Stern Drive The Invention of the Stern Drive

The Invention of the Stern Drive

The information below comes from patents and the book,
Iron Fist, by Rodengen. It is a biography of the life of 
Carl Kiekhaefer the founder of Mercury Marine. Chapter 26 
(pages 360 to 379) is titled, "The Great Stern Drive Conspiracy."

When Charles Strang was working towards his masters degree at M.I.T. in 1948 he was an avid outboard racing enthusiast. He became interested in mounting an assault on the American outboard speed record (78.121 mph). He realized that horsepower was holding back the record as the largest American OB was the 33.4 HP Evinrude Speedifour.

He found an aluminum car racing engine in Europe called the "Coventry Climax" and was going to mount it to the lower end of an OB and hang it all outside of the boat to be still considered an "outboard." When he discovered it wouldn't be legal, he continued to refine the idea of an automotive engine with an outboard lower unit, but this time with the engine inside the boat and drive unit outside. In his engineering, "invention ledger" he drew various versions of his design and then dated and signed the pages which was M.I.T. procedure. One of those entries in 1948 was for the final version of a modern stern drive complete with the "universal joint" linkage which would ultimately be patented, not by Charlie Strang , but by Jim Wynne. In the explicit drawing he identified the universal torque transmitter by its scientific name, "Hookes Coupling" and labeled and identified the tilt and swivel pin features within the coupling exactly as they would appear on the patent application submitted ten years later by Jim Wynne.

Strang couldn't decide what to call his new drive, he had been a comic book fan in his younger days and remembered a voluptuous siren named Apacinata (Appassionata) Von Climax. Since he had considered joining his drive to the Coventry Climax engine, he named the stern drive the AVC drive.

In the summer of 1951 after working only two weeks for the Kiekhaefer Corporation, Charlie Strang disclosed his idea to Carl Kiekhaefer. These were great times for Carl. He was in transition between the two-cylinder Lightning models and the more powerful four cylinder Thunderbolt models. He was having great success with his 25 horsepower model and was setting his sights on OMC and their even larger horsepower outboards. Strang was passionate about the idea, but Carl wan't the least bit interested. He not only was not interested, but went on to call Strang, nuts and call the idea ridiculous. Then he told Strang it was a "horse _ _ _ _ idea."

Charlie got caught up the all the activities at Kiekhaefer including road racing. He kept thinking about his AVC drive and his new experiences with powerful Chrysler, Ford, and Chevrolet engines being used in stock cars.

In 1955 aboard Kiekhaefer's Beech-18, Charlie Strang and Jim Wynne were flying to Texas to testify in an outboard product liability case. They listened to the Sugar Ray Robinson vs Carl "Bobo" Olson boxing fight on the radio and afterwards the conversation drifted to engineering and the potential speeds of outboard motors. On this flight the greatest conspiracy in the history of the marine industry began.

Charlie sketched up his AVC drive idea who got very excited about it. He talked to Charles "Alex" Alexander about it. "Alex" had been promoted to engineering VP and reported directly to executive VP Charlie Strang. Wynne also reported directly to Strang. A series of secret conversations between Strang, Alexander, and Wynne began discussing the AVC drive and its possibilities. They made the decision to develop the new product themselves, without the knowledge of Carl Kiekhaefer.

Carl and Jim Wynne were close friends at this time (an event involving a woman would end this in 18 months) and he (Jim) was appointed chief engineer of the proving grounds. Charlie was second in command as executive VP, and Alex held the highest engineering position in the company. These three men were actively conspiring to build what would become the most significant product in marine manufacturing behind Carl's back.

In the spring of 1958, Jim Wynne left Kiekhaefer Mercury and in less than 90 days, "invented" the stern drive. Charlie Strang and Charles Alexander remained at Kiekhaefer Mercury and continued to support his development of a prototype AVC drive. A company was formed, Hydro Mechanical Development, headed by Wynne. Unable to raise the huge funds required to tool and produce the drive they began looking for help. In early 1958 they met with John Buehler president of Indiana Gear Works and also the U.S. licensee of the Hamilton Jet Drive of New Zealand. The book tells of the unusual meeting, Buehler was a large man in a boy scout uniform and his huge office had the rear end of animals mounted on the walls with arrows sticking in them. Buehler was convinced that Hamilton Jet Drives were going to take over the industry, so he was not interested.

In Florida, Wynne completed the "cobbled together" prototype in his parents garage. Remembering the importance of secrecy learned from Kiekhaefer, he covered the garage windows and spoke to no one about it until the prototype was completed and tested. He borrowed a 20 foot fiberglass boat from Woody Woodson (founder of Thunder Boat Company in Miami) and installed the new drive. He covered it up and trailered it to Pelican Harbor on the intracoastal waterway in Miami before dawn. After a few trial runs and some adjustments, he was satisfied that the concept would work.

Shortly later John Jarnmark, the New Jersey based general sales manager for Volvo Penta made a routine sales call on Wynne following up on a 80 horsepower engine delivered without the reverse gear. Wynne told him he was working on a new application for the engine that could produce a lot of sales. Jarnmark was interested, but Wynne could not disclose more until filing the patent applications. After they were filed, he invited Jarnmark back and he was very impressed. Jarnmark sent diagrams, photos, and descriptions of the device to Volvo in Sweden.

Wynne was asked by Ole Botved the manufacturer of Botved-Coronet outboard boats and cruisers in Denmark to join him as one of three pilots trying to cross the Atlantic in an outboard boat. He flew to Copenhagen for the preparations and then traveled to Sweden to meet with Harald Wiklund the president of Volvo-Penta from 1949 to 1977. When Jim walked into his office in 1958 he had already been president for 9 years and the company had been growing dramatically. Wiklund was very impressed by the idea. Wynne was still thinking that Charlie Strang would leave Mercury soon and join him in the venture. Now that Volvo was seriously interested, he called Strang. Carl had just proposed that Strang head up a public Kiekhaefer Corporation as president. The war with OMC was in critical stages, and he was very busy; but, he knew the potential of the new drive. If he chose to leave Kiekhaefer, Jim would negotiate to buy Volvo engines at a volume discount, if he stayed Jim would negotiate a license agreement with Volvo for them to produce the drive and market it with their engines. Strang told Wynne, "Jim, do what you want with it."

Wynne met again with Wiklund to proceed to negotiate the licensing agreement. The initial agreement was $7 for each unit produced by Volvo over the lifetime of the patent and 12 1/2 percent of any license income Volvo might receive from other builders. Sales initially faltered and $3.50 per drive was agreed upon. Later Wiklund felt the agreement was too much in Wynne's favor as all he brought was the idea. They had to develop and produce it.

Strang and Wynne agreed that Wynne would receive credit for the invention of the drive to protect Strang's position with Carl Kiekhaefer. They understood that Strang could be held liable for disclosure of the idea while still on Kiekhaefer's payroll. The bond of secrecy between Strang, Wynne, and Alexander would last over 30 years.

At the conclusion of the outboard crossing of the Atlantic, Wynne appeared on the TV program, "I've Got A Secret" and stumped the panel. "Little did they realize, Jim Wynne and Charlie Strang both had an explosive secret that would remain hidden for thirty long years."

As Volvo-Penta began a crash program to produce the AVC drive which they called the Aquamatic, Wynne found he was unable to answer many of the technical questions being posed by Wiklund and their chief marine engineer, Neil Hanson. Wynne had to disclose that he was not the original inventor, that Charlie Strang was, and swore them all to secrecy. During the late summer of 1958 a series of clandestine meetings between them were arranged. Often they were in motels near boat races. Strang was very concerned about Kiekhaefer's spies and his volatile nature. Wiklund said he felt he spent more time that summer in an airplane than behind his desk in Gothenburg Sweden. With Strang's guidance , the drawings were finalized and Swedish engineers rushed to complete tooling in the fall and early winter of 1958.

The Aquamatic was unveiled with a lot of fanfare at the 1959 New York Motor Boat Show in early January. It had taken the Volvo engineers less that 6 months to produce the tooling for the prototype unit. Jim Wynne was a guest in the booth to help answer questions about "his new invention." Ingemar Johansson, the Swedish heavyweight boxing champion made an appearance to pose with Wynne. Carl Kiekhaefer was stunned to see the huge crowds in the Volvo booth and was miffed at dealers asking him about the merits of the new drive. Almost a year later, Carl got his hands on an Aquamatic and installed it on an 18 foot Dunphy Boat and tested it himself at Lake X.

His report, sent to Charlie Strang before the end of January 1960 "was perhaps the most biased, unfair, and clouded evaluation that an engineer could ever have made. " He was steaming over the drive because he considered the concept without merit and because Jim Wynne was involved. He never recalled talking to Charlie Strang about the AVC drive years earlier. Carl's comments on the test report were contrary to just about everybody elses opinion of the new unit.

This test report was only part of a nearly 2 year long tirade by Carl. He was irritated by Volvo's advertising entering into his two territories of speed and endurance. Wynne had learned of the importance of racing and endurance marks while at Kiekhaefer. He obtained one of the 10 prototypes and secretly prepared another Woody Woodson 18 foot Thunderbird Boat for the Miami-Nassau race. He was afraid Volvo would not let him run one of their precious "boat show" prototypes in a race. He took on board as co-pilot Bill McKeown, editor of Popular Boating magazine. That magazine is today called Boating and was very popular at that time. Later Harald Wiklund, Volvo president told him that if he had any idea he was going to race it he would have personally came over and taken it away from him. They won their class in the race and were 4th overall, and received a landslide of favorable publicity for the Aquamatic drive.

As Volvo sales began to eat away some of Carl's 70 HP OB sales and dealers and distributors kept asking when Mercury would come out with a stern drive, Carl asked Charlie Strang to begin thinking about the concept of a Mercury stern drive (we can only imagine how this made Strang feel, as he was actually the secret original inventor of the drive).

In June 1960 Carl tried to negotiate an agreement with Volvo to be their exclusive sales agents for the Aquamatic in the U.S. Carl wanted Volvo to actively enforce its patent to keep others (OMC) out of the stern drive business (out of competition for his OB sales. The deal unraveled when Volvo wanted a guaranteed minimum of 10,000 units a year. If Carl had been successful in his reasoning he would have prevented the expense of tooling up for another drive and protected large HP OB sales.

Sales of the Aquamatic floundered at first. The initial run of 10,000 units only sold 3,000 by the end of 1959. The drive was being highly touted in the press and people liked it but it wasn't moving. It was easy for boat builders to sell boats without engines and the consumer would buy and OB and put it in the boat. Wiklund turned to Ole Botved who had crossed the Atlantic with Wynne in the outboard boat. He agreed to make Aquamatics available interest free for a full year, if he would install them in his line of Coronet boats. It was a great success.

In the fall of 1960 in a Mercury sales meeting, Carl admitted the possibility of a Mercury stern drive, but characterized the concept as a pure loser. In a speech to distributors on January 13, 1961 he finally broke down and told the public that if they wanted it he would build it. Charlie Strang continued to develop the project and Carl didn't notice how easy it was for him (the original inventor). Carl was concerned Volvo would force them on the patent, Strang knew they would not due to secrecy surrounding the original inventor.

Kiekhaefer learned that OMC was also working on a stern drive and would be announcing it at the Chicago Boat Show on March 25, 1961. He moved up Mercury's announcement two days to March 23 followed by a large display in Mercury's booth on the opening day of the show March 24. A week before the press announcement, the name MerCruiser was selected for the stern drive.

OMC's V-4, two cycle 80 HP stern drive called the OMC-480 paled by the MerCruiser four cycle automotive engines with 125 to 200 HP.

Carl took the conservative approach and only sold the drive to engine manufacturers who sold the engine and drive package to the boat builders. Mercury dealers couldn't care less about the drive because they could not market it themselves. Strang remembered when he first got Carl to take the drive seriously. He told him that he and his mother had seen a little 4 cylinder Chevrolet in a local dealership. He took Carl in the next day and told him they needed to put that engine with the stern drive. Carl told him to contact GM. That afternoon they flew to Detroit and brought back the first engine. Carl was still dragging his feet on the idea and Strang told him if he didn't like it to price it and he would buy him out on this project. "Never heard another complaint from him'" Strang said.

Carl wasn't aware that Strang and Charlie Alexander had already tried to raise money to fund the project with Jim Wynne. Carl was about to take care of the strategic errors made by Volvo and OMC of marrying the drive to low horsepower engines. GM's 110 to 140 HP engines greatly raised the market appeal of the drive.

As horsepowers moved up, Kiekhaefer had Strang design two more drives, the MerCruiser I and the MerCruiser II to handle 225 HP and even 310 HP engines. By late 1961, Mercury had captured the bulk of the market by offering two models and a wide range of engines. Mercury began to receive orders from nearly every boat builder in the country.

By 1962, only 3 years after the introduction of the Aquamatic, 16 manufacturers were producing stern drives. When Mercury opened up to direct sales to boat builders they eventually captured 80% of the world market. The conspiracy between Wynne and Strang actually worked to Carl's advantage. This secret relationship let someone else go first and test market while eventually making possible Mercury's entry.

Wynne's patents wouldn't actually issue for ten years because another inventor, C.E. Mac Donald of Seattle had actually constructed a prototype before Wynne's in Miami. MacDonald filed his application just two weeks after Wynne. They claim to be unaware of each others activities and independent discoveries of the same idea. Wynne was awarded the patent (3,376,842) on April 9, 1968. Wynne was rewarded with substantial amounts of cash from the Volvo agreement that was in effect until the patent expired in 1985. Charlie Strang would never accept a penny for his invention and went on to become board and chief executive officer of OMC during Carl Kiekhaefer's lifetime but never disclosed the story of the invention of the stern drive while Kiekhaefer was still alive.

I had the opportunity to meet Mr. Strang at IMTEC97 during the OMC press conference where David Jones was announced as the the OMC president. Coverage of my visit with him and a photo are on our RBBI Coverage of David Jones Named CEO & President page.

The patent itself, #3,376,842, is quite interesting. It was filed on May 11, 1960 (probably actually filed a couple of years earlier and this is the version that survived) and granted on April 9, 1968. It is titled Boat Propulsion Mechanism, lists James R. Wynne of Miami FL as inventor and assigned to A.B. Volvo Penta. It is a well written patent with some very nice drawings and 33 claims. This is an unusually large number of claims. The large number of claims very strongly define the patent, very important when it came to issuing licenses.

We posted this page several years ago and have since been able to speak with several people who were somehow involved in the development of the stern drive, as well as others who had connections to drives that predated the stern drive and shared some similarities with it. Its been an interesting ride. If you had connections to the development of the stern drive or other similar drives that predated it, we would be happy to hear from you. Just drop us an email.

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