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A used car alternator.
A plastic housing with watertight bearings.
A ship propeller 20 -30 cm.
A second watertight ball bearing.
300 m of heavy duty cable.
A new car battery.
Take the car generator and add a water-resistant body (2
component resin will work), attach the ship
propeller on its axis,
mount it with a rotating base on a steel tube in a 20 pound
Add a 30 cm vane on the opposing end to do the steering, wire the
cables and place the whole thing on any beach just outside the
Now, any coming wave will spin the propeller, the vaning water
will turn the assembly and spin the propeller again...
There is a little extra effort to be put in the rotating base. We
need 2 isolated copper rings and two carbon contacts to get the
360 degree rotating alternator currents into the base which does
not rotate. You can find the carbon contacts in any discarded
Attach the other end of the cables to the
battery. Careful with the polarity. (in case you wired it wrong,
plus is minus and red is negative!)
Free energy for each beach camper!
Tidal power using horizontal axis turbines at Wikipedia
[phoenix, Jan 02 2009]
||You have no idea what a single rock in the water or
the beach can do to the coastline.
||I cannot find it anymore, but a few years ago there
a presentation about what a single rock can do to the
(now nonexistent Herzlia - Appolonia)
beach. The energy of the incoming water is
sent back taking with it much of the sand, instead of
sandy beaches which lower the energy and cause
sand to continuously build up.
||There's a name for that effect, can't remember what it is,
and it's often found at the core of bullshit NIMBY arguments
against tidal/riverine submerged-turbine generators. There
is a project currently underway in the Bay of Fundy to
install anchored barges with wind turbine towers on the
decks and tidal turbines below. There has been some
narrow but highly vocal opposition to this project, claiming
that the installations will have negative effects on fisheries
and shorelines, to which the US/Canadian joint comittee in
charge of the project has repeatedly replied: "Bullshit!"
||Soon we'll need this kind of devices to extract energy everywhere. I like the idea, in fact; doesn't need the rotating base; the propeller (turbine in this case) can rotate e.g clockwise for incoming waves and counterclockwise for outgoing waves. The car alternator have an internal diode bridge so the DC polarity is always the same.
||sealed bearings? in sea water? under significant
physical stress? with temperature variations? Good
luck. Of course the bearings will not be a major
concern... marine life will have it resembling a rock in
a month... You'd need maintenance on a weekly
basis, and you'd lose it in the first big storm.