Marine gearbox proves its worth

Edited by the Engineeringtalk editorial team Jul 22, 2003

Preproduction testing of Newage Transmissions' recently announced StepDrive marine gearbox has confirmed the unit's reliability under the most arduous operating conditions.

Preproduction testing of Newage Transmissions' recently announced StepDrive marine gearbox has not only confirmed the unit's reliability under the most arduous operating conditions, but revealed that it will offer Volvo Penta Duoprop owners even greater performance benefits than originally expected.

StepDrive is an automatic two-speed transmission that can be retrofitted to Volvo Penta Duoprop 290 drive legs.

It is installed entirely within the centre section of the Duoprop unit and has been designed specifically for use with naturally aspirated engines such as Volvo Penta AD31 and 41 series - as well as supercharged units up to the KAD 44.

As part of Newage's rigorous test procedures, a Sunseeker Portofina 31 powered by twin Volvo Penta AD41 engines has been equipped with two StepDrive units and subjected to extensive sea-trials on the UK South Coast.

Throughout the programme, the company's previously claimed 25% increase in acceleration and ability to get onto the plane 20% faster than before have been consistently exceeded.

"In a series of timed runs, the vessel's 0-20 knot time has been brought down from 24 to 14s - a massive 40% improvement in acceleration", says Newage's Marine Sales Manager, Jamie Pratt.

"By providing an additional reduction ratio of around 25%, StepDrive not only boosts performance, but also reduces creep speed, emissions and noise when manoeuvring in busy marinas or restricted waterways.

"It has enabled us to replace the Sunseeker's original A6 props with A7s.

As a result, the benefits of improved boat handling and fuel economy are now combined with an even higher top speed".

"In order to assess the benefits across a wide range of applications, we also intend to trial StepDrive units with a variety of other pleasure craft hulls and engine combinations during the final stages of the product's development programme", he adds.

Since the beginning of the year, exhaustive power rig testing has also been continuing at Newage's Coventry headquarters.

According to Marine Project Manager, Paul Barton: "We have almost completed an exhaustive 1500 hour programme, which has been designed to simulate years of normal pleasure craft operation".

"To date, the testing has been remarkably trouble-free, with no mechanical failures in the driveline components at all.

I am therefore confident that the StepDrive will more than uphold the reputation established by our PRM marine transmissions for extreme in-service reliability and durability".

"We are not just targeting the pleasure craft market and indeed, I can confirm that we are already evaluating a number of commercial applications where StepDrive's benefits can be utilised to the full", he adds.

Trials of StepDrive gearboxes are due to be completed in September, with availability of production units - through a network of Volvo Penta approved installation centres - scheduled for the fourth quarter of the year.

However, Newage is so confident in its new product's capabilities that the company is already inviting potential customers to experience StepDrive's benefits for themselves, by arranging an onboard demonstration on the Sunseeker 31 test boat.