# 5m electric power cat plans

Discussion in 'Powerboats' started by nivo7, May 12, 2011.

1. Joined: May 2011
Posts: 11
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Location: israel

### nivo7Junior Member

how can I find a 5m LOA electric power catamaran plans?

i planed catamaran on this prootions:
Lwl - 5 m
Bh - 1m
Bwl - 0.54m
Tc - 0.27m

it has a 200 kg wind turbine 3m high
150kg machinary - (2Xmotors, litium batteries, generator etc.)
NO SAIL

I am trying to make all the calculations for this cat and i need somthing similar to compare the results

if there are plans that include the equations it will be awsome!!!!

anyways thank you all for the help

2. Joined: Apr 2011
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Location: copenhagen

### copenhagenJunior Member

Im unsure what the total width is but om assuming its 5x5 and not 5x1m?

a couple of engineering questions spring to mind; what is the C of G of the turbine?
is your generator mounted at the head of the turbine, as this will add alot of unnesecary weight up high making for an inherently unstable craft

The equations are readily available, you just need to isolate every part and do the calculations for the turbine, hull, electric system as isolated items carrying the variables from one to the other...

now if you are open to suggestions: first of all its not a new concept, there have been several attempts of making an autogyro sail mechanically conected to a propeller before, it has the advantage of being able to sail in direct headwind.. but its extremely dangerous to be on a boat with a spinning turbine in close proximity of the crews heads!

if you connect the turbine to a vertical shaft (or via belt drive like a helicopter tailrotor on rotoway helos) and via a clutch to a moto/generator with a direct prop drive you will be able reduce the batery weight and electrical component weight considerably as it will only be needed in dead calm weather to maneuvre... (and once you get moving you will be assisted by the relative wind...)

also provisions for a spinaker will propably increase the downwind performance (especially with a folding prop) but i wouldnt be at all surprised if it turned out that the added weight of the electrical system over a simple direct mechanical drive was detrimental to performance compared with a "non electric craft" of same configuration

3. Joined: May 2011
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Location: israel

### nivo7Junior Member

the Bh I ment Bh1 the over all width is 3.75
about the security of the turbine i surround it with with a security line so crew members cant touch the turbine.
the generator is in the body not on the turbine.

where can I get a file which summarize all the calculation equations, with a small explenation for every part?

the boat is for a family: 2 adults and 2 childrens
and I hope its weight less then 1000kg

4. Joined: Apr 2011
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Location: copenhagen

### copenhagenJunior Member

3 minutes on google found this :

The Wind Turbine Power Equation is one of the most important equations a beginning wind enthusiast should memorize.

HWP = 0.5 x 1.23 x SA x WV3 x 0.25

(HWP) Harvestable Wind Power (w) = 0.5 x AD (air density kg/cu m) x SA (sweep area m^2) x WV^3 (wind velocity m/s) x cP (coefficient of performance Betz limit 59.26%, R^1 or Copper loss, linear power curve to cubic curve matching — 0.25 for most systems)

Conversions:

1 square foot = 0.09290304 square meters
1 mile per hour = 0.44704 meters per second
1 kilometer per hour = 0.277777778 meters per second

Equation for a HAWT with 17′ diameter blades in 10mph wind.

17′ Diameter Blades (21.07m2 ), 10mph average wind (4.47m/s)

HWP = 0.5 x 1.23 x 21.07 x 89.31 x 0.25
HWP = 289W

i would stick to sails... and i would under no circumstances rely on a safetyline to keep my childeren from getting fatal head trauma at sea !

5. Joined: May 2006
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Location: us

### bbsboatJunior Member

and I hope its weight less then 1000kg?
for such so small boat ,the displacement must be less than 1000kg

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