Why do we need to change over to the high suction sea chest during port stay?

The Low Sea Chest is generally used while the ship is in open sea and sailing with a moderate or deep draft. Using the High Sea Chest in open can cause the Main Sea Water pressure to drop as lesser water might enter the suction line of the pipe owing to rolling.

What is the use of high and low sea chest?

Vessels normally have a high sea chest, which is used in shallow waters to reduce intake of sediment, and a low sea chest, which could be used, among other things, when navigating in ice-covered water (to mitigate the intake of ice and slush) or when the vessel is rolling (to avoid losing suction).

How is sea chest fitted for shipping?

An enclosure, attached to the inside of the underwater shell and open to the sea, fitted with a portable strainer plate. A sea inlet valve and piping connected to the sea chest directs sea water into the ship for the cooling, fire or sanitary purposes.

What is the purpose of the sea chest?

A sea chest is a recess in a ship’s hull that houses pipes to take in seawater. Water is pumped in for cooling engines, washing decks and as ballast to stabilise the vessel. A sea chest has a grille to keep out large items, but this can also stop smaller organisms from being flushed out.

What is sea suction valves?

Introduction: Marine Suction sea valve is the inlet valve that installed at ship two sides, bilge or bottom. Approval Standard: 1. Chapter 2, Part 3 of China Classification Society Rules for Classification of Sea-going Steel Ships 2015 and Its Amendments.

What is Ship heat exchanger?

Heat exchangers are a kind of thermal machine widely employed on ships of every type, from cruise ships to large commercial ones, where they provide cooling of engines and hydraulic oil, in order to ensure the perfect lubrication and working conditions of each transmission and power system on board.

What is sea suction?

marine. The aperture through which sea water is drawn or the part of a pumping system which admits seawater into it.

What is a boat sea chest?

The sea chest provides an intake reservoir from which piping systems draw raw water. Most sea chests are protected by removable gratings, and contain baffle plates to dampen the effects of vessel speed or sea state. The intake size of sea chests varies from less than 10 cm² to several square metres.

What is a sea chest vent?

Having the vent allows air out at the high point but also allows water into the boat. The other end is inside the boat 12 to 18 inches above the water line.

Where are sea chest located?

Sea chests are mostly found in the engine room in the space between the side of the ship which is secured and protected by grids. These grids called ‘sea chest gratings’ prevent the passage of large objects such as trash, fish, nets, etc.

What is bilge and ballast system?

A bilge and ballast system is an interconnected network of valve manifold; pipelines, ballast tanks, dedicated valves with bilge and ballast pumps. The whole process consists of two key steps of ballasting and de-ballasting the ship; along with the added purpose to pump out bilges from cargo and machinery space.

What is sea water cooling system?

Seawater Air Conditioning (SWAC) is an alternate-energy system that uses the cold water from the deep ocean (and in some cases a deep lake) to cool buildings. In some areas it is possible to reduce dramatically the power consumed by air conditioning (AC) systems; SWAC can be a cost-effective and attractive investment.

What is the purpose of a high and low sea chest?

The reason for high and low sea chests is to avoid drawing mud and rubbish into your sea suctions when in port (high suction) and for getting the best seawater head and cleanest water when at sea (low suction). They also serve as a redundancy measure in the event that one or the other gets damaged or blocked. To change over is simple.

What happens to the sea chest when the ship is repaired?

The ship remains at sea, without having to go to dry dock. After the repair, the sea chest is unplugged and tested to verify that it operates properly and if necessary plugged again. The sea chests are in the space between the side of the ship and the sea suction valve.

How many sea chests are used in cleaning and painting?

(7) SEA CHESTS CLEANING AND PAINTING. All ships are fitted with at least 2-3 sea chests in the machinery space area. They are high sea suction , the low sea suction and the emergency fire pump sea suction. Their suction grids are to be dismantled and cleaned. The internal surface of the chests have to be scraped clean of all growth.

What maintenance is required for the sea chests and sea suction?

Zinc anodes in the sea chests are to be renewed. (8) SEA SUCTION AND DISCHARGE VALVES OVERHAUL AND SURVEY. All sea suction and discharge valves are to be overhauled at every dry docking. Every alternate dry docking they are surveyed. The air and/or steam connections to the suction boxes must be checked and any defects also attended.