Abstract: A valve (1,1?) for a marine propulsion unit comprises a body (2) having an internal passage (3) through the valve body (2). An aperture (5) in the valve body communicates with the internal passage (3). A piston (4,4?) is moveably mounted within the internal passage. The valve is configured such that, upon immersion or expected immersion of part (such as an air intake) of an associated propulsion unit in water or tilting of the associated propulsion unit beyond a predefined angle, the piston moves to a first position within the internal passage in which it seals the aperture. If for example the air intake of a marine propulsion unit of a vessel is connected to the aperture (3), the effect of the piston sealing the aperture (5) is to isolate the air intake from the atmosphere. Thus if the vessel sinks or capsizes, the valve closes the air intake of the propulsion unit and so prevents entry of water into the propulsion unit.

Abstract: An ultra-lean dilution apparatus is provided for proportioning minute quantities of a first fluid, such as a concentrated cleaning solution, for mixing into a second fluid, such as tap water, which provides improved performance and which can be manufactured by assembling several molded components with little or no machining. The dilution apparatus (20) provides a selective pressure drop in a conduit (22) by including a plurality of dilution disks (50a-50f), each dilution disk (50a-50f) having a tortuous path (52a-52f) of sufficient cross-sectional area to be resistant to clogging and having a sufficient number of sharp turns to create a desired pressure drop. While each disk (50a-50f) produces a predetermined drop, the serial configuration of the tortuous paths of the plurality of dilution disks is additive to produce a range of dilution suitable for the chemicals used.

Abstract: The scour jet array system includes a pump, both fresh water and surface er intakes, an automatic water mixing valve, a chemical buffer injector, a water heater, a series of scour jets with control valves, and a central control system.The control system senses the beginning of ebb tide for starting an initial scour jet, and as each jet scours the freshly deposited mud from the area, temperature, salinity and pH of the surface suction intake water are measured to determine the amount of fresh water injection, chemical buffer injection, water heating and duty cycle time in order to minimize the energy required to scour the sediments from the area.