| Concept for 2 types of Zero Emission Yachts | ||||
| General ship data | Type of yacht | Mono-hull | Catamaran | mass / size and some other data derived from similar-sized
boats' data, for mono-hull (left
column): Sunseeker 75
(http://boatpoint.ninemsn.com.au/reviews/2005/motoryacht/sunseeker/sunseeker-75-yacht-8652
), for the catamaran (right column): Lagoon Power 43 (http://www.powerandmotoryacht.com/boattests/0202lagoon43/index2.aspx and http://www.lagoonpower.com/UK/frameset_uk.html ) |
| LOA (length overall) in metres / feet | 23m / 75ft | 13m / 43ft | ||
| number of passengers incl. crew | 12 to 16 | 5 to 7 | ||
| Total mass (kg) | 45000 | 12000 | ||
| Total cost estimate | 3.000.000 € | 500.000 € | ||
| Low speed (displacement) mode, vessel powered by electric engines | estimated average 'low speed', i.e. in displacement mode when vessel is powered by electric engines (knots) | 8 | 6 | figures
derived from electric boats, e.g. http://www.hdsolarschiff.com/de/technik.htm |
| required specific power for low speed (displacement, no planing) for electric engines to achieve the speed entered in the line above (kW / 1000 kg) | 1,2 | 1,2 | ||
| calculated required 'low speed (displacement) mode' power, i.e. when vessel is powered by electric engines (kW) | 54 | 14,4 | ||
| High speed (planing) mode, vessel powered by kite(s), if wind speed => 20 knots (5 Bft.) | 1st
approach to calculate specific kite sail size: (a) required specific power for planing cruise at average planing speed mentioned below at 'Voyage data' (kW / 1000 kg) |
49 | 30 | derived from data of boats mentioned above, links in line 'Total cost estimate' |
| 1st approach to calculate specific kite sail
size: (b) kite sail replacement factor: kite sails area required to replace combustion engine power for achieving planning cruise at wind speeds >= approx. 20 knots ( sqm / kW) |
0,67 | 0,67 | This
figure has been derived from experience published by www.skysails.de in
http://www.skysails.info/fileadmin/user_upload/Pressespiegel/2009/Deutschland/090115-Schiff_und_Hafen-Testergebnisse_des_SkySails-Systems.pdf
. However, many parameters are different here from the situation at Skysails where kites only SUPPORT cargo ships being pushed by combustion engine powered propellers in DISPLACEMENT mode (at low speed). The altitude of wind tapped here should be similar (> 100 m above the sea with stronger and more constant wind). This figure will, of course, be less if planing mode is supposed to be achieved not at a wind speed of 20 knots (5 Beaufort), but only at a higher minimum wind speed, e.g. 25 knots (6 Bft.). |
|
| 1st approach to calculate specific kite sail
size: (c) calculated specific kite's size to achieve / maintain planing cruise at a wind speed of at least 20 knots (sqm / 1000 kg) |
32,67 | 20,00 | Result of 1st approach to calculate specific kite sail size | |
| 2nd
approach to calculate specific kite sail size: compare with kitesurfers' sail size (sqm / 1000 kg) |
80,00 | 80,00 | This
figure has been derived from observation of kite sizes selected by
kitesurfers at a wind speed of 20 knots. A kitesurfer (approx. 100 kg incl.
equipment) would use a 6 to 10 sqm kite which results in a figure of 60 to
100. However, direct use is not possible due to: - there's a completely different scale and shape of a kitesurfboard compared to yacht - typical kitesurfer's leashes are approx. 20 to 25 m long, while here we would tap stronger winds from an altitude of more than 100 metres - automatic control of kite's flying behavior is more efficient than manual control Thus this figure cannot be used directly either. |
|
| average value of 1st and 2nd approach | 56,33 | 50,00 | For further calculation, the average value of the 2 lines above is used. | |
| calculated kite's size to achieve planing cruise (sqm) | 2535 | 600 | Manufacturing very large kites and appropriate automatic control equipment will probably be the biggest technical challenge of the project. Currently, largest skysails.de kites are sized 240 sqm (360 sqm planned). Using several kites will presumably be necessary as sailing area has to be reduced in very strong winds; controlling several kites for optimal combination of kites' pull will be a challenge as well. | |
| Voyage duration | Distance (nautical miles): | 3200 | 3200 | typical distance of a North Atlantic coast to coast cruise |
| estimated average speed when traveling in planing mode, i.e. ship is being pulled by the kites (knots) | 29 | 21 | this is a first estimate, based on typical to high speeds for combustion engine powered similar-sized boats, to be verified, depending on kite size, wind along the route, boat's shape & length | |
| estimated percentage of planing cruise along the route of total route distance, i.e. minimum 20 knots wind (and appropriate direction) expected during that part of the route so that the planing speed from the line above is achieved by the kite's traction (as average speed) | 80,0% | 80,0% | to
be verified by evaluating wind speed/direction statistics of the North
Atlantic Ocean; the percentage will be higher for a US to Europe cruise than
for a Europe to US cruise; as a first guess, 80% for east-bound traffic and 65% for westbound traffic (difference due
to main wind directions) seem to be realistic figures for the 'planing
threshold wind speed' of 20 knots (5 Bft.) mentioned above (this applies to
an altitude of approx. 100 metres above the sea). Calculation is done for 80%. When using 65% instead, the voyage will take about 2 days longer. In case you are lucky and catch strong wind during 95% of the voyage, trip duration is 2 days less! |
|
| calculated 'planing-mode' voyage duration (hours) | 88,28 | 121,90 | ||
| calculated 'low-speed' mode voyage duration (hours) | 80,00 | 106,67 | ||
| calculated total voyage
duration day(s) hour(s) minute(s) |
7 | 9 | ||
| 0 | 12 | |||
| 17 | 34 | |||
red font indicates that values can be varied freely within in a certain range or still have to be verified, while figures in italics should be changed only within a small range to get meaningful results. Values are due to current technology, derived from various sources. All other values except 'General ship data' have been calculated (regular or bold font); their description is preceeded by 'calculated'. |
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| Please note: The clear distinction between sources of power * electric engines for 'low speed (displacement) mode' and * kites for 'high speed (planing) mode' was made for calculation purposes. When traveling at light winds in displacement mode, the electric engines driven propellers may of course be supported by kites, while solar cells charge the batteries. Taking this into account, total travel time will be less. |
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