YETI footprint breakthrough

8 april 2021

Promising developments have been seen recently with a measurement tool designed to allow the entire superyacht industry to objectively assess the environmental credentials of existing yachts and new concepts. Initiated by Feadship’s Bram Jongepier, the Yacht Environmental Transparency Index (YETI) has been taken to the next level over the past two years under the auspices of the Water Revolution. The ultimate goal of stimulating technologies which reduce energy demand and enhance system efficiency is now much closer. "I could never have imagined that my brainwave at three in the morning one night in November 2018 could have led us to this stage. We now have a very powerful group of yacht building colleagues, yards, naval architects and knowledge institutes collaborating on the YETI. And the achievements have been impressive", says Bram Jongepier, senior design specialist at Feadship De Voogt Naval Architects.

Compare and contrast

The original challenge that Bram identified and Feadship initially set out to solve was the lack of comparison models which exist to assess how eco-friendly superyachts are. Yachts sail at a variety of speeds so are not like commercial vessels. Nor are they switched off when moored so any comparison with car rating systems is invalid. While yachts provide accommodation for guests, they do not stay at the same location all the time so cannot be compared to hotel buildings either. Clearly something unique to the superyacht world is required… And the prize will be big. Being able to evaluate the ecological impact of a yacht should enable improvements to be made by taking a life-cycle approach. Examples include enhanced hydrodynamics (flow optimisation, propeller efficiency, displacement), systems (efficient machinery, heat recovery, insulation), materials (recycling, sustainable sourcing), and the local environment (underwater noise, zero discharge emission capture).

Speaking the same language

Recognising that a yacht index would only be truly effective when adopted by the superyacht sector at large, Feadship was pleased to hand the YETI baton over to the Water Revolution Foundation in March 2019. A great deal has been achieved over the past two years within this joint-industry approach, with a focus on finding clear definitions for the operational profile of yachts and the energy they consume. Data from some 130 yachts has been analysed to develop a calculation method for these benchmarking operations. A first working model is now up and running that calculates emissions and, as such, environmental impact, expressing them in so-called ecopoints. The current calculations consider, amongst others, the effects of part-load efficiencies of engines, shore power consumption, battery banks, sail power, exhaust treatment and waste heat recovery. The next step is to find a common denominator to make a comparison between yachts. A verifiable functional unit of luxury is needed so that the same experience can be provided to clients by using less resources. Efforts made to reduce that resource consumption will then be reflected in the ultimate YETI score.

Get involved

Lots more trials will be carried out over the coming months with a wide range of designs in order that this score will reflect the actual efficiency. While the index is still under development, peer-reviewing by the wider yachting community is welcome. Such a proactive approach will accelerate sustainability in yachting and future-proof our collective business. Contact the Water Revolution Foundation at if you would like to become involved in this vital work.