I recently attempted some upgrades to the HMS Plywood, including some bits to make it easier to move to the boat ramp and swapping out the paddle for oars.
This week I give some examples of things that didn't work as well as expected.
The paddle was a bit of a pain to use, as it pushes the boat around as well as forwards. It was also reasonably heavy. So I had a cunning plan cut it in half to make two oars, and then fit a set of row locks.
I bought some castors from Lowes that were a close fit to the shaft of the paddle, removed the wheel and then put a hole through the end of the oar to act as a pivot. This would give the oars two degrees of freedom, which is about right for a rowing motion.
Because I didn't want to row the boat backwards, my plan was to leave the oars pivoted at their end, and use my hands outside the boat to move them. This turned out to be really hard work, because the leverage of the oar goes all wrong. A paddle is somewhere either a class 1 and class 3 lever, depending how it's used, with the mechanical advantage somewhat adjustable by moving one's hands. A traditional oar is a class 1 lever, straight up. My oar system was a pretty poor class 3, giving me half the force out that I put in.
To make matters worse, the castors didn't give the motion I though they would. The axle of a castor is offset from the centre of rotation to give a "castor angle" which makes the wheel stable whilst moving. This made the return stroke really difficult to achieve, as the oar was trying to move in a way it couldn't. One final issue here was that my arms were now closer to any potential 'gators.
In short, this was a complete disaster. Today I unbolted the oars and screwed them to a spare bit of wood to turn them back into a paddle. The boat's now as easy to paddle as ever.
The other modifications were much simpler, and more successful. I put two wheels on the bottom of the boat so I can wheel it around instead of carrying it. I also cut a handle into the back, so that when I do need to lift it, such as into the back of my truck, I have something decent to grab onto. Finally I screwed the seat down, to stop it sliding around.
So it's definitely a mixed bag here. I'm still planning to add something keel-like at some point, maybe some ballast, and a cup holder.