All About Marine Buoyancy Foam

Marine buoyancy foam is a closed-cell, lightweight material used in boats and other marine applications to provide flotation. Buoyancy, by definition, is the tendency of an object to float or to rise in a fluid when submerged. This fluid can be either a liquid or a gas.¹ In simpler terms, it's like a life jacket for your boat, helping it stay afloat in case of water ingress.

In the following article we investigate its purpose, regulations, and common types of marine buoyancy.

To comply with Australian Standards, most boats will at least have a neutral buoyancy. Neutral buoyancy, also known as level floatation2, occurs when the weight of the boat exactly equals the upward buoyant force meaning that the boat should neither sink nor rise when it is full of water and upside-down. Here are some benefits to using marine buoyancy.

• Keeps your Boat Afloat: The primary function is to provide buoyancy in case of leaks or capsizing. The foam fills compartments within the boat, displacing water and increasing overall buoyancy.

• Safety: By keeping the boat afloat, it enhances overall safety during emergencies.

• Leveling: Foam can be strategically placed to help maintain proper trim and balance of the boat.

Marine buoyancy foam needs to meet specific safety standards for both recreational and commercial vessels to ensure reliability and performance. These standards include AS1799 Small Craft Design Standard for powered craft up to 15 m in length used as recreational boats and the National Standard for Commercial Vessels (NSCV) for vessel design, construction and equipment for domestic commercials vessels. These Standards are enforced and maintained in conjunction with other international Standards by the Australian Maritime Safety Authority (AMSA) and typically address factors like flotation and stability.

Two main types of marine buoyancy foam are widely used. The ideal foam type depends on your specific needs. Here's a quick comparison to help decide:

· Pros: Long lifespan, 20 years+ (refer to test report), very low water absorption, fire retardant, superior chemical and UV resistance and durability, higher structural rigidity, easy to work with.
· Cons: High initial cost compared to EPE.

PJ Bowers recommends Neolon XPE for use in all commercial or survey required vessels.

• Pros: Lightweight, easy to work with, good water resistance and low cost.
• Cons: Short lifespan, 5 years (refer to test report), not fire retardant, no UV resistance, but fair chemical resistance.

Remember, it's always wise to consult with a boat builder or marine surveyor to determine the most suitable foam type for your specific application and ensure it meets the required standards.

If you are searching for great value marine buoyancy, check out AMSA recreational vessel approved EPE here and the superior AMSA commercial vessel approved Neolon XPE here. If you would like to learn more about marine buoyancy, check our articles here.

¹ Britannica Buoyancy Science

² AMSA Survey Newsletter