Sailing Umavideo
We Ran an Experiment: Is Foam Really Better Than Plywood ? | Step 441
May 23, 2025 · 28 min · 124K views
What this video covers
A comparative structural test of marine plywood versus foam-core composite panels reveals that 20mm marine plywood offers higher load-bearing strength than equivalent foam-core laminates at a significantly lower cost. Using a custom-built test rig and a digital crane scale, the crew of the 9,000-kilogram vessel Uma measured the force required to deflect and break various samples, including 12mm and 20mm marine plywood, and foam panels laminated with varying weights of glass fiber and resin. Results showed that 20mm marine plywood failed at 66.8 kilograms of force, while foam-core samples with 1,200 grams of glass per side failed at lower thresholds. The testing also indicated that vinyl ester resin produced stiffer, lighter, and stronger laminates than West System epoxy in these specific configurations. Financial analysis determined that building the boat’s bulkheads from foam and vinyl ester would cost over three times more than plywood, while epoxy construction would cost nearly eight times more, with minimal weight savings relative to the total displacement of the boat.
More from Sailing Uma
From Sailing Uma — see the channel’s boat, crew, and every analyzed video.
The Sailing Directory Newsletter
One email with the fleet's best finds — the moments, boats, and stories worth your watch time. Enter your own address to get your own copy.