Upgrading your watermaker's membrane
Upgrading your watermaker's membrane

Upgrade your watermaker's membrane to improve the quality and quantity of your fresh water supply while prolonging the life of your system - essential for any family embarking on a sailing adventure.

Upgrading Your Watermaker’s Membrane

As you embark on your sailing adventure with your family, one of the most important aspects of your journey is ensuring that you have a reliable and efficient water supply. A crucial component of this is your boat’s watermaker, which is responsible for converting seawater into fresh, potable water. In this article, we will discuss the importance of upgrading your watermaker’s membrane, the different types of membranes available, and the steps involved in the upgrade process.

Why Upgrade Your Watermaker’s Membrane?

The membrane is the heart of your watermaker system, responsible for filtering out the salt and other impurities from the seawater. Over time, the performance of the membrane can degrade, leading to a decrease in the quality and quantity of fresh water produced. Upgrading your watermaker’s membrane can provide several benefits, including:

  1. Improved water quality: A new, high-quality membrane can significantly improve the taste and purity of your drinking water, ensuring that your family stays healthy and hydrated throughout your journey.

  2. Increased water production: Upgrading to a more efficient membrane can increase the amount of fresh water your watermaker produces, reducing the time and energy required to meet your daily water needs.

  3. Extended system lifespan: Replacing a worn-out membrane can help prolong the life of your watermaker, preventing costly repairs or replacements down the line.

  4. Reduced maintenance: A new membrane may require less frequent cleaning and maintenance, allowing you to spend more time enjoying your sailing adventure and less time worrying about your water supply.

Types of Membranes

There are two main types of membranes used in watermakers: reverse osmosis (RO) membranes and ultrafiltration (UF) membranes. Each type has its own advantages and disadvantages, so it’s essential to understand the differences before deciding which one is best for your needs.

Reverse Osmosis (RO) Membranes

Reverse osmosis membranes are the most common type of membrane used in watermakers. They work by applying pressure to the seawater, forcing it through a semi-permeable membrane that filters out the salt and other impurities. RO membranes are highly effective at removing a wide range of contaminants, including bacteria, viruses, and heavy metals.


  • Excellent water quality: RO membranes can produce very pure water, with salt rejection rates typically above 99%.
  • Wide range of sizes and capacities: RO membranes are available in various sizes and capacities, making it easy to find one that suits your boat’s water production needs.


  • Higher energy consumption: RO systems require a significant amount of pressure to operate, which can result in higher energy consumption compared to UF systems.
  • More frequent maintenance: RO membranes can be more susceptible to fouling and scaling, requiring more frequent cleaning and maintenance.

Ultrafiltration (UF) Membranes

Ultrafiltration membranes are a newer technology that uses a slightly different filtration process. Instead of relying on pressure to force water through the membrane, UF systems use a vacuum to draw water through a porous membrane with much larger pores than RO membranes. This allows UF systems to filter out larger particles, such as bacteria and viruses, while allowing smaller molecules like salt to pass through.


  • Lower energy consumption: UF systems typically require less pressure to operate, resulting in lower energy consumption compared to RO systems.
  • Less frequent maintenance: UF membranes are less prone to fouling and scaling, which can reduce the frequency of cleaning and maintenance.


  • Lower water quality: UF membranes generally have lower salt rejection rates than RO membranes, which can result in slightly less pure water.
  • Limited size and capacity options: UF membranes are not as widely available as RO membranes, so there may be fewer options to choose from when upgrading your watermaker.

Choosing the Right Membrane for Your Watermaker

When selecting a new membrane for your watermaker, there are several factors to consider:

  1. Compatibility: Ensure that the membrane you choose is compatible with your watermaker’s make and model. Consult your watermaker’s manual or contact the manufacturer for guidance.

  2. Capacity: Choose a membrane with a capacity that meets your boat’s daily water needs. Keep in mind that higher-capacity membranes may require more energy to operate, so consider your boat’s power capabilities when making your decision.

  3. Salt rejection rate: Look for a membrane with a high salt rejection rate, as this will result in better water quality. RO membranes typically have salt rejection rates above 99%, while UF membranes may have slightly lower rates.

  4. Ease of maintenance: Consider how easy the membrane will be to clean and maintain. UF membranes generally require less frequent maintenance than RO membranes, but this may vary depending on the specific product.

  5. Price: Finally, consider the cost of the membrane and weigh it against the benefits it will provide. While a more expensive membrane may offer better performance and longer lifespan, it’s essential to find a balance that fits your budget and needs.

Upgrading Your Watermaker’s Membrane: Step-by-Step Guide

Once you’ve chosen the right membrane for your watermaker, it’s time to perform the upgrade. While the exact process may vary depending on your watermaker’s make and model, the following steps provide a general overview of the procedure:

  1. Turn off the watermaker: Before starting any work on your watermaker, ensure that it is turned off and disconnected from any power sources.

  2. Remove the old membrane: Carefully remove the old membrane from the watermaker’s pressure vessel, following the manufacturer’s instructions. Be sure to wear gloves and eye protection, as the membrane may be contaminated with salt and other impurities.

  3. Clean the pressure vessel: Thoroughly clean the inside of the pressure vessel, removing any debris or buildup that may have accumulated over time. This will help ensure that your new membrane operates at peak efficiency.

  4. Install the new membrane: Carefully insert the new membrane into the pressure vessel, making sure it is properly seated and aligned. Follow the manufacturer’s instructions for any specific installation requirements.

  5. Reassemble the watermaker: Once the new membrane is in place, reassemble the watermaker according to the manufacturer’s instructions.

  6. Flush the system: Before using your upgraded watermaker, it’s essential to flush the system to remove any air bubbles or contaminants that may have been introduced during the installation process. Follow the manufacturer’s instructions for flushing and priming the system.

  7. Test the watermaker: Finally, test your watermaker to ensure that it is producing fresh, clean water at the desired capacity. If you encounter any issues, consult the manufacturer for troubleshooting assistance.


Upgrading your watermaker’s membrane is a crucial step in maintaining the efficiency and reliability of your boat’s water supply. By understanding the different types of membranes available and following the proper installation procedures, you can ensure that your family stays healthy and hydrated throughout your sailing adventure.