No brakes
It was in 7th grade that current Yacht Design student Alex Barker built his first powered go-kart. He had the “down the hill” type before, but now, for $100, he had a 212cc single cylinder engine from Harbor Freight, and didn’t need to push the cart back up the hill again. Styling was still a skill he was developing, although it did have a spoiler.
It was also his first “development” project, where if things didn’t work, or weren’t necessary, he’d change them. He started with a brake of sorts – a piece of rubber on the end of a lever he could pull and drag across the ground to slow the cart. Except the lever arm was too short, and he bumped his knee on it, so it was discarded.
And when the single wheel drive spun on gravel roads at the family summer house at the Lake of the Ozarks, he knew he needed a new model. A bigger engine, faster, live axle….but still with his (as yet) unpatented “wrench” steering system…and no brakes .
His motorhead passion had been fueled in the power technology class at high school, where they tore down lawn mower engines, and learned how to hone cylinders and re-seat valves. This lead him to a side-gig fixing lawnmowers (and his own cars), although he learned with the former that if they needed more than a tweak of the carburetor to tune up, it was cheaper to buy a new one than re-build the engine. Given this, one may ask why he started at The Landing School in Composite Boatbuilding, and not marine Systems. He’d reviewed the programs and felt he knew very little about composites (see kayak project below), and as such took the more challenging and interesting route.
Composite Boatbuilding would also give him the opportunity to do a better job on a marine project that he’d tinkered away on for the last few years and got running in the summer before coming to Maine, spurred on by the need to have a video of something he’d built for the I^3 scholarship. Alex calls it a “Jet Kayak”. It’s his own design, although now he is in his second year in Yacht Design he is coming to appreciate his approach might be different than the traditional design spiral.
Effectively, it is a 10’ long plank, with a hull shape underneath, and a 90hp Rotax jetski drivetrain. He started with some had drawn concepts (including a twin engine early version). These were then developed into a 3D model, from which section shapes were taken. Low density polystyrene was cut in “lifts” and glued together much as you would for the building of a traditional half model in wood. After covering in fiberglass, making room for the drivetrain, and lots of sanding and painting, the finished platform looked great (styling and color selection had improved from Go Kart V1)
Unfortunately it didn’t go as well as he might have hoped. There was enough horsepower for speeds in excess of 50 mph…but as this video shows it started “porpoising” at around 30 mph. https://www.youtube.com/watch?v=_JCEuAZq5qM&feature=youtu.be
Last year in Composite Boatbuilding Alex made huge strides. During the year in a team of three they built a fiberglass sheathed wooden plug for an 11’ Martha’s Tender. Then a full fiberglass tool.
And after that a boat, complete with clear finished carbon prepreg seats. His grandfather was so impressed be bought the boat when visiting for graduation.
He put all of this to use in his end of year capstone project, and produced a full set of fiberglass molds for the hull, deck, and cover of Jet Kayak MkII. A two week internship with Brian MacInnes and the team in Michigan at Composite Builders (https://www.compositebuilders.com/) enabled him to CNC cut the foam plug more accurately than the previous approach.
Upon return to the school he finished fairing, integrated the jet drive, and produced the female molds…a big ask given the timeframe.
The design was a development of the first iteration, with some expert guidance from none other than Michael Peters, who kindly walked through the challenges of getting a small, high speed craft to be stable. His thoughts on longitudinal center of gravity, hardening the chines, and fine tuning the sections have yet to be proven. This summer the tooling did not get used, although Alex did add a trim tab to the prototype and can report he overcame the porpoising effect…only to have it start chine walking at 38 mph.
The opportunity to know how to make a boat better…without building repeat iterations, and the understanding that there are ways to test ideas before committing to fiberglass work, has seen Alex return to The Landing School for 2019/2020 in Yacht Design. He is now advancing concepts and shapes on Rhino, not using polyfair. The math behind the lines, propeller selection and powertrain is now connecting with what he had discovered by trial and error. The first few months have been focused on sailboats, but his passion lies in powered craft. Fast ones. Without brakes. Upon graduation he hopes for an entry level position in a powerboat design office….or maybe working on a 5 axis CNC machine so he can create shapes for his own projects on the weekend. The pull, back and forth, between drawing it or just doing it will be with Alex forever, and stand him in good stead in design or manufacturing.