Dangers of hitting whales

The 2023 Brisbane Hamilton Island Yacht Race got underway on August 4. While it proved to be a fast downwind ride, severe collisions with whales forced at least two crews out of the race, led to multiple injuries, and caused serious damage requiring, in one case, months of repairs.

For the crew of No Limit, a Reichel Pugh 63, their race came to a jarring end in the middle of the night off K’gari (Fraser Island) as the boat was hitting speeds of 20 knots (37km/h).

“It felt like a car crash,” recalls skipper and owner David Gotze. “We were fortunate that the collision occurred when relatively few people were on deck and not in a more vulnerable position.” Gotze details the physics involved: “At 20 knots in a sudden collision lasting 0.1 seconds, an unrestrained occupant would experience a force of roughly 10G, which is enough to cause severe internal injuries or death.

“For a 75kg adult, the kinetic energy at that speed is approximately 4000kJ, meaning the adult would feel a force equivalent to 10 times their body weight.”

While there were no major injuries, there were plenty of minor fractures and bruises among the crew.

“We also had one more minor collision, presumably with a whale near Mackay, bringing the total number of strikes to four in three northbound races,” Gotze added.

No Limit limped back to Mackay and was soon joined by another well-known race yacht and fellow competitor, Whisper owned by David Griffith.

“We were about 23 nautical miles [42.5km] off Rockhampton and at 8.30 in the morning, so it was perfect visibility,” Griffith recalls. “We were doing about 21 knots [38.9km/h] and not a whale to be seen. Then suddenly, bang, we stopped as if we’d run into a brick wall and people were flung everywhere.

“I was steering and was thrown against the wheel and damaged my ribs. Other crew members suffered a bloody head and concussion, broken bones, we almost lost someone overboard.”

Griffith and his crew later discovered that a large section of the keel had splintered. The hull and mast had to be checked with ultrasound and the rigging sent to Sri Lanka to get checked.

Considering an adult humpback whale measures up to 16m (52.5ft) and weighs around 40 tonnes, the incident prompted Griffith to research whale collisions with yachts and what might be done to avoid them.

“These humpbacks sleep a few metres underwater, so there’s absolutely nothing on the surface to indicate they’re there. It’s like hitting a reef,” he said.

Griffith began investigating devices known as ‘pingers’ that claim to deter whales by emitting signals of low frequency and variable volume. Pingers have been used for over a decade on fishing nets and ropes, and an Australian company, Future Oceans, is at the vanguard of the technology.

Just how effective they are is still under debate.

“The boat itself makes noise and for a whale the ocean is a loud place,” prominent whale researcher Dr Vanessa Pirotta explains. “There’s no magical tool that we have that’s going to help us avoid a collision … Both the whales and us are vulnerable to each other.”

The full version of this article ran in the Apr-May (Volume 41.2) issue of Club Marine Magazine. Find out how you can  subscribe to Australia’s leading marine lifestyle magazine here.