Photograph

Why HDPE

A welded HDPE hull compared with aluminium and fibreglass

Every boat LarsenB offers today has a welded HDPE hull. HDPE is high-density polyethylene. It comes as thick plate and is welded much like metal, so the hull is built up from plate instead of being moulded. Here is how it compares with the two materials most workboats are made from.

Side by side

	HDPE	Aluminium	Fibreglass (GRP)
Impact	Flexes and returns to shape	Dents, and holds	Can crack or delaminate
Corrosion	Does not corrode	Needs anodes and care with mixed metals	Does not corrode, can blister
Upkeep	No painting. No antifouling in fresh water	Anodes and coatings	Gelcoat and antifouling
Noise on board	Dampens vibration and water noise	Resonates more	In between
Plate	About three times thicker than aluminium at the same hull weight	Thinner plate	Set by the laminate
Repair	Can be welded on site	Weldable, harder in the field	Usually a specialist workshop
Sunlight	Stable	Not affected	Relies on its gelcoat
End of life	Fully recyclable	Recyclable	Hard to recycle

Against aluminium

Aluminium is a proven material for professional boats, and many public tenders still name it. HDPE's case starts with the plate: at the same hull weight it can be about three times thicker, so a knock that would dent metal is taken up by the material. There are no anodes to replace and no galvanic corrosion to manage, and less engine noise reaches the crew. If your tender leaves the material open, an HDPE hull is worth putting beside the aluminium ones.

Against fibreglass

Fibreglass suits leisure boats well. Working boats are harder on it. A rock, a quay or a floating log can crack the laminate, water then gets into the structure, and the repair usually needs a dry workshop. HDPE does not absorb water or blister. Its colour runs through the material, so there is no gelcoat to keep up.