How to Design a Sailing Ship for the 21st Century?
canopic jug writes:
LowTech Magazine has an article on designing large-scale sail powered ships with the most recent engineering. Even with all the recent advancements, it will be difficult to acheive carbon neutral transporation.
These two ships - one under construction and one in the design phase - have the potential to make sail cargo a lot more economical than it is today. That's because they have a much larger cargo capacity than the sailing ships currently in operation. As a ship becomes longer, her cargo capacity increases more than proportionally.
The 46 metre long Ceiba is powered by 580 m2 of sails and carries 250 tonnes of cargo. The 60 metre long EcoClipper500 is powered by almost 1,000 m2 of sails and takes 500 tonnes of cargo. For comparison, the Tres Hombres is not that much shorter at 32 metres, but she takes only 40 tonnes of cargo - twelve times less than the EcoClipper500. A larger ship is also faster and saves labour. The Tres Hombres requires a crew of seven, while the EcoClipper500 only has a slightly larger crew of twelve.
[...] The EcoClipper500 has no diesel engine on board, which is a second reason to focus on this ship. Obviously, a sailing ship without an engine cannot proceed her voyage when there's no wind. This is easily solved in the old-fashioned way: the EcoClipper500 stays where she is until the wind returns. A ship without an engine also needs tug boats - which usually burn fossil fuels - to get in and out of ports. For the EcoClipper500, these tug services account for 0.3 g/tkm of the total carbon footprint of 2 g/tkm.
Without a diesel engine, the ship also needs to generate all energy for use on board from local energy sources, and this is the hard part. Renewable energy is intermittent and has low power density compared to fossil fuels, meaning that more space is needed to generate a given amount of power - which is more problematic at sea than it is on land.
Paint and electricity consumption also figure into the calculation.
Read more of this story at SoylentNews.