“Our boss, Joe Batt, liked the idea,” said Labranche, “and encouraged us to give it a try. He also agreed to finance the project. It took time to come up with a feasible design, engineer the propulsion system and drive train, scrounge the parts and then begin assembling the raft.”
“Karys found a person in Waynedale with a collection of bikes who was willing to sell us parts. We bought five frames, eight rear wheels, a dozen chains and a dozen derailleurs. We got a bunch of raw metal from Metal Supermarkets and purchased six barrels from Momper Insulation, which were then welded end to end. A frame was added and five lawn chairs attached. The construction was done at my house.”
The team is hoping that its more efficient system using a vintage brass, three-blade, 17-inch propeller from an old Chris-Craft wood boat will give them an advantage over entrants who will be using their arms to propel their crafts
“By using our legs we should have much more power available,” Labranche said.
The group tested the craft Wednesday afternoon and all systems were go. They covered the one-mile width of the 360-acre Hurshtown Reservoir east of Grabill and returned to the boat ramp (two miles) at a calculated speed of 3 mph. They chose the reservoir for the test because, as LaBranche put it, “if anything went wrong, we had no desire to take a swim in the" river.
A dozen bike chains were necessary to make seven drive chains that turn the prop at a speed of 3.86:1 times faster than the main driveshaft, which extends the length of the raft. All four front seats are configured to put power with a ratio of 2.44:1 into the main shaft so for every revolution of the cranks the prop spins about 9.5 times. The person in the rear seat has his own jackshaft running at the same speed as the main shaft. The rear pedals transfer power through a twisted chain onto the jackshaft. That person is also responsible for steering with a rudder and a paddle. In addition, each seat position has a one-way clutch, similar to a normal bike, to make it so one can coast and still allows the chains to stay tensioned properly and prevents someone getting hurt.
“Win or lose, depending on how everyone feels after the race,” Labranche said, “we'll probably store it till next summer, drag it out, tweak it a bit and enter again in 2014.”
Raft raceWhen: 11 a.m. Saturday launch time
Where: Starting near Swinney Park on West Jefferson Boulevard on the St. Marys River
Ends: Rafts must be across the finish line at Martin Luther King Jr. Memorial Bridge over Clinton Street by 4 p.m.