Closed cell polyethylene foams and engineered foams from Polyformes are ideal for marine buoyancy, structural support, boat stiffening and flotation applications. Whether you're building a hull, outfitting a life vest or manufacturing fenders, our foam conversion solutions combine durability, lightness and long-term performance at sea.
At Polyformes, we manufacture and supply high performance marine and flotation foam for durability, safety and buoyancy in harsh marine environments. Our closed cell foams, including Plastazote®, Evazote® and Ethafoam®, are trusted in marine, sailing, boat building, offshore and rescue industries for their outstanding waterproof, UV-resistant and impact-absorbing properties.
Closed cell polyethylene foams from Polyformes are superb for marine buoyancy applications. With Plastazote LD15 foam being the lightest foam available at 15kg/m3, it is particularly suitable for use as formers in hull stiffening ribs and stringers of large fibre reinforced plastic (FRP) boats. EF220 Ethafoam (35kg/m3) will often be used in these applications too as it is a large board size in its virgin form. This makes it easy to cut into longer sections for stringers or positive buoyancy blocks.
Man Overboard stretchers and cradles can utilise the expanded polyethylene foam. Many lives have been saved by these SOLAS approved items. The buoyancy of the foam ensures complete flotation support.
Horseshoe lifebuoys and foam vests can be made without additional coverings keeping costs down and buoyancy high. The Evazote and Plastazote foams used for these purposes are highly water and uv resistant thus lasting for many years under standard usage. EF220 Ethafoam is often used in fabric covered life-vests as a low cost, easily shaped option.
Professional buoyancy aids manufactured using foam achieve the 50-100 Newtons of buoyancy required to conform to the International CE standard EN393. Some premium jackets offer fixed foam buoyancy of 100N and are officially classed as lifejackets as they turn you into the upright position once in the water.
Foam buoyancy aids have great advantages over inflatables as they will not puncture, and unlike polystyrene, will not break or come apart. When participating in active water-sports such as water-skiing or jet-skiing, the foam retains its shape, cushioning and buoyancy properties whatever impact there might be.
Many RIBS (rigid inflatable boats) are replacing the pneumatic tube systems, which are susceptible to puncturing and deflation, with foam fenders and sections. Being closed cell, flexible and resilient, they cannot puncture, the maintenance is minimal, no air checks are required and they are very cost effective.
Buoys—cylindrical, anchor pendant, navigation and marker—will usually have a closed cell foam flotation core rather than a urethane foam core as this ensures the buoy will not absorb water even if the outer skin is punctured. The pe foam make the buoys self-fendering with a high impact absorption capacity. It is usual for the buoys and fenders to have a closed cell polyethylene foam core and an outer skin of reinforced polyurethane elastomer. This proves very economical as even after many years in service, the foam core can be re-skinned. Flat fenders in semi-rigid pe foam are ideal as dual-use fenders and cushions. As these can be made in any size or shape, they will fit any vessel area.
Tubular hose floats for dredging, oil terminals and environmental areas can be made in standard or bespoke sizes, as can safety booms and bridge protectors. Curtain booms, for both short and long term deployment in harbours, rivers, ponds, dams, oil terminals, utilise the pe foam. Many foam filled standard or curtain booms are made in section lengths that can be joined to suit the specific requirement at the time.
The diving industry and scuba fraternity are big users of our waterproof Explorer Cases for carrying and using all forms of equipment including oxygen cylinders, full dive outfits, nautical and navigational instrumentation as well as medical equipment. You can protect your diving gear and essentials not just during transit but also in situ. These watertight and submergible cases will ensure your kit remains dry and safe whether in the water, on a boat or on the road.
Closed-cell foams will not take on water, even under prolonged submersion, making them superior to materials like polystyrene in demanding marine environments.
Our foam grades such as Plastazote®, Evazote® and Ethafoam® resist UV degradation, oils, salts, and sea environment chemicals.
Lightweight foams like Plastazote LD15 add strength without weight, suitable for hull ribs, stiffeners, and buoyancy inserts.
Foam blocks designed to meet SOLAS / EN buoyancy standards (e.g., 50–100 Newtons) help ensure flotation even under load.
Foam will maintain shape, cushioning and buoyancy even during rough handling, jet-skiing or sport use.
| Application | Foam Type | Benefit |
|---|---|---|
| Hull stiffeners & ribs | Plastazote® LD15 | Lightweight, easy to shape |
| Positive buoyancy blocks | Ethafoam® EF220 | Strong, cost-effective |
| Lifejackets & vests | Evazote® | UV-resistant, flexible |
| Fenders & buoys | PE Foam | Impact-absorbing, re-skinnable |
| Hose floats & booms | Closed-cell PE | Waterproof, adaptable design |
Use Plastazote LD15 (approx. 15 kg/m³) for rib or stringer formers in fibre-reinforced plastic hulls. Ethafoam EF220 (approx. 35 kg/m³) is effective for longer floats or structural sections that demand more rigidity.
Foam cores in safety products like vests and cradles support flotation, often achieving 50–100 N buoyancy per EN/CE standards. Non-inflatable foam solutions are often preferred for durability and resistance to puncture compared to inflatables.
Foam fenders for boats, buoys, and booms use closed-cell cores covered by reinforced skins (e.g., polyurethane elastomer) to resist puncture and maintain shape. Tubular float sections and curtain booms for containment or marine infrastructure use foam cores custom-sized for load and buoyancy needs.
Waterproof cases for dive gear and instrumentation benefit from foam interiors that protect, float, and cushion against impact.
At Polyformes, we supply bespoke marine flotation foam blocks, custom buoyancy solutions, and marine-grade foam inserts trusted by engineers and manufacturers worldwide. Get in touch to discuss your project, or explore our related pages:
Foam used in marine flotation often needs to comply with regulations or standards such as EN 393 / CE buoyancy, SOLAS (Safety of Life at Sea) regulations, and guidance from the UK Maritime & Coastguard Agency (MCA). Some foam systems (e.g. polyurethane flotation foams) also utilise lower formulations to comply with environmental regulations.
Some foam systems, including closed-cell polyethylene and polyurethane foams, are formulated to comply with UK environmental regulations, reducing chemical leaching and ensuring eco-friendly use in harbours, rivers and coastal waters.
When designing flotation solutions, it's crucial to validate buoyancy, compressive strength, and long-term durability under cyclic immersion, saltwater exposure and varying load. This ensures consistent performance for life-saving and marine safety applications.
Closed-cell polyethylene foams like Plastazote® or Ethafoam® are best as they don't absorb water and maintain buoyancy for years.
Marine grade foams are used in buoyancy aids, boat hulls, fenders, floats, booms and diving equipment cases, wherever lightweight waterproofing and flotation are needed.
No – closed-cell marine foams are waterproof and non-absorbent, unlike open-cell foams or polystyrene.
Yes, at Polyformes we can CNC machine or waterjet cut marine foam to precise tolerances for custom projects.
Most buoyancy aids made with closed-cell foam achieve 50–100 Newtons of buoyancy to meet EN393 / CE certification standards.
It depends on density. For example, low-density foam like LD15 yields higher buoyancy per cubic metre than a denser foam used for structural strength.
Yes. High-quality marine flotation systems use pour-cell polyurethane foams with closed-cell structure to fill voids, creating rigid buoyancy blocks for OEM marine foams.
High-grade closed-cell foams resist water absorption and UV for many years. However, extreme environments and abrasive wear may require periodic inspection or replacement.
