Key Suppliers Halyard at Fairline

Close co-operation between British motorcruiser builder Fairline and its long-standing exhaust systems supplier Halyard has not only cut engine noise to well below new RCD limits, but also produced boat design, manufacturing and cost-saving gains. Bob Greenwood reports.

A Halyard Inset Silencer and wet-exhaust system installed on a Targa 47 under construction at Fairline’s main plant at Oundle. This approach can reduce engine noise by a substantial 4dB(A)-5dB(A) below the RCD’s 78dB(A) limit, which comes into full force from January 2007 for twin-engined motorcruisers such as this.

Fairline engineer Lee Archer stands beside the Inset Silencer on a Targa 47.

An engine exhaust riser elbow minimises the risk of water ingress into the engine.

This aft compartment on this Targa 47 provides a neat and unobtrusive housing for this dual-chamber silencer.

The riser is supported from below to help reduce vibration.

When installed on this new Phantom 47, now being prototyped at Fairline for a spring 2007 launch, the Halyard Inset Silencer will take up about this amount of space. With the system occupying just 25 per cent of the volume filled by a dual-chamber system, the aft cabin will be able to use the full width of the hull.

Halyard’s new Inset Silencer can be tuned to take out unwanted resonances at certain engine speeds. Although it won’t make for a super-quiet boat, it will bring noise levels to within RCD limits.

Adam Greenwood, Fairline design director (left) and Matthew Taylor, purchasing and supply-chain director. With space and cost savings and RCD compliance, the Inset Silencer “ticks every box”, says Greenwood.

Only five years ago a prospective motorcruiser owner might have cocked an ear over the transom of the boat he was interested in buying and noticed that the engine noise was a little louder than preferred. “Now a boatbuilder is just as likely to point out that there’s, say, an 800Hz spike at a certain rev range and that could come uncomfortably close to breaching the RCD sound emissions limits,” says James Grazebrook, managing director of Salisbury, UK-based boat-noise and attenuation specialist Halyard. “Knowledge about noise emissions has moved on hugely.”
This shift in awareness regarding sound emissions has been due to EU Recreational Craft Directive amendments that become mandatory within the European Union from the beginning of next year. These will impose strict limits on the amount of noise that boats are permitted to make when passing within 25m of an observer. The RCD sets a maximum of 75dB(A) for a boat with a single inboard engine and 78dB(A) for twin-engine installations.
For builders of sailboats and smaller powerboats with engines with integral exhausts — such as outboards, where it’s the engine manufacturer that’s held responsible for engine noise — compliance is generally no problem. But for builders of inboard boats of 45ft (13.7m) and above the onus to comply switches back to them. For these boats, even when they are built in series, engine-exhaust systems virtually have to be custom made.
“Each exhaust is quite a different animal,” James Grazebrook explains. “Aside from internal layout options within a given model, owners can also specify from a list of engine options, so there can be wide variety of exhaust permutations. And over and above RCD requirements, owners can also actually choose how quiet they want their boats to be.”
“Keeping below the RCD limits, and even going as low as 73dB(A)-74dB(A) for twin-engine motorcruisers, is comfortably achievable,” says Grazebrook. “And although some customers may want to be significantly below RCD requirements, others will not be so concerned. Boatbuilders can choose between meeting the noise limit, perhaps on a sports model, and targeting a significantly lower noise level, perhaps for a flybridge model where the emphasis may be more on comfort.”
Halyard itself led work to find ways to meet RCD noise requirements. In association with Institute of Sound and Vibration Research (ISVR) at Southampton the company ran the EU SoundBoat project. “This programme has given the whole industry a greater understanding of boat noise issues, particularly in the 50ft (15m) and above sector,” says Grazebrook. “Very few boats have problems below 50ft, but as time goes by we will be able to match consistently the silencer design to the problem frequencies in an engine’s noise transmission. A number of engine manufacturers have been very helpful in giving us access to noise characteristics.”

One motorboat builder that was not satisfied with the noise and vibration characteristics of a recently introduced sub-50ft (15m) model, and that has worked closely with Halyard to implement a new solution to solve the model’s problems, is UK builder Fairline. The boat in question was the Targa 47, a hardtop express cruiser that was launched at the 2004 Genoa International Boat Show. While generally quiet and refined in operation, the model was found to develop an unwelcome resonance at a certain engine speed. This minor fault, which is not uncommon on hardtop boats of this type, was corrected with a new design of exhaust system developed jointly by Halyard, the ISVR and Fairline. The research resulted in a silencer system that not only tuned out an annoying vibration, but also provided substantial space utilisation and cost benefits.

Like Halyard’s more usual dual-chamber exhaust noise suppression system, this new Inset Silencer uses injected water to reduce noise. But it does so without the large GRP silencer drums in the pipework that normally take up a significant amount of engine-room space and that can also limit cabin space.

The new Inset Silencer takes up only around 25 per cent of the volume of the traditional dual-chamber silencer and uses a carefully sized small chamber around the main gas and water flow area, says James Grazebrook. “Both the chamber size and the flow to the additional chamber are crucial,” he says. “The work we have done with the ISVR has helped us achieve a degree of noise reduction that will generally get a twin-engine installation within the required 78dB(A) limit.”
The Inset Silencer was developed to offer a smaller, lower-cost alternative to dual-chamber systems. “It was never expected to achieve magical silence,” says Grazebrook. “But now, having quietly played with the Inset Silencer for two years, we are looking at the next generation of the system to tune it to different engine and boat types.”

For exceptionally low noise levels, sometimes 5dB(A) or even 8dB(A) below the RCD requirements, he sees the dual-chamber silencer as the way forward, especially the latest versions with underwater outlets. The dual-chamber silencer in a tuneable wet-exhaust system can produce noise reductions of up to 80 per cent and with minimal back-pressure, while exhaust gases are diverted below the waterline.

Also, because the exhaust exits below the waterline, ducting can also be positioned low, so as not to intrude into cabin spaces. A further plus is the absence of the ‘station wagon’ effect, where grease stains form on the transom.
Fairline’s new Squadron 66 motoryacht, premiered at the 2005 Southampton International Boat show in September, embodies this latest exhaust system technology. “In early-to-mid 2004 we started looking seriously at exhaust and noise emissions,” says Fairline’s design director Adam Greenwood, while outlining his company’s progress in engine-noise suppression. “As a boatbuilder we’re now looking at the finer details as awareness of noise and emission issues increases.”

While the boatbuilder also makes use of materials such as 3M Thinsulate to insulate bulkheads, floors, hulls and internal liners in order to reduce resonance, exhaust- noise attenuation has been a key element in its quest to build quieter boats. “In the development of the Squadron 66 we worked closely with Halyard to develop a simplified exhaust system using existing components,” says Adam Greenwood. “We weren’t trying to be too clever. We simply wanted to put the silencer in-line with the through-hull exhaust, and then ‘back-engineer’ this into our Squadron 74 (Fairline’s flagship model).”

The results have been impressive. The main objectives behind the exercise — to minimise noise and vibration and to keep component costs down through reduced complexity — have both been amply achieved. “We obtained 66dB(A)-74dB(A) against the RCD maximum of 78dB(A),” Greenwood claims. “And we’ve reduced component costs by £7,000 (E10,500) per installation. It was also simpler to fit and there was a huge price advantage. It ticks every box as far as we are concerned.”

On the supply side, it’s Matthew Taylor, purchasing and supply-chain director, who is in charge. Since he joined Fairline last year from Cummins Newage, he has been reviewing logistics in this area. His aim is to reduce in the space of a year the 400 line suppliers on Fairline’s books to fewer but core companies that supply systems rather than sundry items and small volumes of materials. “We’re rationalising suppliers into systems suppliers,” he told EB. “We buy things at a higher level of assembly, so it saves us assembly time.”

While Taylor reckons that 150 or so could be trimmed, there’s no ultimate target number owing to the diverse range of items that go into Fairlines. “However, our objective is to establish a group of key suppliers that make our business theirs,” he says.

Halyard, which has worked for Fairline almost since the exhaust systems manufacturer started trading 24 years ago, belongs to the inner circle of Fairline certified suppliers. “We involve these suppliers right from the concept stage of any new boat model, so that they can design for manufacture, give added value and minimise any compromises that often need to be made with key boat systems,” says Adam Greenwood.

The process continues with the attendance by senior engineering and technical personnel at key stages during the development of new models right through to signing off systems for functionality by the supplier at the final test stage. “It’s very intensive,” says Greenwood, “with anything up to six months’ testing on all prototypes.”

Once a new model goes into production, it is then down to suppliers to deliver components and systems — minus packaging is Fairline’s preference — to fit in with the boatbuilder’s production schedules. “Our direction is ‘just-in-time’, although we’re not there yet,” says Matthew Taylor. “Joinery, for example, will not happen overnight. There’s no JIT timetable, but some suppliers have already started. A lot see it as an opportunity to differentiate themselves.”
Taylor promises “a lot of change next year” in this area, with more internet exchange and new applications to enable raw data, notably CAD images, on to the Fairline website.

Halyard is one supplier that is more prepared for Fairline’s new supply-side disciplines than most. Last year it committed itself to ‘lean manufacturing’ and is at present working its way through a checklist, which, according to Grazebrook, should see it “reach the Holy Grail of 80 per cent of achievement of lean objectives — with an inter-relationship between what we design and what we manufacture”.

For 2006, on the manufacturing side, Halyard is aiming to implement a wide range of measures to increase its own efficiencies and supply capabilities. These include
growing the use of 3D CAD design; building half of its exhaust systems for production boatbuilders to a ‘ready date’ for line-side delivery two days before installation in the hull; shortening its delivery lead times to 10 days; and, ultimately, reducing its own manufacturing costs.
“People tend to think that regulations are restricting and are all about disadvantage,” says Adam Greenwood. “But as far as we are concerned they encourage smarter thinking and are often a benefit to the market. We treat such things as opportunities!”

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