What is a seachest ?
In ships, sea chests are nothing but a suction point/port. This is the first point of entry onboard from where all systems that require seawater (e.g cooling) take from. Think of it as a vast reservoir, one side open to the sea, and on the other side, a pipeline opens to the ship.
Sea water uses ?
Onboard a a lot of plate heat exchangers are cooled via seawater. These systems can total to a huge amount of water needed, good thing we are in the sea hey ?
High seachest or low seachest ?
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. The Low Sea chest is not used for shallow or confined waters to prevent the sucking up of mud/plastic etc.
Fouling of a seachest
The seachest either high or low seachest have grills on them to stop the intake of large objects. Many seafarers will be able to tell you how far from China they are by the amount of plastic and rubbish in the waters.
The seachest contains a strainer which sits as a filter to stop fish, plastic or seaweeds being sucked into the seawater systems. Below the pictures will show how blocked the strainer can get blocked up.
