has many unusual calls from clients with specific questions on various propellers and propeller related equipment. A call last year however was slightly more unusual than most. The call was to help provide a propulsion solution for a 38m long Dutch barge, some 230 tonnes, that had to negotiate the difficult River Wye from its resting place of the last 25 years. The barge was fitted with a 1957 Volvo Engine 96hp@2200 rpm with a gear ratio 3:1. An additional challenge was to drive the vessel and bring it safely to a stop whilst a percentage of the propeller was out of the water.
The ‘Wye Invader’ needed to get down the River Wye from Hereford to a boat yard on the Severn River and is the largest vessel known to have navigated the many twists, turns and bridges along the way. The owner, Mr Frank Barton, explained about the vessel and how it was essential to maintain as much control over steerage as possible to Clements Managing Director Paul Williams. Two weeks later after some calculations and drawing on extensive experience a special propeller was provided which had a greater pitch than normal for such a vessel. The special propeller would help give very precise steerage with the limited water flow.
There were many bridges along the river, which had to be carefully negotiated especially in a river that has previously seen quite a lot of flooding, and was still quite high. In November the Wye Invader set off on its journey, often having to do almost a 3 point turn to negotiate some of the tightest parts of the river or tricky bridges. On a couple of occasions the cabin on top had to be removed to enable the barge to pass under bridges. After much effort and several stops along the way, the barge emerged at Chepstow and was free from the river and able to continue on to its destination.
Paul Williams stated, “The Wye Invader was certainly an unusual project for us, but as with all enquiries we took in to account the conditions the vessel would have to face and based on that we proposed a propeller to deal with the unusual circumstances of the propellers being partly out of the water. We produced an oversized propeller to cope which was almost twice the size we would have otherwise used. We also advised on some rudder modifications which helped to make the Wye Invader steer more easily.