7 Years Later
It's been a while since I've posted anything here. A lot has happened.
I finished my glass over foam pedal boat in 2016 - seven years ago - with a pair of derailleurs and 6 speeds. It worked pretty well with a Willoughby 2 blade folding propeller, and even better with a Cadence 3 blade prop. By better, I mean the shaft motion was a bit smoother. Both worked to move the boat forward with roughly the same amount of effort.
After a couple of years of racing on salt and fresh water the freewheel hub axle bearing on the intermediate jack shaft disintegrated during a recreational outing on Lake Union and the Ship Canal in Seattle. It was good that I always carried a paddle and a cell phone with me, and was "rescued" by my lovely wife.
I replaced the derailleurs and intermediate jack shaft with a 11 tooth sprocket on the gearbox and a laser cut stainless 72 tooth large sprocket/chain ring. Fewer parts, less drag, lower weight and higher reliability. I have more 72 and 74 tooth chain ring blanks available if anyone is interested!
Stainless steel push buttons work very well to secure fiberglass tubes within slightly larger diameter fiberglass mounting tubes.
Kick-up/pull up rudders and propeller shaft struts that can be raised and lowered make beaching a joy. I have no worries about launching or landing the boat.
Having the propeller within easy arms reach while seated makes it trivial to determine if the propeller or strut are fouled, and easy to remove anything fouling them. Pulling on a line attached to the pull-up rudder makes that simple, too.
I've had some of the welds fail over time. One was noticed just before putting in, and was located on one of the tabs used to secure the aluminum rail to the hull. That was easy to simple sand down and re-weld. The other failure occurred near the end of a race when I made a tactical error and ended up jammed against a log boom due to tidal currents with a ball of weeds around the propeller. The log boom was between one outrigger and the hull, and the current was too strong and the water too full of weeds for me to go into reverse and back off. Trying to push against the boom only ended up getting the boat into the wrong angle where the current plus the boat ended up prying the outriggers away from the hull. Again, easy to repair.
Adding rudder limit stops at 45 degrees on either side works wonders when going in reverse to prevent the rudder from acting as a brake. It also helps limit braking when going forward when you still want to turn as quickly as possible.
After 6 years the cheapo stamped steel bearing between the 11 tooth sprocket and the gearbox finally died. It was replaced with a stainless ceramic bearing, which should last "forever".
The 0.5" stainless tube I am using as a coupler between the 0.375" gearbox shaft (with an aluminum puck with a 0.5" hole drilled, and with a set screw going through the tube to a flat on the gearbox shaft) and the 0.5" diameter shaft 11 tooth sprocket works pretty well. I find it to be a little noisy at times, but ... it works.
The chain needed a bit more tension to keep it from falling off, so I added one.
posted by Michael Lampi @ 3:29 PM
3 comments
