Even docked, the water rushing under Falkor looks like a powerful river. One Broome local described it as the rhythmic cycle of the ocean breathing, but it seems like seriously heavy breathing to me. The tides here are unlike any I have ever seen; growing and falling over 10 meters as we prepare for the cruise. This makes loading and unloading the ship a difficult task. There is only a short time in which the cranes on Falkor can be used to transfer cargo from the jetty, so strict timelines of four to five hours have to be planned and followed.
Not just the moon
Most children are taught in primary school that the tides are caused by the moon’s gravitational pull. While the moon is a major factor, it is not the only one. The sun is also involved, using its gravity to pull on the oceans too. Here on Earth, these two aspects can factor heavily into the amount of movement in the seas. The geography of coastline sculpts the flow of seawater, but more importantly is the force created by the rotation of the earth itself. To see this effect, think of spinning and tilting a bowl full of water in your hands. While not a perfect metaphor, it helps reveal how the shape of a container and the container’s movement cause changes where water moves.
Looking at the tide tables, you can see some of the global differences in tide sizes. I was struck by the difference between my homebase port of Honolulu, Hawaii and Broome, NW Australia. NOAA’s tide chart shows Honolulu’s consistent, small tidal changes that sway between two meters. Broome on the other hand, is highly variable with five to ten meter swings. I guess we can just be thankful that we are not loading in the Bay of Fundy, which has the world’s largest tidal changes of up to sixteen meters.
Royal tides of Broome
“King Tides” are a non-scientific term used to describe the highest tides of the year. Although there are a few tides predicted to be a bit higher in the next month, there is no doubt that the massive movements of water taking place in Broome fall into a category worthy of royalty. To see for yourself, check out the video that shows footage from Falkor’s mobilization while docked in Broome’s port.
Do you notice the remarkable water turbulence created solely from the tides? No engine or ship movements are contributing to the water movement. Watch and listen as Lead Marine Technician Leighton Rolley describes the challenges of preparing Falkor during these extreme tides.
Luckily, we have a fantastic crew onboard, and have successfully mobilized for the Coordinated Robotics cruise.Falkor is now underway heading towards the Timor Sea, where the science team anticipates beginning robotic trials.