Foam Series: Selecting the Right Marine Exterior Foam

For marine exterior projects where water resistance is a top concern there are two types of foam that we recommend: closed cell foam and polyurethane antimicrobial foam. We have different recommendations for foam based on what type of boat seating you’re making cushions for. Is your project cockpit cushions for a sailboat or upholstered seating on a powerboat or pontoon? Let’s take a closer look at your project needs and which type of foam is best for your specific application.

Powerboat or Pontoon Seats

If you’re upholstering seats on a powerboat or pontoon, we recommend using either a medium density or high density polyurethane foam with antimicrobial properties. Polyurethane foam soaks up water, so we don’t recommend using it for cushions that will be covered in a woven fabric; however, since powerboat seats are typically upholstered in vinyl, this is a comfortable and affordable option. The vinyl fabric is waterproof and will keep your foam nice and dry underneath.

Medium density polyurethane is the standard foam used by OEM boat builders, while high density will last longer. It should also be noted that medium density is approximately 35% to 40% less expensive than high density and, therefore, might be a better option for weekend boaters who don't need the longevity and durability of high density foam.

Sailrite's medium density foam offering is CushionRite® Standard Antimicrobial Foam. Choose from three firmness levels (soft, medium and firm) and a wide variety of sheet thicknesses and sizes. CushionRite® Premium (Firm) is our antimicrobial high density foam. With a density of 2.8 pounds per cubic foot, it will last up to 12 years.

Sailboat Cockpit Cushions

For cockpit cushions in a sailboat, we recommend using CushionRite® Flotation Antimicrobial Foam. We lean toward this type of foam because cockpit cushions often end up in the water and we want to prepare for that possibility. It is a great choice for liveaboards and other frequent cruisers because it is a high density (3-4.5 pounds per cubic foot) foam and will hold up to daily use for years and years. It is also firm, so it’s great for boats where the cushions are frequently stepped on.

A great plus of closed cell foam is also that it floats, so cushions made from it can double as flotation devices. It's also a popular foam choice for bosun's chairs. Cover CushionRite Flotation Foam in any type of marine fabric you choose since it’s water-repellent and won’t be hurt by moisture.

Ultimately the choice is yours in regard to which foam you think will best suit your needs. To learn more details about each type of foam mentioned here (and more!) check out our “Comparing Types of Cushion Foam” post (#300053XHT). You can also read more about important terms to know when researching foam in our “5 Important Foam Terms to Know” post (#300052XHT).