interests have declared inadequate for current and future shipping clearances, and they are calling for replacements. Functionally obsolete after only 30 years.

Water depths are 22 feet or more at mean low water for 2.2 miles along the Skyway route. Some heavy ships can still operate there without running aground. With spring tides and northeasterly high winds the waters can be 5 feet deeper.

The official nautical chart online --
NOAA Chart 11412 Tampa Bay and St. Joseph Sound

Water depths at the Sunshine Skyway main piers is 30 feet MLLW.

Given high tides and Spring tides and strong westerly winds it could be 35 or 36 feet which is almost the draft of the Dali, and some very large ships would still draw less than that.

I was rereading a book on the Sunshine Skyway disaster and it said that MV Summit Venture was lightly loaded ("in ballast") and was drawing 21 feet at the bow and 32 feet at the stern. A differential typical for a lightly loaded bulk carrier.

So that is another factor to allow for in a protection scheme. The forward part of a 600 foot long ship could be a lot higher in the water than the stern and drawing a lot less water than the average for that ship. In other words, partly or wholly defeat a protection scheme based on water depth.


I worked up a report on this event, highlighting the similarities and differences with the Key Bridge.

The chief difference was that the Baltimore incident happened in clear weather and in a channel that was tangent (straight) from Fort McHenry all the way to 2 miles east of the bridge. So especially for an eastbound (outbound) ship like Dali there are no channel bends even remotely near the bridge.

The Sunshine Skyway disaster was a perfect storm of multiple factors to the point that the handling of the vessel cannot really be blamed, nor the design of the bridge. Although these were very controversial at the time in the aftermath.

The Sunshine Skyway disaster occurred on May 9, 1980, when the freighter Summit Venture collided with the Sunshine Skyway Bridge in Tampa Bay, Florida, causing a portion of the bridge to collapse. Here are the key facts and findings.

Weather Conditions
- The collision happened during a severe thunderstorm with winds gusting up to 70 mph and zero visibility.
- Heavy rain and squall lines made navigation extremely challenging, obscuring buoys and other visual aids.
- There was an about 90-degree change in wind direction (from SW to NW) during the severe thunderstorm, which made navigation unpredictable and extremely difficult.
- The ship's radar was rendered nearly useless in the dense rain, which obscured both the channel markers and nearby hazards. No GPS tracking systems back then.

Channel Design
- The shipping channel under the Sunshine Skyway Bridge was narrow and lacked modern navigational aids.
- The bridge's piers were not adequately protected, leaving them vulnerable to collisions.
- The channel included a 18-degree dogleg turn just a quarter-mile west of the bridge. This abrupt turn added to the challenge of navigating eastbound (inbound) large ships in poor weather. Local ship pilots called this the "Combat Zone" due to the risks in passing the bridge and oncoming vessels safely.
- After the disaster, the replacement bridge incorporated enhanced safety features, including rock islands and dolphins (barriers designed to protect bridge piers). [I have already opined on the impossibility of testing and verifying this thru real-world tests.]
- The replacement bridge had a main span 1,200 feet long -- compared to 800 feet on the original which some mariners considered marginal for large ships.
- The replacement bridge main span was built about 1,000 feet east of the original -- alleviating the closeness of the bridge to the channel 18-degree dogleg.
- The Tampa Bay deep shipping channel is dredged and takes a number of bends and doglegs between the Gulf and the terminals.

Impact and Aftermath
- The MV Summit Venture weighed about 19,000 tons and was moving at 8.5 knots (9.5 mph).
- The Summit Venture was reportedly blown out of the channel due to strong winds and low visibility, putting it dangerously close to the bridge's unprotected piers.
- All of this unfolded at the worst possible moment — right as the ship approached the bridge -- at 0.2 mile from the bridge visual and radar views were obscured by the torrential rain.
- The collision caused the collapse of the southbound span of the bridge, sending six cars, a truck, and a Greyhound bus plunging into the water.
- 35 people lost their lives, with only one survivor.
- The disaster led to the construction of a new Sunshine Skyway Bridge, which opened in 1987 with improved safety measures.

Investigation and Findings and Legacy
- The NTSB (National Transportation Safety Board) determined that poor weather forecasting played a role, as it did not provide adequate warnings about the severity of the storm.
- The ship's pilot, John Lerro, faced both a pilot association investigation and a court case. However, he was ultimately held blameless for the incident. The court recognized that he had followed appropriate procedures to the best of his ability under impossible circumstances. A perfect storm so to speak.
- John Lerro was unfairly castigated in the state and local press and by his Tampa Bay piloting colleagues. The press mainly out of ignorance of the technical issues at hand, which is par for the course for them, and his piloting colleagues due to the fact that they saw him as an affirmative action hire.
- John Lerro even after his exoneration, was still attacked by some in the press, some in the piloting association, and some in the court system. It was a dogs breakfast.
- This disaster highlighted flaws in bridge design, including the narrowness of the main span (800 feet), the closeness to the channel dogleg, and the lack of protection for the bridge piers.
- The new Sunshine Skyway Bridge built after the incident included dolphin structures to shield the piers, had a longer main span of 1,200 feet, and was relocated to a safer distance from a 18-degree dogleg in the shipping channel.
- The event also underscored the importance of advanced navigation aids and improved weather forecasting for maritime safety.

The Summit Venture freighter was moving at approximately 8.5 knots (about 9.5 mph) when it collided with the Sunshine Skyway Bridge. While this speed might seem relatively slow, the ship's massive size and weight of over 19,000 gross tons meant that even at low speeds, the impact force was substantial enough to cause the catastrophic collapse of the bridge's southbound span.
. . . . .

NTSB-MAR-81-3
National Transportation Safety Board
Marine Accident Report
Ramming of the Sunshine Skyway Bridge by the Liberian Bulk Carrier Summit Venture, Tampa Bay, Florida, May 9, 1980

Quote:
The National Transportation Safety Board determines that the probable cause of this accident was the SUMMIT VENTURE's unexpected encounter with severe weather involving high winds and heavy rain associated with a line of intense thunderstorms which overtook the vessel as it approached the Sunshine Skyway Bridge, the failure of the National Weather Service to issue a severe weather warning for mariners, and the failure of the pilot to abandon the transit when visual and radar navigational references for the channel and the bridge were lost in the heavy rain. Contributing to the loss of life and to the extensive damage was the lack of a structural pier protection system which could have absorbed some of the impact force or redirected the vessel. Contributing to the loss of life was the lack of a motorist warning system which could have warned the highway vehicle drivers of the danger ahead.
. . . . .

Separated out in bullet points --
The NTSB's probable cause for the Sunshine Skyway disaster identified several key factors:
- The Summit Venture unexpectedly encountered intense thunderstorms with high winds and heavy rain, which severely reduced visibility and made navigation extremely difficult.
- The National Weather Service failed to issue a severe weather warning for mariners, leaving the ship's crew unprepared for the sudden and extreme conditions.
- The pilot lost both visual and radar references for the channel and the bridge due to the heavy rain, which contributed to the ship veering off course.
- The pilot did not abandon the transit despite losing critical navigational references, which ultimately led to the collision.
[my opinion was that the loss of both visual and radar references occurred too late and too close to the bridge. He didn't want to veer sharply back into the channel because he knew that could cause a collision with a gasoline tanker coming the opposite direction, very close but invisible in the storm.]
- The absence of a pier protection system to absorb or redirect the impact contributed to the extensive damage to the bridge.
[my opinion on that has been posted before]
- The lack of a warning system for highway vehicles also contributed to the loss of life, as drivers were unaware of the danger ahead.

Is "probable cause" an indecisive term?

The NTSB uses "probable cause" because investigations often face incomplete evidence — wreckage may be lost, data corrupted, or witnesses unreliable. "Probable" acknowledges this uncertainty while asserting the most likely cause based on rigorous analysis. It's a precise term, avoiding absolute certainty when evidence isn't conclusive, ensuring credibility and legal defensibility.

The NTSB's "probable cause" is not indecisive because it reflects a rigorous, evidence-based conclusion drawn from extensive investigation, including data analysis, witness interviews, and expert input. It identifies the most likely reason for an accident, balancing precision with available evidence, and is explicitly distinguished from speculative or inconclusive findings.

The legal defensibility may be the most important -- NTSB reports are for determining accident causes for the issuance of safety recommendations to the industry and government -- not intended to be used in a court of law to settle any disputes about the accident.

Sources:
Skyway: The True Story of Tampa Bay's Signature Bridge and the Man Who Brought It Down, by Bill DeYoung, 2013.

The NTSB accident report for the Sunshine Skyway disaster is titled "Marine Accident Report: Ramming of the Sunshine Skyway Bridge by the Liberian Bulk Carrier Summit Venture, Tampa Bay, Florida, May 9, 1980" (NTSB-MAR-81-3)

[Max Rockatansky]

I'm starting to think this thread needs a Goat Quote or two.

[The Ghostbuster]

The animal or Greatest of All Time?

[Max Rockatansky]

The animal or Greatest of All Time?

The pyramid variety which pleases Goat Jesus but often has the side effect of locking threads.  I'm prepared to sacrifice this thread in the interest of making goats happy.

[jeffandnicole]

I skimmed a lot of what was said, but I did catch this...

The chief difference was that the Baltimore incident happened in clear weather and in a channel that was tangent (straight) from Fort McHenry all the way to 2 miles east of the bridge. So especially for an eastbound (outbound) ship like Dali there are no channel bends even remotely near the bridge.

Left out of this was the incident occurred at night, which is a very important detail.

Left out of this was the incident occurred as the ship lost, regained, and lost power again, which is a very important detail.

Weather may have been clear.  Darkness makes viewing objects and obstructions harder.  Electrical issues on the ship further impacted the ability to go straight.

[Beltway]

I skimmed a lot of what was said, but I did catch this...

The chief difference was that the Baltimore incident happened in clear weather and in a channel that was tangent (straight) from Fort McHenry all the way to 2 miles east of the bridge. So especially for an eastbound (outbound) ship like Dali there are no channel bends even remotely near the bridge.

Left out of this was the incident occurred at night, which is a very important detail.
Left out of this was the incident occurred as the ship lost, regained, and lost power again, which is a very important detail.
Weather may have been clear.  Darkness makes viewing objects and obstructions harder.  Electrical issues on the ship further impacted the ability to go straight.

I didn't go deep into what happened in Baltimore in that post. My quote sums up that it was gross and criminal negligence that a cargo ship was operated that way in confined waters.

I don't know whether the weather was clear in the sense of a cloudless sky. But ..

The camera that captured the collapse was mounted on a home in Riviera Beach, Maryland. It was part of the StreamTime LIVE network and had been installed to monitor activity at the Port of Baltimore. This unexpected footage became a significant record of the event.

So the camera was 3.5 miles from the bridge and 7 miles from the Seagirt Marine Terminal which is visible in the background. Clear weather in a nautical sense and no rain or high winds.

So we can say that weather was not a factor.

I have done boating at night in other areas of Chesapeake Bay and there are all sorts of lighted buoys and fixed beacons all over the areas where boats can go. We had a pencil beam halogen spotlight that could illuminate reflectors on channel markers 5 miles away. A private sailboat 32 feet long.

Lighted channel markers can be seen on the chart of the harbor that has been posted and linked in the post that I quoted.

Ships nowadays also have high-tech radars and GPS tracking systems.

Nighttime in and of itself is no excuse for wrecking a boat.

[jeffandnicole]

I skimmed a lot of what was said, but I did catch this...

The chief difference was that the Baltimore incident happened in clear weather and in a channel that was tangent (straight) from Fort McHenry all the way to 2 miles east of the bridge. So especially for an eastbound (outbound) ship like Dali there are no channel bends even remotely near the bridge.

Left out of this was the incident occurred at night, which is a very important detail.
Left out of this was the incident occurred as the ship lost, regained, and lost power again, which is a very important detail.
Weather may have been clear.  Darkness makes viewing objects and obstructions harder.  Electrical issues on the ship further impacted the ability to go straight.

I didn't go deep into what happened in Baltimore in that post. My quote sums up that it was gross and criminal negligence that a cargo ship was operated that way in confined waters.

I don't know whether the weather was clear in the sense of a cloudless sky. But ..

The camera that captured the collapse was mounted on a home in Riviera Beach, Maryland. It was part of the StreamTime LIVE network and had been installed to monitor activity at the Port of Baltimore. This unexpected footage became a significant record of the event.

So the camera was 3.5 miles from the bridge and 7 miles from the Seagirt Marine Terminal which is visible in the background. Clear weather in a nautical sense and no rain or high winds.

So we can say that weather was not a factor.

I have done boating at night in other areas of Chesapeake Bay and there are all sorts of lighted buoys and fixed beacons all over the areas where boats can go. We had a pencil beam halogen spotlight that could illuminate reflectors on channel markers 5 miles away. A private sailboat 32 feet long.

Lighted channel markers can be seen on the chart of the harbor that has been posted and linked in the post that I quoted.

Ships nowadays also have high-tech radars and GPS tracking systems.

Nighttime in and of itself is no excuse for wrecking a boat.

So lighthouses were a waste of an idea?

[Beltway]

I have done boating at night in other areas of Chesapeake Bay and there are all sorts of lighted buoys and fixed beacons all over the areas where boats can go. We had a pencil beam halogen spotlight that could illuminate reflectors on channel markers 5 miles away. A private sailboat 32 feet long.
Lighted channel markers can be seen on the chart of the harbor that has been posted and linked in the post that I quoted.
Ships nowadays also have high-tech radars and GPS tracking systems.
Nighttime in and of itself is no excuse for wrecking a boat.

So lighthouses were a waste of an idea?

A battleship was on exercises at sea in heavy and stormy weather.

The ship's captain, a highly decorated admiral, was on the bridge when he noticed a light in the distance. The light appeared to be on a collision course with his vessel. He instructed his signalman to send a message to the approaching light:

"Change your course 20 degrees starboard."

The reply came back quickly: "Recommend you change your course 20 degrees starboard."

The admiral was annoyed by the reply and ordered another message to be sent: "I am an admiral. Change your course 20 degrees starboard."

The reply was curt: "I am a seaman second class. Recommend you change your course 20 degrees starboard."

Now infuriated, the admiral sent one final, authoritative message: "This is a battleship. Change your course immediately!"

The final reply came: "This is a lighthouse. YOU change YOUR course!"