Kuroki Ship


49 knots / hour (90 km) Economical fast cargo ship

KurokiShip is a concept of an economical fast cargo ship. It is a hull shape of bow and stern with low resistance of water acquired “Japan Patent 6198232” and international applications “PCT / JP 2017/029448, WO 2018/051711”, and propulsion device for advancing the ship forward Has adopted a submerged water turbine with good energy efficiency (fuel economy). In addition, the lower part of the hull navigates in semi-submerged state, the ship does not shake due to the weight of the water, and it can navigate to the ECO safely and comfortably (less CO2 emissions due to good fuel efficiency per ton of cargo).

■Hull form
I will explain the shape of the hull. Cut the hole in the front and back direction of the rectangular parallelepiped, and make this water passage through this hole to flow the water in front of the bow to the stern. The upper part of the hull is a cargo room. There is a cockpit in front. In order to reduce air resistance, cover cargo room and cockpit (other, main machine, various equipment equipments, sailor’s cabin etc.) with skins and round the aft stern. The lower part of the hull is a space under the waterway, having a buoyancy volume sufficiently larger than the weight of the ship and the total of cargoes loaded, allowing the ship to float (with designing and building). Both sides of the hull connect upper and lower parts and support the upper part. The outside is the ship’s outer skin. The inside is the side wall of the water channel. There is also a staircase that goes down into the space under the waterway where the propulsion device is located.

■Propulsion device (wheel)
The propulsion device is a water mill that is aligned full of space in the space under the water channel. The tip feather portion protrudes from the bottom of the ship, sending water backward and the ship going forward. Change the direction of the ship by changing the rotation speed and direction of rotation of the left and right water wheels. Rotate the water wheel, brake suddenly on the ship, go backwards on the ship.

■Ship not shaken (staible)
Kuroki Ship has water on top of the waterway floor at the bottom of the hull, and the ship does not shake due to heavy water pushing down the waterway floor (furthermore air does not go around the bottom of the ship). While navigating, the wave rises and falls above the surface of the water flowing through the water channel, above the water surface that goes up and down is the air, it does not push the boat, so the ship does not shake.

KurokiShip is a hull shape and propulsion device, and has acquired “Japan Patent 6198232” and international applications “PCT / JP 2017/029448, WO 2018/051711”.


■Comparison table of ship form

Types of ship form high speed Fuel economy Rough seas Shaking Price of ship Loading capacity Number of voyages
Normal ship (mono hull) X
Hydrofoil X X X
Catamaran X
through hull ship (kurokiship)


■Comparison table of propulsion devices

Types of ship form Propulsion device Number efficiency high speed
Normal ship (mono hull) screw propeller 1or2 X
Hydrofoil water jet 2or4 X
Catamaran water jet 2or4 X
through hull ship (kurokiship) underwater whell 5-9


■Specific samples of Kuroki Ship

Speed Speed per second full length Overall width = width of water passage + width of both sides Height gauge = high waterway bottom + waterway street height Drainage = under water channel + both sides – water turbines
knot/h km/h m/s LOA B=Bww+Bgw total=underWW+upperWW displace=under+gunwale-wheel
knot/h km m m m m m3
49 90 25 80 34=2+30+2 17.6=6.3+11.3 8,258=7,526+1,526-780
68 126 35 84 31=2+27+2 12.6=3.8+8.8 4,627=4,001+896-270


Kuroki Ship determines the shape of the waterway floor according to the cruise speed (so that the acceleration applied to water becomes 1 G). If necessary drainage volume is insufficient (up to the amount of drainage required) Lengthen the total length.