Just now at the very end of the swimming season I have invented an underwater tripod. And it’s oh so simple. I only need a short plank, a bit of rope, a plastic bag and a stone.
The elastic arm band of my camera goes around the plank. Both float. The rope goes down from the other end of the plank to de stone bag. The camera now hangs from its buoyancy, stable, but susceptible to currents. The closer to the surface the more subject to movement. On my last swim I tried it out. The idea was just to swim dive before the camera. The wide angle lens would have sufficient panorama and so I could engage in a body language parley with the dolphin, hands free for a cuddle and a toy with both of us in full capture.
I had not foreseen that the camera, strung on only one rope, could turn around its axis. And that it did. Dusty wasn’t around, so I could practise at my ease. But wherever I swum, the camera kept turning to and fro and mostly away from me. Something I can easily fix with a second anchor stone. It’ll have to wait until spring, something to look forward to.
And what’s more, I want to make a new waterwing. When I look at how flexible the tips of the pectoral fins of a humpback whale are and how the ‘wings’ of a manta ray work the water I can’t help feeling the extra push. Flexible flaps have always been a mild taboo to me. Between up and down lies a dead moment, the turning of the flap. I can’t reason this out, have to experiment with this.
Also the waterwing is very heavy. This is not convenient on land, particularly if access to the sea requires balancing across rocks or exit requires climbing. In the water the wood needs a coil of lead around the handle in the middle to counter the buoyancy, but let it just float so I can find it back at the surface. No matter however light material I use, the shape displaces a volume of water that has to be compensated by the weight of that material plus the weight of the lead, Archimedes. The less the material weighs, the more lead the wing needs.
Years ago I thought to solve this by making a hollow waterwing of glass fibre with epoxy where water could flow in and out freely. That was much lighter on land, but in the water I still had to move the full volume and therefor weight.
The only variable with tolerance is the volume. But the leading edge has to be half round with 4 cm diameter, or the wing will want to ‘cut’ and be less fluent to steer up and down. That edge should taper to the trailing edge. Any deviation of a lightly bulging, tapering profile would cause drag, but considering the advantage I could make a concession there. With the proper flexibility of the flap the pressure side will assume the ideal line.
My art course has begun again and I’ve started off with drawing flukes to get a handle on the basics of flap propulsion. And I have even made a step back to painting moving water, aka waves. Back are the days that I dreamt myself through the water in weightless resistance, every finger and toe in touch with the water, gliding, pushing and heaving. I need marine plywood, seaworthy glue and a sheet of glass fiber, or preferably, carbon fiber, and time.