New Age....Kite Power & Slender Ships
I’ve come to a realization in this current age of escalating fuel prices, that there are two forms of pleasure yachts that are likely to survive the energy crunch, and even possibly flourish…the motorsailer
and the kite-assisted power vessel
There’s been much written about motorsailers, including my preference for the multihull form of that gender…basically a more easily driven hull for both the motor and sail power to act upon…greater range, more economy, better performance.
Now we come to a new era, and again it’s the ‘fringe’ sailing youngsters that show us another way…kite sailing. You may have witnessed some of this activity out on the bays and the lakes where the windsurfers use to play. Check out this ‘YouTube’ clip, “I Can Fly”
There is power in that wind to drive our vessels, and methods to extract it other than conventional vertical mast sailing rigs. Para-foil kites can produce very considerable power, and can be controlled in flight as the military discovered long ago. Now if we get those kites up into the better winds aloft, we can tap into that more consistent energy than exist at the sea level.
Two companies that have been quite active in the promotion of driving ships with kite power are:
At present the Skysails group appears the more advanced of the two, particularly when you consider their single-line tethering, and computer flying of the kite. They have an automated stowage and deployment scheme as well. These parafoil kites can even fly upwind to certain degrees. A review of the websites is quite interesting. But they are not the only game in town, there is a lot of military interest in precision flying kites as well; ie, Atair Aerospace
How might this kite business affect the yachting business? It goes back to idea of a motorsailer, or phrased differently, a ‘wind-assisted power vessel’. If we can optimize the economy of the power vessel, as the trawler concept seeks to accomplish, and then add ‘sail’ assistance, we have a recipe for a ‘future class of new trawlers’
that can be quite economical to operate, and have a great range. I believe this could be a very viable alternative yachtform for our new fuel future.
Humphrey’s yacht design is very big on this idea as well. Attached is their tentative proposal for a 40M SkySail MotorYacht. They’ve termed it a SkySail-supplimented MotorYacht, “The use of the word ‘supplemental’ is chosen carefully. While we expect this family of boats to be able to ‘sail’ efficiently under SkySail, we foresee that fundamentally the boats have to be very efficient and seakindly motoryachts, and in this respect the common denominator for efficiently under both forms of motive power is low hull resistance. Thus our work on this generic set has evolved towards slender body hulls that derive stability from wavepiercing outriggers….they are in effect trimaran derivatives, which will have long rang capability under engine, not to mention the ‘free’ miles under SkySail."
I have been following some of the ‘slender ship’ technology as it has cross-over potential with multihull technologies. For a few references, visit these websites, and see a few of the attachments I’ve provided. There is considerably more reference material available.
1) : Worlds Largest Powered Trimaran
2) White Rabbit tri (see also here)
3) Very Slender Vessel, VSV (see also here)
4) Cable & Wireless Trimaran
5) Catamaran Vessels
Lets not forget the catamaran hullform, they are in fact slender ships as well. As I wrote in a recent press release, “Our next design (coming soon) will be an adaptation of this new motorsailing catamaran design into a kite-assisted power cat. We will exclude the Dynarig sailing rig and substitute a SkySail kite rig. Then next will be an entirely new hull design making use of the kite-sail concept”
Back to those design concept drawings by Humphrey’s (attached PDF). LINK
I can fully imagine a scaled-down version of this tri-hull design, in the 65-70 foot range, with a wonderful rear ‘swim’ platform deck incorporating a sportfishing arrangement and/or a Scuba diving platform. Just inside could be a tender stowage as shown; or rather a complete diving & fish tackle facility. The tenders could then stow up on rear deck, or one forward, one aft.
The power would be a single main engine sized to develop the vessel’s desired top speed, and it could transmit this power by conventional shaft/prop arrangement, or with a azimuthing Volvo IPS dual prop unit, or via a retractable azimuthing Rim-Drive prop unit as I included on my latest dynarig motorsailer design.
1) Volvo IPS
2) Rim Drive
: Rim Drive
Supplementing this single main engine would be a single DC diesel/electric power unit to provide for:
1) Ships electrical requirements
2) Slow speed operation by electric (wing) motor belted to main prop shaft
3) Maneuvering thrusters as required depending upon azimuth capabilities of main prop.
The entire ship would be powered by only two engines, basically sized to provide
1) Full main diesel power, unimpeded by interceding diesel/electric conversion
2) Slow speed operation and ship’s systems via the smaller diesel/electric unit
3) ‘Twin power’ emergency backup as either engine can run all gear
This configuration more ideally meets the latest thinking for the new diesel/electric DC technologies onboard smaller vessels. Alternatively, two identical diesel/electric plants might be sized such that in combination they would supply the max power required of the vessel, and half power for lesser times.
Only two engines and no conventional sailing rig should make this a more affordable vessel, both in construction, in maintenance, and in operation. However the SkySail kite arrangement will probably more than offset the conventional sailing rig in cost. Possibly a less expensive alternative to this ‘brand name’, with less computerization could be found (no integrated weather/navigation features, etc). Light-weight construction would be desirable but not necessary. Third world hull construction materials are a possibility.
I’ll call it a KiteSail Motorsailer for now.
Your comments on these ideas are welcomed.
Brian Eiland RunningTideYachts.com
* I must include a disclaimer that many ‘superyachts’ will also survive, as there will always be some people with unlimited funds to do whatever strikes their fancy regardless of price of construction and operating expenses.