How smart masts could revolutionise yacht ventilation

The new mast ducting system from Carbo-Link is one of those ideas that many will say ‘Now, why we didn’t think of that?’ Basically, air expands when heated. This makes it lighter, causing it to rise, and as it does so, cooler air is drawn in to replace it. This is the basic principle of the sea breeze in coastal areas. The land heats up during the day, pulling a cool, refreshing breeze in from the sea, and this principle has been adapted for a fossil-free yacht.

For the team building SY Project Zero, the aim is to run the entire vessel off renewables and to make every electrical system as efficient as possible. Heating, Ventilation and Air Conditioning (HVAC) is one of the most consistently power-hungry systems on board, but the two huge carbon masts contained part of the answer.

The team realised that if both masts were black, they would quickly heat up in the sun. The air inside would expand and rise, and if there were vents at the top and bottom, the hot air could escape. Cool air would be drawn in from the bottom to replace it. Find a way to pull this air through the yacht first, and you have a low energy cooling system.

Built by Vitters, the Project Zero ketch is 68.8m long and requires two bespoke masts, the tallest being 70m. Bob van Someren, a physicist working with Foundation Zero, calculated that if a large duct was run up the inside of both masts, they would act like big chimneys. The oval profile of the masts would present a large surface area to the sun, with estimates they could generate between 5 to 10kW of air displacement between them, depending on the weather. As a large electric fan would use 1 to 1.5kw, the masts would be able to create enough air movement to meet the projects low energy goals.

Collaboration with Carbo-link

Whilst everything looked good in theory, there remained some questions about the realisation. Would a large duct running the full length of each one, and the necessary vents tops and bottom, have any negative impacts on performance, and maybe even safety? As 70m carbon masts aren’t exactly available off the shelf, the Project Zero team approached Carbo-Link, a Swiss firm with a long track record in cutting edge composite fabrication. The company has already worked with marine OEMs like Rondal, Baltic Yachts and Royal Huisman, and is active in other sectors such as construction and aviation. Everything is designed and built in house, giving the company full control over all aspects of the project. The ducted mast was the type of challenge they relish, and the task fell to Edoardo Volpe, their mast development engineer. Volpe had to ensure that the ventilation duct, something that had never been done before, would not affect the masts’ ability to take the huge amounts of force from the intertia of a seaway, yet remain flexible enough to ensure optimum sailing performance.

“The integration of the of the ventilation duct does not change the principles of mast design,” he said. “However, there are still some issues as it drastically influences the structural design choices.”

Using a whole suite of 3D modelling and a holistic approach to design and construction, Carbo-Link successfully completed the task.

Just how successful the concept is will be revealed in a series of sea trails later this year. Foundation Zero says that the most exciting element is the fresh approach this could deliver for the marine industry. “Cooling and energy balance is a huge issue for boats of all sizes,” their report concludes. “This novel way of using the mast for ventilation is something a whole range of vessels can take inspiration from.”