Superyacht, helicopter platform design solutions

 Location of the heliport can be driven by aesthetics - with the potential dangers of turbulence and movement not always considered 

I met one in 1985 with the 36.8-meter Buckpasser motor yacht built at Hitachi-Zosen for an American sportsman. It was one of the first yachts to boast a fully functional helicopter landing zone. Ogden Phipps used the helicopter for his hunting and fishing activities around the world also towing his Merritt sports fishing boat.

Even today, Buckpasser remains one of the smallest yachts to incorporate a helideck. The reason is simple: heli-platforms take a lot of planning, space and money. The sacrifices are not often worth it for a smaller yacht where the compromises are proportionally stronger. With a larger yacht, costs and trade-offs become more manageable as part of the overall project.

The approach
There are two approaches to a helicopter landing aboard yachts. The first, the "touch-and-go" touchdown or emergency landing, is a great place to land the helicopter, never stop, and take off as soon as its passengers or goods are embarked or disembarked. There are no established standards for such operations, with details the rulers have worked on a case-by-case basis between the designers, builders and relevant regulators of civil aviation, the classification society , the flag State and the insurer. Note that this is only for non-commercial operation.

The touch-and-go has no real reference, says David Nelson, senior aviation consultant at Helidecks Training Solutions, a yacht heliport design office and an MCA-accredited training facility. "However, the owner of a" private heliport "would be stupid not to have the equivalence with the standards. Most classification societies have their own fire-fighting and life-saving equipment to meet the requirements of the ISM.

None of this indicates that each uncertified heliport is dangerous. Many abide by the spirit and requirements of the trade regulations, but lack certain dimensions in centimeters. Such is the case with Feadship Lady Christine, built for a certified helicopter pilot.

The second approach, called fully certified or certified in the trade, is much more comprehensive. For red-flagged superyachts or its equivalent, especially those in the charter or who intend to charter, the main regulations governing their design, construction, and operation can be found in Grand Commercial Code Maritime and Coastguard Yacht Agency (LY3) Annex 6.

Greg Marshall designer designer of the 75m yacht places the helicopter pad on the main deck
 Greg Marshall designer 75m yacht designer places the helicopter pad on the main deck 

Acceptable compromise
Between "touch-and-go" and "fully compliant" is a gray area of ​​compromise for private use situations that some designers and builders are reluctant to discuss.

"International aviation regulations require that all helicopters engaged in commercial air transport operate with a certified heliport or in this case helideck, which must have been built according to defined standards and characteristics," says Nelson. "The owner of a private yacht and helicopter does not need to build his helideck to the same standards or obtain certification, if the use is exclusively non-commercial. This has a limitation, however. The owner would not be able to use an external helicopter service to arrive at his private helideck.

Even if a Red Ensign yacht is fully compliant with Annex 6 and approved by the flag State, its crew, helicopter and pilot are subject to port state requirements. Even Annex 6 states, "The landing area will be limited to helicopters under the conditions agreed by the Aviation Inspection Board." This refers to weather conditions, but is more widely applicable. . To navigate such a labyrinth of requirements is size. Many owners and captains delegate this task to specialized private agencies that ensure everything is in order before arrival.

Lack of space
"The obstacle-free length is equal to 1.25 times the length between the tail rotor and the main rotor shaft.This said the distance is 13 meters, then you need 16 meters without obstacles in length. This is a large area, especially on yachts under 70 meters, "says Ronno Schouten, chief designer of De Voogt Naval Architects.

Some builders have developed intelligent methods to process permissions and ground plan effects (airflow). Folding rails are used in many cases just like a removable safety net and recessed lighting. In other cases, the structure is transformed during helicopter operations. For example, the hardtop on the 50-meter Westport Tango hinges up to 90 degrees to create additional clearance, and block the interaction of airflow between the helicopter's rotor and the satcom masts and domes of the yacht .

134m Fincantieri superyacht Serene has a helicopter hangar and two heliports, one of which turns into a swimming pool
 134m Fincantieri superyacht Serene has a helicopter hangar and two heliports, one of which turns into a swimming pool 

Location, location, location
"The helideck's plate is much more likely to be driven by the aesthetics of the yacht's design rather than the potential dangers of turbulence and motion," says Nelson. With a helideck on the upper deck he is more likely to ride on the main deck, for example.

"The owner's choice between landing on the front or rear deck has big implications on design," says Schouten. A buffer on the foredeck has less impact on design and allows landing when the rear decks are used by the customers. However, landing at this location is usually not possible when the boat is moving.

"The turbulence generated by the superstructure plus it is large and more annoying also where there are angular corners and large polyhedral faces," says Nelson. There are ways to design features that minimize the disruption of airflow - just look at a modern car. If we are involved with a yacht at the design stage, we always encourage the ideas and use of fluid dynamics (CFD) to avoid problems with turbulence.

The next thing on the air offer horizon will likely be tilting aircraft and a UK design firm has already started a yacht design that will land an AW609 aircraft. "For something like a tilting rotor, which can be turbulence-sensitive, CFD analysis is a must," says Nelson. That said it is still the future, however, that certification for the AW609 civilian is scheduled for 2017. Of course, for an owner who desires a plane that can cruise at 300 mph for 852 miles, carry nine passengers and to pose on its platform, three years is a minimum of design time.

A helicopter takes off from Feadship Lady Christine superyacht
 A helicopter takes off from Feadship Lady Christine superyacht 

Weight considerations:
All heliports, both certified and touch-and-go are designed for a collision load that is the maximum weight of 2.5 times the helicopter. Normally bridges are designed only for sea and human loading, and occasionally for point loads to tie down, but when helicopter operations are added, they must be reinforced, with an additional structure sometimes necessary for the helicopter. 'helideck to the keel. This adds weight, which increases the overall displacement, which continually affects speed and fuel consumption. Except on larger yachts, helidecks are usually at or near the top of the yacht. This extra weight, at such a distance above the keel, will also have a significant negative effect on the boat's stability, so added beam and fine stabilization may be necessary to compensate.

Do you want one?
"It is extremely important for ship designers and shipbuilders to obtain aviation advice as early as possible to avoid difficulties or costly changes in the future." The primary goal is to establish from the start what the owner wants to use his helicopter because this entails the design and equipment, "says Nelson. "For example, the owner does not want to do the transits of the ocean with his helicopter, which can mean a hangar is needed? Does he need to fly at night, which requires a lighting plan? How much flight is intended and do require the helicopter on board fuel or maintenance capability? "

All builders and designers indicate that most yachts over 60 meters build in a minimum of touch and-go capability, for emergency evacuation if not regular use. The Nelson database includes 66 yachts over 60 meters with helidecks, nine of which are fully certified. Another option for some owners is touch-and-go ability aboard the yacht itself with MCA Annex 6 compliant landing and stowage aboard a shadow vessel.

The choice of configuration of the helideck, are limited by the size of the boat and the scope of the imagination of the designer to meet the regulatory requirements.

 This article was published in Megayachts April 2014
Photos and illustrations by Marc Paris; Mark O'Connell