ACG's VTM® (Variable Temperature Moulding) carbon epoxy prepregs have helped British marine glazing manufacturer Trend Marine Products of Catfield, Norfolk, UK, to develop a line of light and strong sliding sunroofs that have opened up new design possibilities for a growing number of production boatbuilders.
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The demand for open-top yachting has been in great demand in recent years. However, boat owners want the security of being able to close the roof quickly when the weather takes a turn for the worse while still taking maximum advantage of whatever natural light is available. As the fashion for open express cruisers continues to demand ever-larger production/semi-production boats, the requirement for larger sunroofs has placed increasing technical demands on boatbuilders and their suppliers. |
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Initially, for Trend, the main problem was to produce an unsupported, gently curved structure that would carry a large sheet of heavy safety or laminated glass. However, the structure had to be light enough so that it didn't raise the boat's centre of gravity, while also being rigid and slim enough to slide away neatly out of sight when the roof was open. Moreover, it had to do all of this without encroaching on the available headroom. |
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Working hand-in-hand, ACG and Trend developed a solution using one of ACG's custom-engineered VTM carbon fibre and epoxy prepregs, one that ticked all of the above boxes. With this solution in hand, the company now produces opening roofs of up to 3x3m using ACG's VTM carbon fibre laminate with glazed panels.
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This project had proved to be so successful that, what started four years ago as a small sideline to the Trend's main business of producing windscreens, windows, portlights and glazed doors for powercruisers, has become an important new manufacturing stream. |
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Robin Thatcher, Trend's Technical and Sales Director, says, "Our sunroof business has been gathering pace - almost to a drum beat. Sunroofs are the fastest-growing part of our business now. In units, we were making about 150 a year, but with our increased capability on the bespoke carbon fibre side, we are now looking at producing 200 or 300 roofs a year. This business now accounts for between 5 to 10 per cent of our turnover." Furthermore, Mr. Thatcher states, "Sales of all Trend products are now approaching £20 million a year". On the sunroof side, the lengthening list of customers includes all of the UK's largest powerboat builders as well as Spain's Rodman and France's Bénéteau group, where it now supplies roofs for five boat lines. |
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More recently, motoryacht builders in North America have also become customers for Trend's sunroofs. These include one major US production boatbuilder that is due to launch a new powercruiser model later this year. This will have a large sheer glazed, double curved and tinted sunroof mounted on a light carbon composite grid.
The single most important factor in Trend's success with sunroofs has been its ability to mould relatively large, yet light and strong structures in carbon fibre composite. Here, Mr. Thatcher acknowledges that the composites engineering expertise of ACG played an essential role in this advancement. Mr. Thatcher states, "Trend wouldn't be making sunroofs in carbon fibre if it wasn't for ACG."
Four years ago, Trend was building sunroofs for a leading European powercruiser builder using a carbon prepreg from another supplier. However, because things were not going to plan and the laminate was not performing as required, ACG was asked to help.
Initially, ACG felt that the original product was over-designed so new tooling was manufactured. This included a plug incorporating an air channel to remove air bubbles from the laminate. The basic design was also readdressed to lighten the product and produce a flex-free arch.
This news item is based on an article by Robert Greenwod and first published in the European Boatbuilder June/July 2007. | 
