A comparison: Plastic versus steel buoys

21st Jun 2020
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A Comparison Between Two Major Technologies: Plastic and Steel Buoys

Being in the market since 1860, GISMAN benefits from extensive experience in the design and supply of floating Aids to Navigation (AtoN) solutions for the marine and river industry. In the early 1990s, GISMAN was acknowledged as the pioneering designer and manufacturer of modular plastic navigational buoys with rotational molding polyethylene (PE) float. However, GISMAN also won many major contracts for buoys 100% made of steel, allowing us to give an objective comparison between the two major technologies: plastic and steel buoys for (semi-)exposed, open sea and offshore environments.

As a side note, a plastic buoy is defined as a floating aid with at least the hull being constructed of a plastic material, as per IALA guideline no. 1006 dated December 2008 on Plastic Buoys.

A comparison:

Plastic Steel
Location ⇒High exposure to UV rays will speed up the ageing process of plastic parts. Color fastness within IALA chromaticity standards can be guaranteed for years, if virgin material & high-quality PE pigments are used in the manufacturing process.
⇒PE can expand and contract with temperature variations, however, this should be taken into consideration during the design phase.
⇒High exposure to UV rays will speed up the ageing process of painted parts. Blasting & painting operations onshore will need to be scheduled more often.
⇒An increase of temperature by 10 degrees Celsius can speed up twice the oxidation on steel material. Important to keep in mind for regions such as the Middle East.
Installation Reduced lifting capacity.
Less servicing vessels for deployment.
No coating equipment.
Heavy lifting facilities.
More servicing vessels.
Coating equipment.
Maintenance ⇒Corrosion inspection on steel central structure, only in case of hybrid buoy.
⇒Small maintenance operations on deck of service vessel.
⇒Corrosion inspection key, as buoys are made of 100% steel.
⇒Onshore maintenance, grit blasting & painting operations.
Collisions & Damages Hull impact resistance provided by thickness of float. Float filling with expanded polystyrene or polyurethane foam ensures buoy keeps its buoyancy, even when damaged. Modularity of polyethylene float, made of 2 or 4 quadrants, provides an additional advantage & is easily interchangeable. Steel float provides a good impact resistance. Watertight segmentation of the buoy body is costly and makes the buoy heavier. When steel float is ripped, the entire buoy may sink & be replaced.
Storage Reduced surface storage area, as large plastic floats are from modular design. Significantly more surface storage area.
Environmental Impact ⇒Less maintenance, less control visits.
⇒Modular design & reduced weight of PE buoys imply less servicing vessels & fuel consumption.
⇒Low & high density PE is 100% recyclable, provided that any metallic components (in case of hybrid buoy) and impurities like marine growth are removed beforehand.
⇒More intensive maintenance, more visits.
⇒Heavier weight & more servicing vessels imply more fuel consumption.
⇒Coating equipment necessary.
⇒Steel recycling process is well established.

 

Some of the latest discussions on LinkedIn with regards to this topic unfortunately do not take into account there are now new models of marine buoys in the market, such as modular buoys consisting of 2 to 4 sections that are interchangeable and can easily be removed & replaced, and hybrid buoys with steel central structure and PE float, each offering numerous advantages. The type of foam used is another key differentiating element (EPS versus PU), making a difference in durability, water tightness, buoyancy, environmental impact, just to name a few.

A more in-depth document with the comparison between both plastic (PE) and steel buoys is available. If PE over Steel is out of your comfort zone, Ecocoast can offer training support, as well as guidance with specifications. Contact our expert sales team today at [email protected] or call +971.4.885 3944.  

In case you missed some of our previous Aids to Navigation blog posts, check these out:

Goodbye faded buoys, hello GISMAN, master in rotomolding

Moorforce, our advanced mooring calculator, has been launched

Hyperion marine lanterns, an introduction (in Arabic)