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Sea Water Systems

Sea Water Systems

We, Sal Marine, are the premier distributors of sea water systems, seawater filters and waterlock mufflers specially designed to keep your boat's engines cool, clean and long-lasting for both boat owners and boat-providing companies.

We offer everything required for your best sea experience, from inflatable boats to their engines, from seawater filters to small parts of the boats and cleaning agents for their maintenance & upkeep.

What are Sea Water Systems?

Sea water systems are water-purifying systems installed in a boat/ship/yacht/cruise that uses the deep cold seawater as the chilling agent to cool down the engine. Likewise, it is also used as a fire extinguisher to chill the onboard air conditioning system to keep the air cool. Hence, it is also known as Sea Water Air Conditioning (SWAC), Sea Water Cooling System and Ocean Water Cooling System.

However, we can not use seawater directly in the engineering system, as any unwanted material and pollutants in seawater may damage the piping network of the boat, ship, yacht or cruise. Some unwanted seawater materials are sea animals, human wastes, plastics, plants, sea animals, shells and wood. And to clean these pollutants, we use seawater filters and strainers to store the fresh seawater to cool down the boat engine.

How Does the Sea Water System Works?

This is the question most frequently asked by customers: How does a Sea Water System work?

This guide is perfect for you, as you will understand what happens in every step of the filtration process. Moreover, this guide will also help you understand the necessary steps to take during a breakdown or maintenance issue.

Therefore, keeping that in mind, let's learn how a seawater system works:

The process starts with seawater getting pumped into the sea cock through an inlet and stored on the lower side of the sea cock with the help of a water pump. Then the water is pushed through the seawater filters & strainers to capture pollutants and other particles from the seawater.

Filtered seawater is stored on top of the filter and then pushed through the outlet straight to the engine and out to the exhaust to keep the engine cool. In this process, the filtered chilled water of the sea absorbs the heat from the engine to keep it cool. Typically, seawater flows from the inside to the outside of the filter elements to ensure maximum capturing of unwanted particles.

Traditionally, the procedure goes on until the filter elements get clogged. Clogging of the filters results in increased differential pressure of the seawater. Because of this, the passage of the seawater and the filtration process will be halted until and unless you clean the filter elements.

However, in modern seawater filters, you don't have to clean the filter & strainer elements anymore. Modern seawater filters contain a clogging indicator that will start to flash when the level of the clogging is reached or about to reach. After that, the inlet and outlet valve will automatically close down while the drainage and backwash valve will open up to remove the pollutants from the filter.

In order to clean the filters, water pumps from the source will pump the under-pressure water into the backwash valve. Then the drainage valve will discharge the pollutants and water out of the seawater filter. In some seawater filters, two filter elements are present to guarantee the filter's continuous operation. As a result, while one filter element is being unclogged, the other continues to function at its best.

Moreover, to keep the water clean, there are many parts in a seawater system that helps to keep the water clean for proper cooling and piping network.

Parts Used in a Seawater System are:

Vetus Waterlock: 

Vetus waterlock is an outside water-storing part of the seawater system. The water is pushed into the exhaust system to cool the engine & the exhaust gases. Then the water containing engine heat and exhaust gases is released outside via the water lock exhaust outlet. A Vetus Waterlock in such a system ensures that the outside water in the exhaust cannot flow back to the engine.

Waterlock Muffler

A waterlock muffler is horizontal stainless steel with neoprene bellows water-cooling exhaust muffler with a 57mm water lock system. It is an effective silencer keeping the engine exhaust noise silent with a minimum back pressure. As the name suggests, it also functions as an effective water lock, keeping the backflow of water from entering the engine again and protecting the pistons and cylinder from harm.

Seawater Filter

Seawater filters are a strainer to clean water impurities to protect downstream equipment like bilge pumps and engines from heating and piping blockage. The availability of desalinated water on demand allows you to travel further and for longer periods of time without adding weight to your vessel.

Airvent Anti Syphon

When the engine is stopped, there is a potential that cooling water will syphon into the exhaust system and ultimately into the engine itself if the cooling water injection point in a boat's exhaust is less than 15 cm (6") above the waterline. Therefore, the Airvent Anti Syphon is a device that helps to prevent colling water from siphoning back into the exhaust system and subsequently into the engine itself.

Anti-syphon devices are reliable pressure valves and are Self-contained.


The seawater system is simple. However, some processes and terms are confusing, but with time you will understand them easily.

All you need is a good quality seawater filter for your seawater system that can purify that polluted seawater to the desired level you want.

Therefore, contact Sal Marine today for the best quality seawater system products for your boats, and you will never regret purchasing from us.

Explore Our Categories For More Boat Parts

Boat Parts - Anodes | Bilge Pumps | Control Cables | NMEA 2000 | Kill Cords | Engine Controls | Fuel Systems & Filters | Stern Tube Glands & Seals