o'day dolphin sailboat

Why the Baltimore bridge stood little chance against a fully loaded cargo ship

As questions surround the collapse of a Baltimore bridge after a containership crashed into it Tuesday, engineering experts say that while bridges have some built-in defenses against collisions, this one was most likely too extreme to withstand.

“Bridges are and should be designed to withstand ship impacts. That’s typical of the design process,” said Sanjay R. Arwade, a professor of civil engineering at the University of Massachusetts Amherst. 

“But for all structures and all engineered systems, there is a possibility that an event will occur that is beyond what the structure was designed for. And this may be one of those situations,” he added. 

The Francis Scott Key Bridge, a roughly 1.5-mile-long steel arch truss bridge, collapsed into the Patapsco River early Tuesday after a containership struck it. Several vehicles crashed into the water, and one of the country’s busiest ports shut down.

Follow live updates on the Baltimore bridge collapse

An unknown number of workers with Brawner Builders Inc.   were repairing concrete ducts when the ship, called the Dali, hit a support pillar. Six employees are presumed dead .

Key Bridge was ‘fairly unprotected'

Arwade said design codes for modern bridges stipulate "what sort of loads it has to be able to resist.”

“Whenever a design code is written, decisions have to be made about what the most extreme conditions are,” he said. 

Maryland Gov. Wes Moore said the bridge was "fully up to code."

But the Key Bridge was built in 1977, and bridge design and technology have improved since then.

"Since the 1970s, we have a lot of advancements," Sameh Badie, a professor of engineering at George Washington University,  told NBC Washington. But he said, "I saw today a couple of videos before the collapse, and it seems to me, structurally wise, it was very safe."

Roberto Leon, a structural engineer at Virginia Tech, said that while engineers try to account for “extreme events” during the design and construction process, “when this bridge was built, there were no ships of this size.”

“This type of load was not really considered,” he said. “So the bridge was, I would say, fairly unprotected.”

Retrofitting older bridges could cost millions

Officials have not specified what type of protective infrastructure, if any, the Key Bridge had. 

Leon said that on a newer bridge, large concrete structures called dolphins are often used to protect the base. Dolphins can form a kind of frame and are designed to take the impact of a vessel and “slow the ship down and redirect it away from the bridge,” he said.

“In some cases, they’re called sacrificial elements, because they might be damaged beyond repair if an event of this type occurs, but of course, they save the bridge,” he added.

John Pistorino, a structural engineer in Florida, said dolphins are in use to protect the Sunshine Skyway Bridge in Tampa, Florida, which was reopened in 1987 , seven years after it was hit by a freighter. Thirty-five people died after the bridge collapsed into Tampa Bay.

Pistorino, who was involved in the construction of the rebuilt Sunshine Skyway Bridge, described dolphins as walls or guardrails.

“They can be concrete or steel … and they go all the way down to the bottom of the river,” he said. “They’re supposed to protect the abutments.” 

Jacksonville, Florida, Mayor Donna Deegan cited the dolphin infrastructure that's in place to protect the Dames Point Bridge — the only bridge in the city that cargo ships sail under — in a statement Tuesday. She noted that the bridge is also equipped with specialty sensors that provide real-time information about the distance between the water surface and the bottom of the bridge structure over the main channel.

Older and more vulnerable bridges can be retrofitted to add defensive infrastructure like dolphins, Leon said, but building them can cost hundreds of millions of dollars.

“I’m hoping that because of the infrastructure bill that passed, we are going to be able to do projects like this,” he said, referring to the $555 billion infrastructure bill that President Joe Biden signed in 2021. “Putting those into the budget and justifying them is very difficult when you have all kinds of other bridges that are in really sad shape. So it’s just a question of prioritization.”

However, Kevin Heaslip, director of the Center for Transportation Research and a professor of civil and environmental engineering at the University of Tennessee, Knoxville, said the cost of designing bridges to withstand fully loaded cargo ships like the Dali would “be so high that we wouldn’t be able to have any bridges.”

Government oversight of bridges could increase

Transportation Secretary Pete Buttigieg said he has been monitoring the situation in Baltimore. A team of investigators from the National Transportation Safety Board has been sent to the crash site. 

Leon said he hopes what happened in Baltimore will cause port operations to change “quite a bit.” Pistorino said the event may lead legislators to take a closer look at vulnerable bridges in the country and the types of maritime traffic in ports.

“Just like the building collapse in South Florida created a lot of legislation that required a more intimate type of building scrutiny, I think that will happen on the bridges,” he said.

Minyvonne Burke is a senior breaking news reporter for NBC News.

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O'Day Dolphin

• Thread starter Glen Langley
• Start date Aug 28, 2000
• Oday Owner Forums
• Ask An Oday Owner

Glen Langley

I recently purchased a 1962 24' O'Day Dolphin. Does anyone have any information about this model of vessel or do you know where I can find some?  

Info on O'Days You should check out the Unofficial O'Day Home Page. It is listed in the links section of this website. Lots of terrific info on all O'Days. Also, look at goodoldboat.com. They have a directory of information on tons of boats, and contacts for many owners' associations and individuals who love to chat about their boats.  

Justin - O'day Owner's Web

New to me. Glen,This model is new to me. I looked to the web for information, but couldn't find anything for you there either. Could you describe the boat for us? Justin  

Are you sure its an O'Day? I have never heard of this model. I also think O'Day boats did not come into production until about 1970, but I'm learning new things all the time.Don  

An oldie, but a goodie According to the Unofficial O'Day Website, O'Day produced a grand total of 36 Dolphins between the years 1961 and 1967.  

Wow Talk About Unique Mike thats great, always something new to learn. I had never heard of a Dolphin in any of the other forums. With only that few made, and its vintage its no wonder. It never ceases to amaze me the longevity of early plastic boats. I guess they overbuilt them not knowing just how tough FRP is? And perhaps they had their formulations for the resins right too. I'm wondering Glen how the rest of the boat has held up? Fittings, and such?Don  

Dolphin 24 I purchased a 1960 vintage dolphin 24 two years ago. Since then I have been refurbishing it and launched it June of this year. My e mail address is [email protected] if you want to ask any questions or need info.  

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• Sailboat Guide

Yankee Dolphin 24

Yankee Dolphin 24 is a 24 ′ 1 ″ / 7.4 m monohull sailboat designed by Sparkman & Stephens and built by Yankee Yachts Inc. starting in 1968.

Rig and Sails

Auxilary power, accomodations, calculations.

The theoretical maximum speed that a displacement hull can move efficiently through the water is determined by it's waterline length and displacement. It may be unable to reach this speed if the boat is underpowered or heavily loaded, though it may exceed this speed given enough power. Read more.

Classic hull speed formula:

Hull Speed = 1.34 x √LWL

Max Speed/Length ratio = 8.26 ÷ Displacement/Length ratio .311 Hull Speed = Max Speed/Length ratio x √LWL

Sail Area / Displacement Ratio

A measure of the power of the sails relative to the weight of the boat. The higher the number, the higher the performance, but the harder the boat will be to handle. This ratio is a "non-dimensional" value that facilitates comparisons between boats of different types and sizes. Read more.

SA/D = SA ÷ (D ÷ 64) 2/3

• SA : Sail area in square feet, derived by adding the mainsail area to 100% of the foretriangle area (the lateral area above the deck between the mast and the forestay).
• D : Displacement in pounds.

Ballast / Displacement Ratio

A measure of the stability of a boat's hull that suggests how well a monohull will stand up to its sails. The ballast displacement ratio indicates how much of the weight of a boat is placed for maximum stability against capsizing and is an indicator of stiffness and resistance to capsize.

Ballast / Displacement * 100

Displacement / Length Ratio

A measure of the weight of the boat relative to it's length at the waterline. The higher a boat’s D/L ratio, the more easily it will carry a load and the more comfortable its motion will be. The lower a boat's ratio is, the less power it takes to drive the boat to its nominal hull speed or beyond. Read more.

D/L = (D ÷ 2240) ÷ (0.01 x LWL)³

• D: Displacement of the boat in pounds.
• LWL: Waterline length in feet

Comfort Ratio

This ratio assess how quickly and abruptly a boat’s hull reacts to waves in a significant seaway, these being the elements of a boat’s motion most likely to cause seasickness. Read more.

Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam 1.33 )

• D: Displacement of the boat in pounds
• LOA: Length overall in feet
• Beam: Width of boat at the widest point in feet

Capsize Screening Formula

This formula attempts to indicate whether a given boat might be too wide and light to readily right itself after being overturned in extreme conditions. Read more.

CSV = Beam ÷ ³√(D / 64)

From a 1959 S&S design (#1497) to the MORC rule. Similar to the O’Day version. (The earlier hulls for the YANKEE DOLPHIN where molded by O’Day. Yankee eventually used one of these to built its own mold.) This design, with some modifications, was built by a number of builders. A wood predecessor was called the MERMAID 24.

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