Life Onboard the KOSHI 51

Fastest in Its Class. Without Compromise.

The KOSHI 51 is the fastest boat in the world in its category, built without compromise for those who refuse to waste time and demand the very best from every moment at sea. It is extreme engineering turned into a lifestyle: sharp lines, advanced technologies, and a lightweight build that makes every mile pure adrenaline.

Every detail has been designed to deliver absolute performance without sacrificing essential comfort. At the bow, sunbeds and seating provide space for open-air relaxation and conviviality. Below deck, an elegant cabin with a double bed and dedicated storage combines practicality and luxury in a minimalist, functional environment.

With the KOSHI 51 you never waste time: you arrive first, live more, and turn every journey into an unforgettable thrill.

Overall Length (Incl.Engine)
17.2 m/ 51ft
Beam
3.46m / 11ft 35in
Dry Weight
(excl. Engine)
2100 kg / 4630 lbs
Lightship weight
(include Engines)
4600 kg / 10100 lbs
Full load
(full fuel - ready to run)
6200 kg / 13600 lbs
Fuel Capacity
1550 ltr. / 410 gal.(US)
Construction
Full Carbon Fibre / KOSHI Patented Technology
Passangers
P:8
Top Speed
+100 MPH
MAX Power Engines
MERCURY 4 X 500R 2000HP
Accomodation / Berth
2+1 persons
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  • ANCHOR

  • FWD SEATS

  • FOLDABLE TABLE

  • SUNBED

  • THRUSTERFWD
    STORAGE SPACE UNDER BED

  • BED FOR 2 PEOPLE

  • OWNERS CABIN

  • BATHROOM

  • CABIN ENTRANCE

  • DRIVER / PASSAGERS

  • WETBAR

  • SINK
    GYROSCOPE (optional)

  • AFT SEATS

  • FUEL FILLER

  • TECHNICAL COMPARTMENT

  • AFT SUNBED

  • X4 MERCURY 500R ENGINE

For those who value time above all.

Koshi Marine was born with a clear mission: to redefine the limits of the sea. We do not build boats for everyone, but for those who consider time the most precious asset. For those who know that every second not fully lived is a second forever lost.
Our flagship model, the Koshi 51, embodies this philosophy. Entirely crafted in carbon fiber with cutting-edge technology, it is not just a boat: it is an engineering masterpiece designed to transform speed into freedom. The Koshi 51 does not follow records, it rewrites them.

Built for One.

Every Koshi is created for those who refuse to blend into the crowd. Every line, every detail is shaped to reflect a personal and unrepeatable vision. We do not mass-produce; we create unique experiences, tailored for those who recognize the true value of exclusivity.

Time waits for no one. Neither do we.

Luxury is not only about comfort or design, true luxury is time itself. The Koshi 51 was born to ensure none of it is wasted. Arrive earlier, live more, never wait: this is what it means to dominate the sea with a Koshi.

Philosophy remains unchanged

extreme engineering, carbon, patented technology, and an unshakable promise, to offer a select few the privilege of bending time to their will.
Koshi Marine does not follow. It does not imitate. It does not chase.
Koshi Marine redefines.

About Us


Koshi Marine was founded with a clear purpose: to set a benchmark in the marine industry with every single project.
We do not build ordinary boats , every Koshi is designed to become a reference point in yachting.
With over 20 years of experience in producing high-end carbon fiber components for the world’s most prestigious supercars, Koshi Group created Koshi Marine, bringing the same industrial know-how to the sea.
From this expertise, we developed a patented technology that combines carbon fiber and epoxy resins, delivering yachts that are lighter, stronger, faster, yet uncompromising in comfort and safety.
Koshi Marine means true exclusivity. We do not pursue mass production or shortcuts: every yacht is built as a unique masterpiece, shaped around its owner, without compromises and without imitation.