The modifications included stretching the chassis a little (I'm tall), turning it into a 4-seater, changed it to more of a Model T look (instead of the original dune buggy style), and extended the surrey top. Steve, I'm trying to get some time one of these weekends to trailer the pedal car down to St. It's kind of a three-pedal system -- the middle pedal is double sized and shared by the driver and front passenger. For those that have never heard of this type of motor (like me until a year ago) I think those hub motors are incredible -- they look almost like regular bicycle wheels and the motor is actually built-in to the wheel itself.
Right now they're still a little on the pricey side ($600+ not including the batteries), so I was going to wait. Without divulging too much information lest my wife and her friend kill me, I've had four people (3 adults, 1 child) at a total of 540lbs on my pedal car (pictured in the first post of this thread). So, long story made short (too late!), yes, I think this pedal car could easily accommodate your weight and height.

The boat is aptly named due to the fact that it only goes 3-4 miles per hour at a pedaling rate of 50rpm.
91-year-old naval architect Phil Thiel, born in Brooklyn, now in Seattle has created human-powered boats since his teenage years.
Sailors tend to want headroom, as it keeps from being bashed about in rough seas and saves one from an aching back. To Daniel, I love pedal boating because it is generally easier, safer and softer on the body than walking the same distance. Wow, I admire him because in his early teenage years he created this human-powered boat through pedaling. I would probably make it pop up like earlier mentioned (either light weight materials in the pop up or heavy canvas), and might steal the idea of an extra solar panel or two and an electric motor (at least for use in slightly faster water, as most American waters get seasonally quick). Makes a great diving raft, floating raft or fishing raft.  Simple wooden floating boat design mounted to inner tubes or other floating device!

Pontoons built from wood calked with strips of cotton binding tape laid in marine or casein glue. Augustine to cruise around the Oldest City (give the locals something to hate other than the horse carriages). This boat is not that efficient today but this is a great creation or invention history for me. You could also use this basic principal mounted to other small scrounged pontoons or plastic floats.  With the internet available to most everyone today just do a little online searching for smaller pontoon ideas, build the rest from wood and you are ready to start kicking around in the water!
Thiel’s Friend Ship might be more suitable as a live aboard, although I believe it is designed for motor, rather than pedal, power.

Wooden row boat model kit 2014
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