But True.

Pedal Canoe and Pickup

A unique device, the "pedal-powered-pickup (PPP)" featured front-wheel drive, front-wheel steering, brakes on the front and two of four rear wheels, and a 7 speed gear setup (high gear: 24Tx12T, low gear: 24Tx40T). Capacity was 750lbs., proven through hauling a Datsun 240Z long block 6 CYL engine several blocks to a repair shop. Wheels were aluminum bicycle motocross, and the entire frame was brazed and welded steel.

Loaded on the PPP (but facing backwards for the photo) is the tandem pedal powered canoe. One long chain wrapped over two recumbent positions to a 2:1 step-up sealed right-angle drive at the stern. The right angle drive was a commercial unit. It had three shafts with keyways, one going all the way through and one sticking out of only one side (like a "T") The sprockets were keyed as well, so I used square keys, plus the allen screws in the pulleys to keep them from slipping off the shaft. The unit was all ball bearing, with seals, with an aluminum case. It survived LOTS of exposure to water and still feels pretty smooth. It was filled with grease, and was rated (if I remember) for 1/2 horsepower.

The right angle drive unit was a "Hub City" model AD 2/5A, style A or B, 2:1 ratio. I cranked the low speed shaft and hooked the high speed shaft to the propellor. To accommodate alignment differences between this unit and the propellor shaft, I used a Gerbing polyurethane three piece coupler, model G-100 for a 5/8 shaft. The input sprocket I used has 9 teeth, and I think I used #40 chain (sorry, I do not have a sample of the chain to be certain). The company I bought it from had !! stainless steel !! chain in the correct size, but I used well-lubricated regular chain with no rusting. I lubricated the chain with Keystone (I think that was the brand, it was 15 years ago!) semi-fluid synthetic tacky grease. Warning: if you have two strong pedalers you had better have at least a 180 degree wrap on that sprocket of the chain will jump off!

An aluminum tube with press-fit ball bearings was fiberglassed through the stern of the canoe, and seals were fitted around the 5/16" stainless propellor shaft. A plastic 9 inch propellor (pitch unknown, but the highest pitch possible was chosen) provided the thrust, while a cable operated rudder provided directional control. Total gear ratio was [ 60T chainwheel X 9T cog X SpeedDoublerRightAngleDrive ] = approx 13:1. Pedal max was about 150 RPM (exciting, let me tell you!) giving a prop speed of 2000 RPM. Static thrust, measured with a bathroom scale being held by two volunteers on the dock with the canoe nose against the vertically-held scale, was 38 LBS. The volunteers were surprised ;-)

From a standing start, the prop would cavitate badly when a sprint was started. Then the canoe would begin to plane (I am not kidding) and the weight would shift to the rear, lowering the stern deep enough to give the propellor full bite. The rush from this high-speed "splash-out" was incredible!

The supports for the cranksets were T6 aluminum scrap 1/4inch thick, mounted to an aluminum channel "spine" running the length of the canoe on the bottom. Pedals were based on Schwinn forged cranksets, bearing sets and the extra-large chainwheels from Schwinn exercise bikes. The chain was industrial heavy duty with industrial idlers keeping the chain path correct. The recumbent pedaling position was extremely comfortable and made for a very stable ride, as both pedalers were sitting on the bottom of the canoe. It is important to note that the cranksets were mounted "out of phase", resulting in smooth power and minimum torque peaks. This benefit can only be realized when there are two or more pedaling positions. Single rider operation was possible and worked well from the rear position. While underway, either person could remove their feet and relax, while the remaining crew member continued to pump. At low speeds the effort for one out of two pedalers was quite reasonable.

Burst speed (canoe): A stopwatch-measured 10 miles per hour past a 150FT dock with a flying start. No other human-powered watercraft I encountered could match this speed (though I am aware of hydrofoils and other exotic craft elsewhere that have gone much faster).

Cruise speed: An easy 5 miles per hour, sustainable indefinitely, but fast enough to leave kayakers panting to keep up.

Both devices were used together to get from home in Portland, Oregon to the Wilamette River about a half mile away, where the canoe terrorized waterfowl, confounded kayakers, and generally ruled the waves for several years.

An interesting note for you experimenters: During initial testing, the 12v motor used in the Pedal Generator was hooked directly to the propellor shaft with 2 in. of fiber-reinforced automotive gas line and some hose clamps. Two car batteries provided the power (and added quite a bit to the canoe stability) resulting in a quiet, smooth cruise of about 6 mph. Voltage was 24 to a 36v rated motor, current was about 10 amps. I ran as long as 4 hours at a time and still was able to start the car with the battery when I was done. The motor barely got warm. The propellor was a small 6 in. 2 bladed aluminum for these tests, turning at about 2000 RPM. The rudder had not been installed at this point, but the canoe could be steered quite well by leaning hard in the desired direction. Indeed, the setup proved so stable that I could stand up (fully) on the canoe seat and "slalom" the canoe by leaning right and left. This activity was not practiced frequently due to the inevitable results of tipping the canoe too far over with 120 lbs. of lead-acid batteries on board.

If I ever get time again (the Silicon Valley pace is sure hectic!) I would rebuild the canoe, but I would not use a propellor in the next version. The prop was very exposed and I was worried about dragging the canoe up on the beach, underwater rocks, etc. The next version would definitely have a pedal powered water pump and be jet driven. I would give away some of the efficiency in return for the benefits:

Status: The canoe lives on (minus the machinery) on the lake at McCall, Idaho. The right angle drive is in my garage, waiting for another chance at glory. The rest of the equipment was sold at garage sales prior to job-related moves. The pedal-powered pickup was dismantled and parts were used for other projects.

                                     Bow ->
                               _                                  _
                              / \                                / \
  ||\                       /  _  \                            /  _  \      /
 / | \   X                 /  / \  \    X                     /  / \  \    /
/ / O \___________________/0_/___\_0\________________________/0_/___\_0\__/
| | ===\__|||____________________________________________________________/
|_| O      ^Right angle drive

0 = Chain Idler
+ = Crankset
X = Seat (Recumbent position)

Here are some other photos. Some show detail of various parts of the canoe, and some are close-ups of the front of the pedal powered pickup. The last photograph shows the pickup hauling the canoe and the pedal generator. This rig won "Most Unusual Vehicle" in a Human Powered Parade in Portland, Oregon during the 80's. The vehicle, as shown with the canoe and generator, was pedaled around twelve miles that day to participe in the parade.

canoe1.jpg canoe2.jpg canoe3.jpg canoe4.jpg canoe5.jpg canoe6.jpg canoe7.jpg canoe8.jpg pedgen1.jpg ppp1.jpg ppp2.jpg ppp3.jpg allthree1.jpg

Back To: [ David Butcher's Personal Page ]
This page is hosted by The WEBworks * Copyright 1994, All Rights Reserved