Let’s harness the wind better! Let’s kite sail.
Kite Proa 2022
My goal for 2022 is to build another kite sailing boat my Prototype Nr. 2 and test it, first coastal then for long-distance and offshore sailing. After I will provide more detailed information on what worked and how well. Also, I will release my building plans for my kite sail proas once they are more prooven.
Why a kite sailing proa?
If the aerofoil – the sail and mast are fixed to the boat they create particular momentum and they limit the apparent wind speed to the same as on the hull. This is what has limited boat designers for a few thousand years. But with materials like Dyneema and kite textiles, a designer is free to change parameters and rethink how to harness the wind better.
A proa is a well-proven sailing boat concept from the Pacific nations with great speed potential. By design, the proa does not rely on a keel or rudder. Which makes it less vulnerable at high speed to a collision with partly floating or submerged objects. Sailing a proa with a kite system changes the economics and safety of the vessel significantly! There is no rudder to build, to pay for, or to break. There is no keel requiring extra local stiffness in the hull. No keel to run aground, to pay for, to break loose, or to sink the boat with its ballast. There is no Mast, then it can’t break, no expensive rigging is required, no critical fittings to break which are inaccessible or out of sight out of mind in sea conditions. All these savings in focus, time, or money can be used for building a bigger, simpler kite proa. Further, the proa seems to me to be the most economical for a long-distance ocean voyager, if you consider a very narrow hull to have a fast oceangoing boat. One might think of a catamaran, with its raft-like stability in waves but if you think of building two 10m of hulls you are building 20m of the hull, or if you build 15m of a proa main hull and a small narrow 5m outrigger. Considering the basic hull speed formula the 15m proa should be faster than a 10m catamaran. Considering this it would be more economical to build a proa. My aim is in total contrast to the majority of designers. While most try to fit as much hotel-room space into a hull as short as possible, to save on parking fees. I try to build the hull as long as possible while reducing the cost and externalities per length, to gain travel speed, comfort, and safety.
There are more benefits to a proa. The shallow draft makes it very versatile near the coast and enables beaching, which partly combats the length problem in marinas. The large flat deck provides space for handling kites or just to enjoy sailing life and all space can be kept unshaded for solar. Further, the outrigger provides a low to the waterline space to excess the sea, while underway or on anchor.
To clarify some potential questions for those unaware of the proa concept. A proa changes course by changing the sail pressure point and not by moving a rudder. This is comparable to sailing a Sloop (on certain courses) by only changing the sail trim and keeping the rudder fixed and neutral to change course – but not many modern cruisers make use of this. To achieve the change of the sail pressure point on a proa with a kite is technically easy by leading or attaching the kite lines to a point on a rail. By moving this point the course can be adapted. Further, there is another major difference with proas to most other sailing vessels. A proa doesn’t tack and doesn’t jibe. A proa shunts. Shunting is changing the direction of travel by reversing. This is achieved by moving the sail pressure point towards the middle and further to the other side. A proa is backward forwards symmetrical. On one tack one end of the hull is in front on the other tack the other end. For my kite sailing proa design, I choose the wind and weather always to be coming from the side where the outrigger is. On a beam reach course, the wind would pass over the outrigger first, then over the main hull the lines and the kite.
Kites and kite rigging
When speaking of kites most people might think of kite surfing kites or of paragliding aerofoils. There is much more out there. I aim to try a wide variety of kites and airfoils to harness the wind. Further, I plan a few different kite rigging and line systems. I will try to keep them as mechanical, passive, and simple as possible for the beginning. The kite rigging seems to be the major field of innovation and essential for safe and smooth long-distance sailing. Unlike hull and kite shapes and designs, there seems nothing of use out there. Only a few other kite sailing projects have some concepts they are working on. My kite rigging will comprise of a rail system to change the pressure point and a kite line system. The kite line system will have multiple lines which can be adjusted relative to each other, to enable kite steering at any height of the kite. Further, it will have overload protection. I also plan to start and recover the kites directly from the kite boat, without water contact. Details on this I will release in late 2022.