Volvo Penta D6-440A Repower Noosa Cat 4100

What is the Volvo Penta D6-440A?
That would be a 440hp variant of the popular D6 engine marine engine.
The D6 is a 5.5L in-line six-cylinder turbo diesel with a cast iron block, double-overhead camshafts (DOHC), and common rail fuel injection. It can be had from 300 to 480 crank-horsepower. The D6 engine, together with the popular D4 is the only engine designed from the ground up solely for marine use, it is not found anywhere else in the Volvo Group range. It was released in the early 2000s as the replacement for the venerable KAD300.

How good is the Volvo Penta D6 engine?
By all accounts, it's great. It is very popular in commercial, enforcement and private usage with it seen in a lot of European motor yachts between 40 and 50 feet like the excellent Beneteau GT45. Locally, it is found standard in the Riviera 395 SUV and we’ve seen it in Police boats including the recently launched police vessels from renowned Brisbane builders Norman Wright and Sons.

What drive units work with the Volvo D6?
In the Noosa Cat seen here, the drives were Aquamatic DPI Sterndrives. You can also order the D6 with IPS Drives and for shaft drive. With the IPS, you should see the best fuel efficiency with the shaft drive a close second however, for easy installation and in most repowers, you’re likely to want the DPI for its layout and weight distribution.

Who can I talk to about repowering with a Volvo Penta D6?
If you are in Queensland or Papua New Guinea, it is Seamech. If you are looking from somewhere else, you can find retailers and support from Volvo Penta’s excellent website

Who is Seamech then and why use them?
Seamech are a bunch of boating enthusiasts that happen to not only retail and service Volvo Penta but also a range of other brands including Kohler generators. As the distributing Dealer for Volvo Penta in Queensland and Papua New Guinea, they manage the Volvo Penta Dealer network in these regions. Beyond that, they are also experts in planning builds and rebuilds.

How did the Repowered Noosacat perform with the Volvo Penta D6?
Pretty well. The engines ran smoothly, as you’d expect from a six-cylinder and in terms of fuel efficiency, they really impressed given the hefty 11,000kg catamaran they were pushing.
Sea Trials: Twin Volvo Penta D6-440A in a Noosa Cat 4100 Deluxe
We ran the Noosa Cat off in Mooloolaba Bay a couple of hours north of Brisbane. The conditions were not perfect with a rolling 1-1.5m swell and a 10-20kt on-shore breeze.
We ran side-on to the wind, both with and against the seas to get the average of two runs seen below.
On board, we had seven people, a half load of fuel (~1000L) and some supplies. We estimated a displacement of 11,000kg.
I suggest the best fast-cruise is in the region of 2250-2350rpm evident by the engines consuming a combined 40L/hr. If you were looking for maximum range, at idle or just above, offers nearly 2000Nm of range with ten per cent fuel in reserve.
Flat out we saw more than 36kts in one run with the average of the two runs 35.1kt, a massive step up on the previous best the boat ran of around 22kts.
Not only was the WOT speed impressive, but look at the fuel consumption and consider how they compare to one of the best-performing outboards in the supercharged, in-line six-cylinder Mercury Verado. For its power, the 350hp Verado is widely seen as one of the most fuel-efficient engines around running two on a significantly lighter Axopar 37 Suntop monohull and the Volvo’s were 30% more efficient.
Looking at efficiency comparison in lower RPM is futile as the hulls and conditions are so wildly different but at WOT, the Volvos and Mercs are doing their best to turn as much fuel as they can swallow into momentum and right there is a big reason inboards are still so popular in bigger hulls.

So how much does it cost to install a pair of Volvo Penta D6’s with DPI Drives?
The owner of this 4100 did almost everything himself (with lots of help from his best mates). This included pulling the boat onto the hard, craning the old engines and drives out, rebuilding the engine and DPI cradles and installing the D6s. The team also ran the easy-to-install wiring for the throttle and connected up the EVC to their existing MFD.

We did ask Seamech what the cost of the engines is and at the time of writing, a D6-440A, DPI combo was around $200,000. This includes everything you need to install and fire up an engine with gearbox seals, throttle, gauges, wiring harnesses, exhaust risers and more included.

Putting a wet finger to the sky and guessing the cost for a Volvo Penta Dealer to also install a D6 into your hull and you’re likely looking at somewhere between A$10,000 and A$30,000. Why the big range? If you need new bearers, stringers engine room exhausting can add a lot of labour and materials whereas a simple build might not - you really need to have Seamech take a look at your hull to get a firmer idea of the cost.