Re: [Electric Boats] Re: wave powered

The post was similar to the totally ridiculous, technically impossible
(with todays materials science/physics) idea of using gyros to stabilise
displacements boats.
Seakeeper is one manufacturer. They work, to a limited level, in planing
boats, by using large amounts of energy to run gyros.

They are totally impossible on displacement boats like trawlers, where
the enegy budget is larger than the carrying capacity of the trawler.
Note: The manufacturer agrees, and of the 51 systems installed,
according to the manufacturer, zero are on heavy displacement boats.

As an example, a seakeeper midrange system is about 50.000 €, uses 4 kw
for 20 hours to spin up, and uses 2 kW continuously to run.
Such a system on a midrange trawler, say 50 ft, 30 tons.
Needs 2 systems. Uses 8 kw for 20 hours to spin up.
Needs an extra 10 kW generator to run.
Costs 4 kW or about 5 l of fuel, per hour, 24x7, with attendant space,
noise, heating.
Requires about 8 square meters for 2 systems, and an extra 10 kW of
capacity, and the extra genny required to run.
Would cost about 150-200.000$ extra on a 600 k$ 50 ft trawler (Krogen,
Selen, Nordhavn), using up about 2/3 of usable space, and 1/2 or more of
carrying capacity at about 5000 kg in mass, including 2 systems,
generator, extra noise insulation, extra engineering (to install gyros
in central location and move cusrrent systems, extra cooling for boat
(you are inputting 10 kw heat in the boat minus ventilation, 24x7) and
coat about 200$/day to run+maintenance, so about 6000$/month +
maintenance at approx 15% per year).


--
-hanermo



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