Designers Converge on Proa Sail Power Concept

A design for a zero emissions cargo ship has been unveiled that again highlights the potential of a proa for reducing emissions.

The Fair Winds Trading Company is currently in the research and design stage for a sail cargo ship based on the ancient proa; a multi hull cargo sailing ship of the South Pacific. 

The company plans to initially transport goods between its sustainable development project in West Africa and Argyll, Scotland. The long-term vision is to assist small island developing states and coastal communities in the least developed countries to acquire their own ships and establish their own trade routes.

“Our aim is, not only to achieve a zero negative impact method of sea transport, but also to demonstrate to commercial shipping and the market that this is not only do-able but desirable,” said Madadh MacLaine, founder and CEO of Fair Winds Trading Company.

The PraoCargo’s most significant design aspects are its load/size ratio, stability and multi access capabilities. Due to its structure, the 60m long vessel has a shallow loaded draught of four to six meters depending on rudder position, minimum heeling and can maneuver under sail in shallow waters. The vessel is designed with a maximum speed of 25 knots, and an average speed of 13 knots under sail, backed up with an electric motor drive system.

Alain Guillard, the naval architect and designer of the vessel has recently built a 12-meter model of the intended ship on which he is currently transporting gravel to test her functionality in the Gulf de Morbihan, France.

TankerProa

The design shares the proa concept with a design developed in the U.S. Inventor Dr Frank J. Berté has patented TankerProa (to be used for tankers and bulk carrier vessels) and the CargoProa (to be used for container ships).

The TankerProa can temporarily transform a tanker vessel into a pure sail powered vessel for greater than 95 percent of its trans-ocean voyage along the trade wind routes, without the use of any diesel fuel. The TankerProa stays a short distance offshore near the originating port or the destination port. It couples or decouples from the vessel to be propelled at these locations and never enters the port area.  

“TankerProa will have masts on the order of 400 feet in height and will have about four times the sail area of the PraoCargo ship. In addition the height of the sails will be able to reach an altitude where the wind speed is almost double that at the ocean surface,” says Berté.

TankerProa has the ability to move its masts to insure maximum wind thrust for downwind sailing as well as broad reach sailing. “TankerProa generates the full amount of power to control the sails, rudder and dagger boards from wind, wave and solar energy storage required to propel the vessel, even while it is at anchor, because of the balanced design for all components,” he says.

For tanker vessels, TankerProa can propel them when fully loaded, as well as when emptied. For empty tanker vessels, the use of the TankerProa eliminates the requirement for ballast water (and the required clean up before this water is dumped), since the TankerProa stabilizes the vessel with its outrigger while significantly reducing the total vessel tonnage to be propelled when empty (~ two million pounds). 

When the empty tanker vessel is in the origin port preparing to go to the new destination port it can take on ballast water in about 45 minutes before leaving from the port to go to the nearby TankerProa location offshore, it can dump ballast water from this port once coupled to the TankerProa.  This de-ballasting process will only take about 1.5 hours. 

The close proximity of the TankerProa decoupling/coupling locations, where it takes on ballast water or performs the de-ballasting, relative to the origin or destination port location,  means that there are no invasive species being introduced, in either origin or  destination port proximities. 

A 10 meter prototype has been successfully tested on the Massachusetts Maritime (20,000 pound) Model Tanker Vessel, converting this vessel into a pure sail powered vessel. TankerProa provides for a low cost conversion for existing vessels, and Berté is currently planning fabrication of a full scale TankerProa.