Yanmar and Bubbles

Simon Millar bought his first whale-watching vessel at the age of 22 – a brave step for a young man only a few years into the commercial boating game.

Move forward to 2020 and Simon added yet another catamaran to his fleet, (an ex-reef tour boat from Far North Queensland), and re-fitted it to work as a 100-passenger whale watching and tour vessel.

MV Bubbles is a 2013-built SeaSpeed design and handles her duties well. You may have seen her well ahead of the spectator fleet outside Sydney Harbour in the 2021 Sydney to Hobart yacht race, handling less than ideal conditions very well indeed for a power cat.

Simon has learnt a few things about running vessels in his time skippering, and like every experienced commercial operator he knows that reliability is king of the sea.

“I had new Yanmars (6HYM-WET) fitted in April last year and we’ve put around 500 hours on the engines to date,” Simon says.

MV Bubbles was running European-branded engines with rated outputs of around 552kW. The new Yanmars fitted are rated at 515kW (700mhp) @ 2,200rpm but according to Simon “we are getting very similar performance”.

The Yanmar refit was an easy decision for Simon – he is a big fan of the 6HYM-WET’s mechanical operation and simplicity whilst being well-aware of Yanmar’s unbeatable reputation for reliability.

“That’s what we’re after more than anything,” says Simon, “we really need the reliability and longevity out of the engines, and that’s what Yanmars seem to give.”

 Taking a look at the work MV Bubbles has to deliver in and out of whale watching season, you understand why reliability, (and extended service intervals, up to 500 hours between services), offered by the 6HYM-WET platform is so important.

“During the whale watching season, we would be running four trips a day,” Simon explains.

“That involves longer running times when the whales are doing their northern migration – it would not be unusual for the engines to be running at least 14 hours a day.”

 Each whale-watching trip usually involves a firm cruising run out to sea, (MV Bubbles cruises easily at 17knots with her new Yanmars), mostly idling and low-speed movement whilst observing the magnificent sea mammals, then often a higher-revs run back to port to meet schedule.

“Outside of whale watching season, we run tours and special event charters,” Simon said, “and many of those tours will see us covering at least 30 to 40 nautical miles, so the engines have their work cut out for them.”

A key success in the Yanmar refit has been no loss of performance for MV Bubbles despite a slight reduction in horsepower. This is no doubt helped by the excellent torque-rise characteristics of the 6HYM-WET engine.

 Take a closer look at the full re-fit of MV Bubbles and you start to understand just how “torquey” these Yanmars are. With new running gear right through, MV Bubbles went from a higher-horsepower engine with 1.74:1 ratio gearboxes to the Yanmars with ZF325A gearbox reductions of 2.037:1.

Long-renowned for their ability to deliver outstanding torque across their power range, the Yanmars are also a frugal engine. “We’ve got similar performance out of the vessel but an improvement in fuel consumption,” Simon said.

“Fully loaded we’ll do our 17knot cruise speed for around 110 litres per hour (combined).”

MV Bubbles will still get motivated in excess of 23knots with a full load and recent sea trials proved a very respectable 26knots at WOT with less weight onboard.

With sea trial figures like that as proof, it’s easy to understand why the 6HYM Yanmar is the power of choice for so many commercial operators. The 6 in-line, 13.7 litre turbocharged engine will deliver its power and torque happily in a variety of applications.

In fact, you’re as likely to find one of these Yanmars doing the hard slog in a tug boat or lower-speed fishing vessel as in a high-speed catamaran like MV Bubbles. Such is the versatility of this well-proven, purpose-built marine engine. No doubt MV Bubbles will be leaving plenty of bubbles behind her for years to come as Simon and her entertain many thousands of happy passengers.