Marine Buoyancy Foam

Marine Buoyancy Foam: Keeping Things Afloat

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.

Why is marine buoyancy used?

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.

What are the marine Buoyancy standards?

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.

Common buoyancy material types and their comparisons

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:

Cross-Linked Polyethylene (XPE) Foam

· 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.

Expanded Polyethylene (EPE) Foam

• 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.

EPE & Neolon XPE Comparison

Neolon XPE Sheet Foam Product image thumbnail

Neolon XPE Closed Cell Foam

One of our speciality recycled foams, for many applications:
marine, packaging and construction.
With many properties such as flame retardant, fuel and UV resistant.

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EPE Closed Cell Foam

A budget-friendly packaging and marine floatation foam.
All our closed cell foams are waterproof.
EPE can be machined and cut as any other closed cell foam.

Visit Product Page

Feature

Neolon XPE Closed Cell Foam

EPE Closed Cell Foam

Standards & Certifications

Fire Retardancy:
ASTM 1530.3, BS EN ISO 4589 3:2017
Construction Certification:
MRTS77, RTA 3204
Marine Certification:
NATA 14722
CE Certification
Meets UL94 Standards

Marine Certification: NATA 14722

Neolon XPE is manufactured by a more involved process that expands the foam with a cross-linked structure. Giving the foam greater strength in all areas.

EPE foam is not crosslinked, a more affordable manufacturing process that reduces the resilience and longevity of the foam.

Water Resistance

Neolon XPE is of course, a closed-cell foam meaning water or air cannot pass through the foam. When tested and submerged in water for long periods of time the foam only holds 0.09 grams of water per cm².

EPE foam is not crosslinked, a more affordable manufacturing process that reduces the resilience and longevity of the foam.

Chemical Stability

Neolon XPE has been tested by submerging the foam into chemicals such as high octane petrol, diesel oils and even bilge cleaner for weeks. There was no effect or damage to the foam, therefore the buoyancy of the foam remained unchanged.

EPE has good chemical resistance, but over time repetitive cycles of any stress (heat or mechanical) can cause EPE breakdown.

Strength, Durability and Longevity

Neolon XPE can recover quickly from heavy impacts or compressions, it's longevity is tested to be greater than 20 years with exposure to UV and heat cycles and is commonly used as expansion joint material in heavy-duty applications such as roads & bridges.

EPE is prone to breakdown when exposed to UV or heat cycles. It can become brittle and soft on the outsides before breaking down further over time. EPE can squash and not recover if it experiences a strong enough impact.

Thermal Insulation

Neolon XPE has great insulation qualities, that is why we apply our foil face to Neolon XPE and manufacture our insulation tubes from Neolon XPE.

EPE will breakdown if exposed to heat cycles, which is very likely in insulation applications. Can work well for limited use packaging applications.

Fire Retardant

Neolon XPE is a certified flame and ignition retardant material. This is absolutely necessary for marine and construction applications.

EPE has no fire or ignition resistant properties.

Total Score
(Our recommendation for quality, long-lasting LDPE when used in marine buoyancy applications.

32/35

14/35

In Short

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 https://www.britannica.com/science/buoyancy

² https://www.amsa.gov.au/news-community/newsletters/survey-matters-february-2020

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