Volvo Penta: Drive for Wakesurfing
Wakesurfing is the real domain of the new Volvo Penta Forward Drives, which the company recently presented at the Miami International Boatshow and for which it was promptly awarded an innovation prize. It is a Z-drive with forward facing propellers, similar to those of the Pod-Drives. The system, allegedly developed in less than a year, combines the ideas of the IPS and Duoprops into a “pulling” propulsion system that places the propellers about 50 cm further forward under the hull.
This makes it unlikely that a wakesurfer will fall into the propeller and get seriously injured, especially if the boat is equipped with a floating platform. In Miami, the shipyards presented Bryant, Four Winns and Cobalt boats with the new propulsion system, while others are still in the testing phase.
Wakesurfing, i.e. riding the stern wave of a slow motorboat without a tow rope, is a sport that has been practiced for generations. But in recent years there has been something of a renaissance, which has also been supported by the manufacturers of inboard towboats and waveboards. Shipyards that had boats with Z-drive in their program and could jump onto the wakeboarding train (with tow rope) with the tower screwed on were left out of wakesurfing, simply because the proximity of the athlete to propulsion and propeller would have been too dangerous. The Forward Drive should solve this problem.You can check the article for further information at Best Bowrider Boats of 2018 by Boats.com.
The lower drive unit is slightly smaller than an IPS1 and is bolted directly to a duoprop centre section. Unlike an inboard engine, the Forward Drive has trim options that can be used for a larger wake. The exhaust fumes are also emitted under water, allowing the boarders to breathe a little better air behind the boat. This engine is offered with engines between 200 and 430 hp, with Volvo believing that the upper hp regions (300-430) should be preferred. New K-series counter-rotating propellers have also been specially developed and Volvo states that the Forward Drive will cost about 10 percent more than the conventional Duoprop Sterndrive.
Pros and Cons
The most noticeable disadvantage that has been noticed so far is that this drive cannot be folded up as far as a normal Z-drive. At maximum angle of attack the propellers are still about 30 cm lower than the keel of the boat. Driving onto a sandy beach or operating in extremely shallow water should become more difficult. It might also need a modified trailer on which the boat with the stern is slightly higher and which has a special recess for the drive. Volvo says that the Forward Drive has no advantages or disadvantages in terms of performance and that fuel consumption, speed and acceleration are comparable to the Duoprop. The Forward Drive offers more thrust and control because the propellers are not disturbed by exhaust gas turbulence.
We were able to test a prototype of the drive on a 23-foot runabout with some waterballast and normal payload. A competent wakesurfer rode on the stern wave without any effort while the loaded boat was on its way with about 12 knots. Lighter loading was like a Z-drive, but with a striking difference: The thrust seems to be further forward in the curves, so that the boat felt more like an inboarder with tight radii.
Actually you could, if you wanted, drive it on the edges around the corner, like a jet boat, without any trim settings, because the propellers stay deep in the water and thus far away from the wake. If this is still a Spanish village, you can admire a short wakesurfing presentation behind a Four Winns TS 222, which is already equipped with the new propulsion.
You will have to see how the different shipyards use the Forward Drive and who think that Wakesurfing is reason enough to construct a new Runabout. In Miami, Four Winns showed its TS 222 with the Forward Drive, a runabout with a new hull and details that, according to the company, were specially developed for wakesurfing.
Bryant has successfully installed the Forward Drive in the 233X towboat and is already working on new models with special hull shapes for wakesurfing. Cobalt says they are satisfied with the performance of the Forward Drive in the 24 SD WSS and plan to offer it as an option for the time being.