A catamaran lifting apparatus is disclosed for lifting objects in a marine environment. The apparatus includes first and second vessels that are spaced apart during use. A first frame spans between the vessels. A second frame spans between the vessels. The frames are spaced apart and connected to the vessels in a configuration that spaces the vessels apart. The first frame connects to the first vessel with a universal joint and to the second vessel with a hinged connection. The second frame connects to the second vessel with a universal joint and to the first vessel with a hinged or pinned connection. Each of the frames provides a space under the frame and in between the barges that enables a package to be lifted and/or a marine vessel to be positioned in between the barges and under the frames. In this fashion, an object that has been salvaged from the seabed can be placed upon the marine vessel that is positioned in between the barges and under the frames.

This invention relates to a pipe-like appendage for a sharp-edged pontoon of an offshore vessel, a pontoon structure comprising the pipe-like appendage and a method of converting a sharp-edged pontoon into a pontoon comprising at least one rounded-edge.

Disclosed is a mount for attaching objects, like cameras and bindings to the surfaces of a surfboard. Further disclosed is related methods of fabricating or retrofitting a surfboard with said mount. The more specific details of the disclosed mount and related methods are described in connection with the figures.

A system and a method for carrying out stability tests on a vessel are provided. In order to assess the stability of the vessel, it is of utmost importance to know the position of its center of gravity, and in particular of its center of gravity in the vertical direction. The system and method disclosed herein provide stability tests that include determining the position of the center of gravity of a vessel ashore, i.e., without the vessel having to be put in the water. Stability tests can thus be carried out in the same shed in which the vessel is being built, without the vessel having to be transported to the nearest water basin. In addition, the stability tests can be carried out at any stage of the process of construction and set-up of the vessel, and may also possibly be repeated several times at subsequent stages of the process.

A method of estimating a frictional resistance of a ship bottom coating film, the method including measuring any one of Rz (maximum height roughness), Rc (mean height of roughness profile elements), Ra (arithmetic mean roughness), Rq (root mean square roughness) and RZJIS (ten-point mean roughness) as a roughness height R in a mean length RSm of roughness profile elements in the range of 2,000 to 10,000 m according to JIS B 0601:2001 (ISO4287:1997) on a coating film formed by applying a ship bottom coating paint on a substrate and calculating a frictional resistance increase rate FIR (%) from a mirror surface by the following formula (1), wherein coefficient C is a constant depending on the kind of the roughness height R and a frictional resistance testing method, and is previously determined in such a manner that plural ship bottom coating films each having different roughness are subjected to a roughness measurement and a frictional resistance test in a definite evaluation length, and then the coefficient C is determined by the formula (1) using the roughness height R, the mean length RSm of roughness profile elements and the frictional resistance increase rate FIR (%), which have been measured.

An arrangement and a method for installing a propulsion unit to a hull of a ship. The propulsion unit comprises an upper part of the propulsion unit attachable to the hull of the ship and a lower part of the propulsion unit where to a propeller shaft is rotatably supported, and the upper part of the propulsion unit having flanges to attach the flanges tightly to the hull, and wherein there is an aperture in the bottom of the hull where to the propulsion unit is to be installed. The arrangement comprises a plurality of watertight covers covering openings in the bottom of the hull and a plurality of watertight covers covering openings in the top of the upper part of the propulsion unit, wherein the arrangement comprises a removable hull-side cover covering at least the opening under it, and at least one removable propulsion unit side cover covering the opening under it and facing the opening, and the removable covers are bolted from the hull-side.

An exemplary method is disclosed for estimating operational efficiency of a marine vessel with a propeller mounted to a rotatable shaft for converting rotative shaft power transferred from the shaft to the propeller into thrust to propel the marine vessel across water, the method including obtaining a respective time series of values for operating parameters of the marine vessel; constructing a multi-dimensional power matrix for a first time period based on operating parameter values within a respective sub-series thereof that represents a first time period; computing, for one or more propulsion parameters, fouling values based on information stored in the power matrix and information stored in a base matrix, of a reference fouling level; and creating indications concerning operating status of the marine vessel in dependence of the fouling values.

The present disclosure is directed toward a marine exhaust system in which the marine exhaust is directed into the water via an exhaust system integrated within a marine rudder. Exhaust travels from the engine to the rudder via a pipe or tube and is expelled through a cavity in the rudder outward into the water. A swivel is located in the system to allow the rudder to rotate in normal steering operations to allow at least a portion of the exhaust pipe or tube to remain static.

There is described a hinge for detachably connecting a door or window to a wall or a frame such as a windshield. The hinge comprising a shaft extending longitudinally, further comprising a blocker which is extendable about the shaft. A first socketed member is fixed to the shaft, and a second socketed member comprises a lumen for sliding the shaft therein. The lumen comprises a cavity larger than a remainder of the lumen and which defines an inward edge on which the blocker abuts, thereby retaining the shaft in the lumen. The shaft comprises an inner recess which can house the blocker therein if the inner recess is aligned with the blocker, thereby retracting the blocker from the cavity and releasing the shaft from the second socketed member and allowing the first socketed member and the second socketed member to be separated. This can be useful for detaching a door of a boat windshield, for example.

A submarine survey platform, including: a gasbag; a gas tube; a floater; an upper longitudinal plate; a lower longitudinal plate; diaphragm plates including upper openings, lower openings, and trapezoid openings disposed between the upper openings and the lower openings; and diagonal braces. The upper longitudinal plate includes a flat plate and a flanged plate. The lower longitudinal plate is a rectangular plate. The upper longitudinal plate pass through the upper openings, and the lower longitudinal plate pass through the lower openings. The diagonal braces and longitudinal stiffeners are disposed between every two adjacent diaphragm plates. Two diaphragm plates at two ends of the flat plate are provided with a lifting lug. The diagonal braces are symmetrically disposed and include outward braces and inward braces which are crossed with each other. Cross points of the upper/lower longitudinal plate with the diaphragm plates are support points of the upper/lower longitudinal plate.