Carapace Yacht/Submarine, hybrid category Carapace Yacht/Submarine, hybrid category
The Carapace project by Elena Nappi explores the submarine/luxury yacht relationship, and studies its interrelationships with the aim of achieving one product, which is... Carapace Yacht/Submarine, hybrid category

The Carapace project by Elena Nappi explores the submarine/luxury yacht relationship, and studies its interrelationships with the aim of achieving one product, which is a hybrid in terms  of structure and shape

by Elena Nappi

This study is the result of my degree in Naval Architecture and it is intended as an investigative tool in the field of nautical experimentation. Carapace takes its name from part of the exoskeleton present in some animals, and in the design is represented by a sun canopy arrangement forming the superstructure.

CARAPACEThis boat represents a new class of mega yachts, and can adapt not only to the increasingly selective and changing requirements of customers, but also to changing outdoor conditions. Mega yachts are no longer just about champagne and bubbles, owners can now offer customers, friends and relatives new thrills in complete privacy and an underwater experience even in adverse weather conditions.

The design is the result of two important factors that have changed and are continuing to change the international arena. The first is represented by socio-political changes and the paranoia of individual celebrities regarding personal safety. The second concerns changes in sailing in the last 10 years and the search for increasingly larger boats to show off. The submarine/yacht concept aims to produce a hybrid that captures the features and performance of the original vessels – the beauty and comfort of a luxury yacht and the privacy of a submarine.

This research had already started in the boat design field, but only as an approximation and without a fully-fledged, explicit combination of both types of boat. Various companies such as u-Boat Worx, Triton Submarines LLC, Seamagine Hydrospace Corporation and Ocean Technologies are now selling private submarines, whose dimensions range from 8.5 to 225 metres.

CARAPACEThese designs include everything from official rooms through to recreational areas, such as spas and relaxation areas. My research is targeted at boats under 80 metres for practical, construction and logistics reasons. In the Carapace yacht/submarine design the combination between yacht and submarine is visible in the deck plans, with 3 deck levels and an upper deck, and a focus on interior living areas created also for passengers with physical limitations.

This research presented several difficulties because there are currently no similar products on the market, and also due to the confidentiality requirements boat builders must observe.

Carapace is designed for the private and public market. The public sector may require this facility when there is a requirement to arrange important meetings, or define agreements or negotiations in complete confidentiality. Private customers may commission this submarine for reasons of privacy, but it will mainly be to spend time with guests and relax, and enjoy completely new experiences not usually available on normal yachts.

The boat has a light aluminium superstructure that acts as a sunshade and shapes the main deck with its functional configuration, an external hull, and a strong internal body which, in addition to the boat structure, also supports underwater pressure, acquiring a spherical shape.

CARAPACEThe boat’s intermediate decks are set up with the tanks and service rooms on the third deck, in addition to the electric motor and main heat engines, the batteries used by the submarine when underwater, and the hydrogen tanks, ensuring enough space is left for inspections and maintenance.

The second deck has rooms for the crew, the galley and meeting rooms. The upper deck has the guest areas, including wellbeing facilities, VIP cabins and a day area. Outdoor areas have an open bar, sun terrace, helipad and living area. Contemporary materials such as resins were chosen to decorate bulkheads in various rooms, alongside more traditional materials such as timber in all its forms.


  • LOA: 78m
  • Beam: 14.1m
  • diving: 2643 t
  • ∆ surfacing: 2308,3 t
  • Draft: 6.5m
  • Maximum speed (diving):13 nodi//kn
  • Maximum speed (surfacing):16 nodi//kn
  • Main propulsion: Diesel elettrico + sistema a celle combustibili
  • Diesel Electric + Fuel cell system
  • Days underwater: 10
  • maximum deep: 300m
  • People on board: 11 (10+1 disabled)

Tesi di Laurea in Architettura Navale
Università degli studi di Roma “Sapienza”- Facoltà di Architettura
Candidata: Elena Nappi
Relatori: Prof.ssa Arch. Rosalba Belibani (Sapienza Università di Roma)
Prof. Arch. Giovanni Zuccon (Sapienza Università di Roma)
Prof. Ing. Sebastiano Caldarella (Università degli Studi di Napoli Federico II- Dipartimento di Ingegneria Navale).

(Carapace Yacht/Submarine, hybrid category – – May 2018)

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