Feature 4 | MEGA YACHTS Size remains an issue
Trends in the design and construction of yachts over 100m are explored by Burness Corlett - Tree Quays.*
develop the arrangement and profile to fit to the owner’s requirements. Exemplary was a recent Burness Corlett Tee Quays (BCTQ) project ‘Motor Yacht A’, the exterior and interior concepts of which were designed by Phillipe Starck. Consultant naval architects and marine
T
engineers such as BCTQ are then brought in to refine the yacht designer’s concept into a workable design. Quite oſten the designer’s vision does not
start out as a feasible structural design, for instance glazing extending throughout the sheer strake, novel superstructure designs or large openings in the main deck for trays for low sill doors. Working these design features into
a feasible structural design requires understanding of what the designer is trying to achieve and a thorough understanding of the global structural issues involved. Trough BCTQ’s work in this area of
yacht design we have noted an increase in the number of yachts being constructed that are over 100m. We currently have two in build and one about to be signed. Te benefit of these larger yachts is that
they offer the opportunity of fitting more owner and guest accommodation, along with more space for tenders and water toys, and by virtue of the greater distance from the noise and vibration sources, they also provide a quieter yacht. Additionally, the larger yacht provides a more impressive status symbol. However, there are constraints placed
upon design as yacht sizes increase. Owners, for example, will still want to be able to enter small, pleasant ports and marinas and will not want to be alongside
*For more information, contact Jonathan Strachan, principal consultant naval architect, Burness Corlett - Tree Quays, E-Mail
jonathan.strachan@
bctq.com
The Naval Architect July/August 2009
he 100+m yacht market is a custom yachts market of one off designs initiated by yacht designers who
Motor Yacht A – Built by ThyssenKrupp Marine Systems at HDW in Kiel.
in larger commercial ports. Draughts are, therefore, limited. From a powering perspective it is clearly
better to install the biggest propeller possible. However, as this is constrained by draught and the requirement to have reasonable clearance from the propeller to the hull, the logical conclusion is that highly loaded propellers should be installed. However, this increases pressure pulses and can increase noise and vibration. Another factor is that, traditionally,
the maximum number of guests for commercially operated yachts was 12. As yachts get bigger, there is a tendency to end up with space for more than 12 guests, and this means the yacht has to be certified as a passengership. Tis passenger certification has an impact on the damage stability, life saving apparatus, escapes and fire protection, and therefore has to be carefully considered and discussed at an early design stage between the yard, owner’s team, class and flag, in order to ensure all implications are dealt with. For many years the Maritime and
Coastguard Agency’s Large Yacht Code LY2 has been the definitive set of regulations for design and build of motor and sailing yachts. However, it has an upper limit of 3000gt. As such yachts of over approximately 85m loa have to apply the appropriate IMO regulations. In general,
this results in a choice between applying SOLAS for a cargo ship or a passenger ship depending on the number of guests when the yacht is being used commercially. Te Cayman Island Shipping Registry is
currently developing a new code for yachts with between 13 and 36 passengers. Until these regulations are issued a number of matters will still need to be clarified on a case by case basis for each individual design; these decisions effect the lifesaving provision, damage stability, structural fire protection, escapes and material selection and fire load calculations. Tese issues are discussed in detail in the paper “Super and Mega yachts - Regulatory Requirements” presented by BCTQ and Lloyds Register LR at the Design, Construction and Operation of Super Yacht and Mega Yachts Conference in April 2009. SOLAS states that all cargo ships over
85m be fitted with lifeboats, whereas all passengerships 500gt and above including those on short international voyages are required to be fitted with lifeboats. Tese regulations require lifeboats to be
fitted for yachts over 3000gt whether they are cargo or passengerships. However Flag authorities have agreed to allow lifeboats to be replaced with davit launched liferaſts on several 100m+ projects as long as a two compartment damage standard is applied. Tis is entirely discretionary and the exact
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