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Maintenance of marine heat exchangers is important to ensure the small pathways in both types of coolers do not become fouled. Depending on the system different types fouling may occur. In oil based systems, an insufficient amount of cooling medium or inefficient flow of oil through the heater can cause the heater to become fouled.
Thermal treatment is a highly effective strategy for the control of zebra mussels (McMahon et al. 1995). Thermal treatment may include retrofitting a closed loop system to recirculate the heated water to the sea chest or the addition of a second sea chest system, allowing engine cooling water to be discharged through the idle sea chest.
The device is different from the Voith-Schneider marine propulsion system (also mechanically linked), which can also quickly change the direction of thrust, as the Z-drive uses a shrouded conventional screw that pivots or rotates the propeller, unlike the variable-geometry blades of the Voith-Schneider.
Add-on stability systems are designed to reduce the effects of waves and wind gusts. They do not increase a vessel's stability in calm seas. The International Maritime Organization International Convention on Load Lines does not cite active stability systems as a method of ensuring stability. The hull must be stable without active systems.
Copper sheathing is a method for protecting the hull of a wooden vessel from attack by shipworm, barnacles and other marine growth through the use of copper plates affixed to the surface of the hull, below the waterline. It was pioneered and developed by the Royal Navy during the 18th century. In antiquity, ancient Chinese used copper plates ...
Boats were admitted through double gates; the inside ones on the caisson "adjusted to fit close to those of the outer". [11] Congreve's patent then envisaged that having achieved "absolute equipoise" ( neutral buoyancy ) a rack-and-pinion , removable weights or a small winch could overcome inertia and move the caissons.
Other types feature a casing under the boat, which does not take up space but instead has the problem of increased drag. For this reason, it is not uncommon to find boats with a combination of shallow keel and centreboard (e.g. Randmeer). The keel provides the housing for the centreboard, moving it out of the hull, but adds only a small amount ...
Performance Handicap Racing Fleet (PHRF) is a handicapping system used for yacht racing in North America. It allows dissimilar classes of sailboats to be raced against each other. The aim is to cancel out the inherent advantages and disadvantages of each class of boats, so that results reflect crew skill rather than equipment superiority.