Ocean Race Teams face the wild waves of the Southern Ocean
Photo by Julien Champolion (Available at www.theoceanrace.com/en/news/13606_Team-Holcim-PRB-remain-perfect-after-record-breaking-run)
The Ocean Race is one of the toughest professional sailing events in the world. Leg 3 of the race, from Cape Town to Itajaí (Brazil), started on 26 February 2023. This leg takes the fleet on a monstrous 23,613-kilometre Southern Ocean passage, three quarters of the way around the bottom of the world.
The teams are currently navigating near Campbell Island, Aotearoa New Zealand’s southernmost island (check out the race tracker). The Southern Ocean is a unique ocean basin, the engine room for generating swell waves that then propagate throughout the planet. Persistent mid-latitude storms combined with a lack of landmass create large fetches and strong winds, ideal conditions for generating large waves, producing challenging crossing sea states.
As a multi-disciplinary group of oceanographers, experienced mariners and technical experts passionate about the ocean, the MetOcean team is following closely the Ocean Race. MetOcean physical oceanographer Simon Weppe says that in terms of performance, this leg is particularly interesting as the effects of waves on boat’s “polars” (i.e. the sailing speed as a function of wind speed, direction and sail) is still not well included in the routing that sailing teams use to optimize their route.
“For example, some percentage of speed degradation or enhancement can be considered (e.g. +10% speed if waves are following courses, -10% if waves are head on), but the approach remains relatively simple compared to the very finely tuned “wind polars” all boats have. This is even more important now that the boats can foil above the water, thus significantly increasing their speed, but only when the sea states allow.”
MetOcean wind and wave forecast at Campbell Island (52.511S, 168.311E), issued Mar 16, 2023 10:04 AM NZDT (MetOceanView).
The Southern Ocean is the world’s least studied ocean, despite occupying 22% of the global ocean area and its known role in the Earth's climate system. Together with the New Zealand Defence Force, MetOcean Solutions have produced a state-of-the-art wave atlas of the Southern Ocean. The detailed understanding of the characteristics of wave climate is required to test and inform future designs of vessels that will be tasked with operating in the highly energetic Southern Ocean. The Southern Ocean Wave Atlas included a collaborative measurement campaign between MetOcean Solutions and Defence Technology Agency (DTA), and a large modelling effort. One of the wave buoys of this project, moored at Campbell Island, recorded a massive 23.8 m wave in 2018. The racing boats also act as vessel of opportunity and collect oceanographic data as they sail through the remote Southern Ocean waters (https://www.theoceanrace.com/en/racing-with-purpose/science), providing a unique opportunity to help fill a valuable gap in scientific knowledge.
Sub-Antarctic waters are difficult to work in, conquering the southernmost waters of the planet has long been a badge of honour for the world’s best sailors. The MetOcean team have also joined the race by sailing virtually in the Virtual Regatta Offshore game (www.virtualregatta.com/en/offshore-game/?openrace&573-3). The team experiences sailing in these challenging conditions from the safety of their computer screen, but the game also allows us to follow live the metocean conditions the real sailors are facing.
We wish all the racing teams good luck!