‘Strange dichotomy’: Carriers slowly coming around to safer propane trailer

NAVASOTA, Texas—Exosent Engineering manufactures MC-331 tank trailers that are more driver friendly, more fuel efficient, and—most importantly—safer than a traditional “bottle” trailer used for transporting liquified gasses. So, carriers that haul these liquids are hastening to adopt Exosent’s radical pressure vessels, right?

Oddly enough, that hasn’t been the case, laments Uv Doron, Exosent owner.

“You can buy a transport that’s 30% more stable,” he said. “That’s fantastic, right? Yet we see this reluctance from the industry to adopt. It’s like, ‘Wait a second, I don’t trust that. I don’t know what that is.’ So, on one hand, fleets are striving for safety and driver comfort, but on the other, they don’t want to try anything different.

“It’s a strange dichotomy I see in decision makers—and it’s a tough nut to crack.”

Fortunately, a growing group of innovative fleets like Ryan Bros., headquartered in Thermopolis, Wyoming, who are open to new ideas, are helping drive adoption; and insurers like PT Risk Management in Phoenix, Arizona, are upping the ante by offering discounts on premiums to clients who deploy Exosent’s trailers.

“We’ve been in business a long time [since 1958] but being a small fleet, we’re always looking for new ways of doing things,” said Matt Ryan, vice president of Ryan Bros. “I’ve never been satisfied with ‘That’s how we’ve always done it.’

“So, that drew me to Exosent as well. I like trying new things.”

Creative mind

No doubt, Exosent’s trailers are unique. But so is their co-creator, and as Ryan realized after getting to know Doron, 50, that’s a good thing.

The third-generation steel fabricator served in the Navy, then joined his father’s business, Domatex, which made roll-off containers. He worked as a welder and operations manager before opting to pursue higher education. He earned a Bachelor of Science in mechanical engineering from the University of Texas at Austin, where he helped redesign the fluids lab; and a Master of Science in mechanical engineering from rival Texas A&M, where his graduate work involved fluid dynamics, and he spent eight years as a professor.

Doron, who keeps a framed picture of Albert Einstein in his office—though he’s more like Alexander Graham Bell in appearance—started Exosent in 2010 after completing his master’s degree. He worked on engineering designs for nearly two years, and used computational fluid dynamics to study trailer air flow, with help from his A&M students, before tiring of making drawings. “I need to see things built,” he explained.

Exosent started producing water tanks in 2012. A year later, Doron and co-creator Andrew Duggleby discovered pressure vessels—and inspiration struck. “We realized, wait a second, these traditional tank designs, which haven’t changed much in over 60 years, are rolling over, and that’s costing fleets a fortune,” he recalled. “So, we did a little more research and found this tank design with a lower center of gravity in England, and I thought, ‘Why aren’t we doing this in the U.S.?’”

Challenge accepted

For one, dealing with high-tensile-strength steel isn’t easy—and Exosent uses only quenched-and-tempered carbon steel sourced from Nucor, North Carolina. “Manipulating that steel, and forming it into these complex shapes, is not a given, and actually is a challenge,” Doron said. “Traditional designs with just a cylinder are much easier to fabricate. It’s easier to roll a can, easier to assemble a can, and all around easier. So, we understood the reluctance to delve into this safer vessel, but we liked the challenge.”

Exosent now specializes in torpedo-shaped 331s in a variety of customizable configurations, ranging from 10,600-gallon ammonia trailers to 19,600-gallon, seven-axle liquid petroleum gas (LPG) transports, and Super-B butane haulers for Canada. The company also makes bobtail propane units, fiberglass reinforced plastic (FRP) trailers, and dry bulkers for cement storage and hauling barite—all inside a brand-new plant. “We’re a one-stop shop,” Doron said. “Everything happens at our shop, from start to finish.”

Previously, Doron toiled inside a 20,000-sq.-ft. shop in nearby College Station. As of March 2022, Exosent boasts 71,600 sq. ft. of manufacturing space split between three structures: A 55,000-sq.-ft. main building, a 12,000-sq.-ft. paint and “dressing” facility, and a 4,600-sq.-ft. office, all situated on 27 rural acres. With seven total bays, the plant can accommodate up to 25 units at a time, and the company’s 35 employees produce 50-60 cargo tanks per year, including the end caps, which are made using SBMF Machinery’s hydraulic dishing and flanging machines. “The production of end caps goes up and down with oil and gas,” Doron said. “If oil goes up, you go to the back of the line, and prices can change overnight.

“That inflexibility led us to invest in our own machines.” Those investments, in turn, inspired confidence in Matt, showing him Exosent is ready to ramp up production—and support his fleet long-term.

“They’re well set-up now,” agreed Frank Thompson, PT president and CEO.

The first low-center-of-gravity tank was patented in 1931, and European manufacturers adopted the design in the 1980s. Exosent further modified the “drop-deck” tank design, adding the cone-shaped rear-ends that maintain the proper weight distribution between the trailer’s axles and tractor’s drive axles, “perforated” baffles that act as liquid shock absorbers, air foils for improved dynamics, raised and protected plumbing for easy operator access, and enclosures that shield sensitive electronics. “Anything that can practically be done to help maintenance people, drivers, and the motoring public, we’ve done it,” Doron said.

Exosent also adds heavy-duty rear impact guards to its trailers and maintains a shell “corrosion allowance” of up to .01 in., per American Society of Mechanical Engineers (ASME) and Department of Transportation (DOT) standards. “They won’t rupture, they won’t explode,” Doron vowed. They won’t weigh fleets down either. Exosents on average weigh the same or less than traditional bottles, Doron said, and Exosent’s newest 10,800-gallon vessels check in at 20,800 lbs., permitting operators to pack on more propane.

Matt insists any weight difference in his Exosent trailers is negligible.

Starship-level safety

“The biggest thing we have noticed is the increase in fuel economy,” he said. “Our Exosents, spec’d out against a traditional multi-axle bottle—we run primarily eight- and nine-axle units—are getting approximately half-a-mile-a-gallon better fuel economy.” By Matt’s estimate, that saves the company $20,000 per unit each year.

Doron credits the air foils and lower center of gravity for the fuel economy improvement. “Funny enough, we saw that if we added an airfoil—people call it a spoiler—to the rear of the trailer, we could clean out the turbulence, so much so that, on average, our trailers, with a full aero package, get anywhere between 15-18% better fuel economy,” he said.

“That’s a motherload of money at the end of the year.”

The trailers’ low-profile stance decreases their center of gravity by more than a foot, reducing the likelihood of a rollover, and removes the “sail” holding back drivers with taller tank trailers, which makes them ideal for high-wind zones. Tip-overs are further mitigated with Wabco’s roll-stability technology and Pressure Systems International’s (P.S.I.’s) tire inflation system, both of which come standard on Exosent trailers.

“In 2007, DOT released a massive study, which is on our website, where they talk about all these rollovers, and what can be done to address the problem,” Doron said. “You know what the conclusion was, after 265 pages? ‘Boy, if you could lower the center of gravity, that would be awesome.’ So, we did it. It was attainable.”

The baffles aid with single-compartment weight distribution, and eliminate surge, Doron said. “The baffles are integrated with our rear design, so when you accelerate, the fluid can’t go back because it’s in hydro lock, and when you decelerate, the fluid wants to go forward, but it’s got a ‘step,’ and it’s a small compartment, so it can’t. Now you’ve got drivers pulling full trailers who don’t feel like they have liquid on board.”

Thompson is so convinced in Exosent’s safety benefits, he offers clients who use the trailers a 20% discount on their collision and liability premiums, savings he says earn PT Risk a return by reducing emergency response-related payouts. The tanks don’t tip over, after sliding into ditches, or in situations where roll stability isn’t effective, eliminating cleanup and up-righting costs; and the rear guards protect the tanks even in high-speed, rear-end collisions, ensuring any damage is “very minimal,” he maintained.

“That’s what makes us want to give users a discount,” Thompson said.

“And we do it for two reasons: The trailers are safer—and deploying them gives us a strong indication their owners truly care about safety.”

No laughing matter

Matt says some Ryan Bros. drivers initially were leery of Exosent’s trailers. Now they all want the new units that arrive. “After pulling them, they don’t want to go back to traditionally designed bottles,” he said. Ryan Bros.—led by Matt, dad Tom Ryan, the president, uncle Bob Ryan and brother Sean Ryan, both corporate directors, and brother-in-law Quinton Hetzel, who oversees the maintenance shop—serves customers throughout the Intermountain West with 66 trucks and a diverse fleet of 160 trailers. They haul propane for residential, commercial, and industrial heating in 22 331s—11 of which now are Exosents. Two more are on order for this year. “I anticipate we’ll continue upgrading our fleet until we’re entirely Exosents,” he said.

Now those “different” trailers are a differentiator—with drivers and customers. But a trend they started is taking hold.

“It’s gotten to be where a lot of people in our region have them,” Matt said. “We were the first ones around here, but I’ve noticed a lot of our competitors are pulling Exosents now, too.”

Others, he said, likely never will make the switch. “A lot of people won’t just because they’re too radical,” he said. “There’s certainly some brand loyalty among carriers also. They probably won’t change no matter what. The other thing is, in the propane world, there are trailers from the 1950s and 60s that people have refurbished and continue to use. So, the depreciation isn’t there like it is in a lot of other trailer segments.”

PT Risk, which has “hundreds” of propane-industry clients across the U.S., manages 35 accounts with Exosent trailers.

Doron is doing all he can to encourage adoption, taking the trailers to trade shows—a Ryan Bros. Exosent trailer will be on display at the 73rd Annual Western Propane Gas Association Trade Show and Convention May 15-19 in Palm Springs, California—and adding “pizazz” like the functional rocket-shaped air tanks. “We’ll do anything to make our trailers attractive,” Doron said. “If you can make drivers’ lives more enjoyable, why wouldn’t you?”

Doron certainly enjoys what he is doing—even more so now that carriers are realizing Exosent’s “revolutionary” designs aren’t a gimmick. “I was the laughingstock of the show floor at the first National Tank Truck Carriers show we did in 2015,” he said. “I was nothing but a joke.

“Well, it’s no longer a joke—and those who laughed at us aren’t laughing anymore.”