A keen eye for hull form design

“Hull design is central to any new project”, he told MJ. Certainly, Mr Bonafoux has been involved in a couple of landmark designs that fit a very specific brief. For example, ultra-fine catamaran hull forms that have extremely low wash for environmentally sensitive areas.

“I have always looked on advanced hull form design as being key to our business”, he said. Having produced high performance hull designs for catamarans and SWATH’s, Mr Bonafoux explained that BMT Nigel Gee projects have included a new hybrid Semi-SWATH design, which combines a cat’s speed with a SWATH’s seakeeping. Furthermore, one project about to come off the slipway is the new XSS (Extreme Semi-Swathe) for wind farm operations, with the first vessel currently being built in the Netherlands.

Mr Bonafoux said, “This design has a very small water-plane area, reducing forces on the hull and providing improved seakeeping and ride comfort for passengers.” However, he added, offshore turbine crew transfer can still be an issue: “Existing transfer vessels push up on to the wind turbine foundation and the crew have to pick their moment and jump.”

With this thought in mind, a joint BMT Nigel Gee and Houlder project has resulted in an active hydraulic access ramp which automatically compensates for the pitch, roll and heave of the vessel. This opens up the window of operation to 2m significant wave height and, most importantly, improves the safety of transfer.

“In terms of exciting designs we had to design a high speed ferry that competes directly with air travel for an Argentinean project. It’s still the fastest passenger ferry,”

“We pushed the boat out, quite literally, on both the hydrodynamics and lightweight construction. We knew it had to be a first principle design as we couldn’t simply build it to class.”

The end result was a 45m, 300 passenger capacity ferry with four gas turbines powering two waterjets, giving a top speed in excess of 50 knots.

In a similar vein, the US Seafighter vessel was an 80m craft designed for 52 knots with 500 tons of deadweight. “It was the first vessel designed to the new US Naval Rules. It had to take two helipads so we developed specialised aluminium extrusion for the helideck structure to minimise weight. This was double skinned, and can survive the high helo dynamic load, although the plate is only 3mm thick, a tremendous project.”

However, says Mr Bonafoux, “The other thing that’s served us well is being able to do complete design from a blank page to detailed production, turnkey packages. Seeing something through means not just helping the yard gain a competitive advantage, but it also affects us. “We get insight from the guys on the shop floor during construction and see things right through to sea trials, it’s one of the most enjoyable parts of the job.”