Thursday, July 15, 2010

Solar Skiff the Embryo

It was only a matter of time before I outgrew the use of small solar gadgets in the commuter dinghy and moved on to test the concept of pulling my propulsion power from the sun. Not that I consider myself to be breaking ground here - many have done much more in this field. I thank them for the inspiration. I'm quite sure that many others out there right now have worked out similar schemes or are in the process. I guess it was the same for every other mechanical concept from the wheel on up. The project if one of personal discovery and research. It's about answering my own questions and being better at answering other people's questions later.

The slant I am approaching this question from is one I have felt strongly about for some time. It's the half step back, full step forward approach. Prior to the second world war, power densities available were small from internal combustion engines. To compensate, the emphasis was on efficient hull form. These days, emphasis seems to focus on everything but hull efficiency with power installed in unlimited quantities to suit. Seems to me that in applying a low power density propulsion scheme, it would be smart to revert to such hull forms as were used before there was high density power. It's all good and well to drive your inflatable with an electric motor, but since it was designed for planing speed with a gas outboard, you will probably be operating in the least efficient speed range. My tack was to start with a hull designed for the lowest power density - rowing. Specifically, my electric drive conversion is based on a Whitehall hull.



This project has been a slow gathering of pieces from far and wide. Ken Flowers, an exceptional lobster boat builder up in Maine came through with the molded hull shell of perfect dimensions for this small scale beta project. Solar panels and electrical components have been trickling in from E-Bay and other online sources. Wood's Boats in RI came through with an affordable gently used salt water trolling motor. I suppose if you really looked at the overall system energy of this project, it may not really be as close to zero impact as I'd like - what with all the shipping involved. But as with most things, I think what is important is the avenue of thought. It's the channeling of creative energy toward a better solution.

So here's the embryonic version of solar skiff. Not especially pretty at present. and maybe even a bit hard to recognize for what she is intended to be. But for all of that, it's the start to a start. I suppose that in itself warrants documentation. And besides, I'm told it's the progress that gets noticed. Maybe the embryo stage will make later imperfections less noticeable!


Cool Ideas

I’m starting to think that just as cars now are only available with everything that was once called an option, boats are only being offered with bow thrusters, generators, and air conditioning. A quick survey of the weekend arrivals is pushing the 50% threshold anyhow. What happened to sailing to quiet places to be cooled by summer sea breeze and invigorated by a swim and fresh air? I never have been “like the other kids,” but I just can’t see the attraction of going from shore power air conditioning to anchored out generator air conditioning.

Here’s my air conditioning unit. Pretty simple. Think it was marketed as the “Wind Scoop” once upon a time. It’s fairly effective, though it does get a bit wonky in places where wind and tide oppose. The plus side is no generator, no circulator pump, and no compressor. And correspondingly no fossil fuel consumption. The air smells nice too. I don’t think I’d thrive on 35’ of recirculated air. I suppose the downside is not having that sense of security so many cruisers in the era of entitlement draw from a pulsing internal combustion engine.

And another cool idea that needs no juice… latent heat of evaporation is the concept. I think I first read about this in a C.S Forester novel. But I thank good science teachers for my understanding of the concept. In simplest terms, when water evaporates, heat is absorbed. That’s why we feel cold in wet clothes in a breeze, even on a hot day. Applied to the new favored stainless water bottles, this principle provides a refreshing temperature drop, though not the jolt of icewater. My specific setup seems to work well with an old gym sock (preferably recently laundered,) slipped over the water bottle. Fuzzy side out evaporates, hence cools better. Michael Jackson fans might go in for one white glove instead. Same concept. Hang the setup in a shaded spot with good exposure to the wind. Even with refrigeration, this setup is great as it keeps the hydration near to hand, reduces cold loss from frequent refrigerator openings, and makes you feel smart just for knowing the concept! Try it. Some folks will think you strange for wearing 1 gym sock on your water bottle and none on your feet, but they will suffer that thought over a tepid water bottle.

I won't get started on the bow thruster standard option now used in lieu of the rudder and engine for steering...It will just make me cranky.