Records are there to be broken, or so the saying goes. Some are just harder to achieve than others.

The world water speed record, set by Australian legend Ken Warby in October 1978 with his Spirit of Australia boat, still stands today. Over the past seven years, Ken’s son Dave has been testing his Spirit of Australia II boat, intending to break the 317.60 mph (511.11 km/h) record.

While Dave’s time period may seem long, at his recent outing in August 2025, he said they had only run the boat on the water for 26 days of testing. That puts it into perspective and highlights the difference between the eras.

“When dad ran his boat, he would go to Lake Macquarie, even Sydney, Lake Munmorah, just turn up and run his boat. We just can't do that,” said Dave Warby at Blowering Dam during his recent trial in August.

The team will return to Blowering Dam on November 8-9, 2025 for another weekend of testing.

Each year, they make adjustments and return for more testing. The boat handling has experienced changes that often require a rethink of strategy and then more testing.

Their most recent alteration is a complete change of the boat’s underside. Dave commented that when they originally built the boat, it “was fairly flat to run better in rough water”.

“Now I think it was a bit sticky in the rear end, and it didn’t really penetrate the water that much. So this weekend (August 2025), we’ve got a new ski on it, everything under the boat now is an exact replica of Spirit of Australia.”

The team visited the Australian National Maritime Museum to measure the underside of Ken’s boat. “We've actually been allowed to go to the museum and measure it because Dad never recorded it. It was added late in the piece in 77, he never ran a ski under the boat.”

“So we are now tuning our wings to meet the new attitude of the boat that is sitting more down in the rear end. So we just need to get it to run level with the new attitude of the boat.”

Commenting on his August test runs, where Saturday was cancelled due to rough weather, “Probably not,” was Dave’s answer when asked if the Sunday morning session was productive.

In their first August run, they only ran at speeds of 180 miles per hour and then 220 mph, with Dave describing the water as very rough. “It is really white capping down the other end. That’s the problem, it can look good from the bay and it’s alright to do a run past for people who turn up to watch the boat, but out on the course when we need to go fast, it’s still quite rough.”

For their second run, they stayed within a zone where the water was more favourable and worked on fine-tuning the wing further, but obviously with a shorter run.

“We done a hell of a lot of research at NSW University and Newcastle University helping us do the maths on the boat as far as what drag ratios are and lift ratios. What works in numbers doesn’t necessarily work in theory. We need the boat to sit a little bit down in the back, it’s doing that now, but we need to get the wing level as well so then it’s not lifting the rear end, so it’s actually level.”

Dave said that as he accelerates, he can feel the boat changing, and in the early session in August, the rear end was vague, and he could feel it wagging in the back. “That last run was better, so we are making another adjustment on the tail plane.”

“That’s basically how Dad done his, but this is a physically heavier boat than his. We just have to see how it looks on the water and adjust it accordingly by how I think it feels and how it looks. When you drop the back of the boat, that also puts an angle of attack on the wing.”

Weather and Planning

Planning well in advance to book the water space at Blowering Dam and then relying on the weather has affected progress on several days over recent years.

“Yesterday was a complete shambles to run the boat,” was how Dave described the first day in August 2025.

“We’ve had 26 days of running this boat, and to think my father could run a lot easier. Nowadays, it’s just really hard to put a boat like this on water.”

Each time, the team must apply for permits, organise all safety procedures, extract as much feedback from the boat as possible, make adjustments, and then proceed to the next stage.

Dave said that in most trial runs, they’ve gained the knowledge they needed to either tinker with boat settings and test again. But not every weekend has gone according to plan.

But the team left the August weekend confident that they were now on the right path to greater speeds. All done with safety, one of their key mottos. The boat has the power to go well beyond the record speed, but safe boat handling is a priority.

“We are going to get it. I have no doubt we are going to get it, but we are going to get it safely,” said Dave Warby on achieving the record.