Coan Two-Speed Transmission: A Closer Look

The Coan two-speed transmission was originally developed for 3,000-hp dragsters.

The recent speedonthewater.com story, “Project: Remaking Speed Racer,” captured quite a bit of attention, including that of Dave Coan of Coan Engineering. That’s because Coan’s 34-year-old, Kokomo, Ind.-based company designed and built the two-speed tranmissions for the 44-foot-long Marine Technology, Inc., catamaran.

Dubbed the Xtreme Marine Transmission, the predecessor of the two-speed trannies in Speed Racer performed consistently and reliably in 3,000-hp dragsters for years. But that didn’t necessarily mean the transmissions would cut it in the high-performance boat world, where the duty cycles and loads are much different than those for a dragster held at wide-open throttle for a little more than four seconds.

“I’d always had an interest in high-performance boats, but we originally got involved in the high-performance marine side several years ago through (noted engine builder) Keith Eickert,” said Coan. “We eventually ran our transmission behind a 1,200-hp Eickert engine on a dyno, and we found 20 more horsepower than he had with the transmission he’d been using.”

Among the first applications of the Xtreme Marine transmission—and the one that truly convinced Coan the two-speed, planetary-designed product was ready for the go-fast boat prime time—was for a diesel-powered military vessel. Among the specs for the transmission was for it to require no service or repair for 200 hours of operation. The project succeeded, and Coan’s original thinking that the transmission was up to the rigor of high-performance marine use was confirmed.

“We knew we’d have to make some changes, but we knew we didn’t need to take a clean sheet approach,” he said. “The design and technology had already been proven, so we thought we were plenty-safe to use most of the mechanical layout and stay within our existing case. We did have to shorten the drive shaft in the unit and provide an adaptor the existing bell housing.”

Coan continued to work with Eickert “and his associates” on improvements for the unit. Among them was a specially designed deep-sump oil pan.

“That way if the boats get into an extreme angle, the transmission is never starved for oil,” said Coan.

In 2010, the first high-performance marine installation of Coan Engineering’s Xtreme Marine two-speed transmission happened in a catamaran with 1,200-hp turbocharged Chief Engines.

“Since then, we’ve picked up several other high-performance boat customers,” said Coan. “But we never had a high-profile customer like Speed Racer until now.”

The Xtreme Marine transmission doesn’t just offers two speeds in forward—it has a gear reduction in reverse. That makes controlling big-horsepower catamarans (at present the units have only been installed in cats) at the docks that much easier.

“We’ve been pleased with the results,” said Coan. “So have our customers.”