Marine engine software specialist Stephan Bernhart from Kaltental-Blonhofen has made it his mission to breathe more power and torque into motor yachts since 2008. His company Yacht-Performance claims to be a pioneer in maritime software programming (software tuning). Sea-Help met the “performance designer”, as he likes to call himself, for an interview.
Thanks to the know-how he has gathered over the last 15 years and direct programming via the original control unit, Stephan Bernhart promises “up to 30 percent more power, up to 25 percent more torque and up to 20 percent fuel savings on motor yachts”. SeaHelp editor Matt Müncheberg spoke to Managing Director Stephan Bernhart about how this works. Müncheberg spoke to Managing Director Stephan Bernhart from Yacht-Performance.
How did you come to tune motor yachts?
Stephan Bernhart: I’ve been working on the driving performance of yachts from 35 feet upwards since 2008. I came to it like the virgin to the child. I used to optimize cars, and then one of my customers had a boat. I actually trained as an office administrator, but tuning has always been my hobby and my passion. In 2004, I bought into a Munich-based chip tuning company.
How exactly does the optimization work?
Programming the map is a bit like MS DOS Zero One. For example, I can use it to reprogram values: more power, more boost pressure, more injection and so on.
So in principle it’s about chip tuning?
Yes, it’s just technically a completely different ball game to cartuning. In the automotive sector, we have a six-, seven- or eight-speed gearbox, drive at 130 km/h, have traffic jams, city traffic and the engine is always at 20-50 percent of the possible speed range.
The boat engine is a so-called continuous runner, which means that in the best case scenario, the customer warms up the engine before heading out onto the lake, a river or the sea, and then runs it at 80-100 percent speed because he simply needs the corresponding speed if he wants to get from A to B with the boat. Gliding is simply the best and most economical way to sail, but you need power and optimally tuned propellers for this. I have customers who have never filled up their yacht with gas because they could no longer planing…
The yachts start planing between 30 and 40 km/h, at which point economical sailing is also possible, i.e. sailing at a relatively high speed with relatively low consumption.
We’re only talking about optimizing turbodiesels here?
Yes, because the turbocharger is the most effective component for helping a diesel engine achieve higher performance (compared to a naturally aspirated diesel). Ultimately, the trick is to perfectly match the turbocharger to the engine map – whether under load or at high intake temperatures – my aim is to ensure that this always works perfectly.
And: I always try to achieve the best possible result with as little power as possible. Example: I have a racing driver among my customers who wanted maximum power output. He wanted me to “pack in everything I could”.
The customer had a D4-300 engine (Volvo Penta, 300 hp, 3.7 l displacement, four-cylinder; editor’s note), installed on a 38-foot yacht. I normally optimize the D4-300 engine to 350 hp, but in this case I got it to around 400 hp, which is really sporty. There is also a “Sport Plus” optimization, but the difference between a “normal” optimization and a “Sport Plus” optimization is so marginal that it’s often not worth the risk.
What does the fun cost the owner?
It starts at between 6,000 and 12,000 euros for the pair of engines. Then there are my travel costs, I travel to France, Croatia, Poland, Italy, the North Sea and the Baltic Sea, I’m on location all over Europe. In November 2023, I was also able to work for German customers in the USA.
I now work with regular cooperation partners. This includes certain yacht dealers who look after their customers’ boats. The dealers are happy about my work because they can see that fuel consumption is going down and the customer can sail more lively if he wants to. Shipyards are now also among my partners.
Can you say that your work helps boat owners to make their boats more economical and yet faster?
Exactly, more economical, if we assume cruise speed. Of course, if the customer wants to put the lever on the table, then you can’t help them in terms of consumption, which is often up to ten percent higher.
But when it comes to saving fuel, it’s all about cruising speed. I currently have a Fjord48 customer with three IPS 600s who now saves 30 liters per hour at cruise speed after optimization. At full speed, however, he now needs 285 liters per hour instead of 255.
If the customer drives a lot (and he does, the boat is on the island of Rügen and he often drives over to Poland) at cruising speed, then he can really save. It would also have been possible to fit larger propellers – for even more speed at reduced engine speeds.
An older customer with a Fairline 54 with the Volvo D9-575 engine with shaft drive, who has his boat moored in Lignano and often sails it in Croatia, had the propellers on his boat adapted by me for 12,000 euros.
In combination with my adapted engine management system, he can turn the engines to full power despite the larger propellers, which means an extra ten km/h top speed and noticeably more powerful acceleration, as the larger propeller can convert more torque in the water.
Its cruising speed – with the original propellers – was always around 22 knots, with 9.4 l/sm consumption. At the same speed, it now reaches 24.4 knots – with only 8.2 l/sm consumption.
If you extrapolate this to 5,000 nautical miles, then this results in a saving of 6,000 liters, which adds up to 10,200 euros less to spend on diesel fuel. The customer also told me that his mirror is now no longer black.
Why are the optimizations not offered by the dealers or the shipyards themselves?
What I do involves a lot of time, and neither the manufacturer nor the shipyard has time. In addition – if we take three identical motor yachts, for example – each one is different due to the different weight (due to more or less equipment and accessories) and different engines.
One customer prefers 2 x 400 hp, the next 2 x 500 hp, one swears by IPS drives, another prefers a shaft drive and so on.
And there is the issue of warranty: of course the factory warranty expires with new engines. Nobody wants to make a concession. Therefore, every potential customer has to decide for themselves whether to wait until the warranty period has expired – or not. But I can say that to date, none of my customers have had any damage as a result of the optimization. On the contrary. I do something good for the engine – and for the customer.
Example: a customer cruises with his 54-foot yacht at 22.5 kt and 82-85 percent engine load – after my work, the engine load is only 70 – 72 percent under otherwise identical conditions.
If I have a yacht that has a negative weight/power ratio, then these engines are already struggling, have a higher exhaust gas temperature, wear out faster and consume more fuel. That’s where I come in.
Do you offer your customers a guarantee of success?
Yes, you could say that. I live from my consistently positive references. These include some large yachts such as a Princess 72 with 2 x Caterpillar C32 V12 engines, each with 1,600 hp, and a 74-foot Van der Valk Continental 2 with three IPS 800 engines. The largest ship I have optimized so far was a Pershing 8X with 2 x MTU 2,450 hp each. In the end, all customers were extremely satisfied.
So-called chip tuning is well known in the car scene – and doesn’t have the best reputation. The reason for the negative connotation of the term are car tuners, who in the past have pushed engines beyond their limits – with the result of rapid wear or even the complete destruction of the engines… The difference with yacht engine tuning lies in my individual programming – that guarantees my quality – but actually tuning works the same way with cars as with yachts: the performance of the engines is subsequently increased by a targeted change to the control parameters set at the factory.
The difference with yacht tuning by Yacht-Performance, however, is that I look at what makes sense without overstressing the technology. I achieve this by giving the engines more power by exploiting the thermodynamic and mechanical reserves of the engine a little more through so-called “map optimization”. This is where my wealth of experience and know-how from the last 15 years comes into play.
Further information: yacht-performance.com
