Reinforcing a Bulkhead Properly: Beam Theory, Uni-Directional Fibre & Multihull Structure Explained

Sun, 04 Jan 2026 16:00:37 +0000

Bulkhead reinforcement isn’t about adding more fibreglass—it’s about understanding how loads actually move through a boat.

In this video, we reinforce a small but critical section of bulkhead on Paikea, our Lock Crowther Catana 42s, and use it to explain:
Why bulkheads act as structural beams
How span, depth, and stiffness dictate laminate design
When uni-directional fibre is required (and when it isn’t)
The difference between edge capping and true structural reinforcement
Why we chose polyester and E-glass instead of carbon and epoxy
Real-world trade-offs between performance, cost, and practicality.

This is not a cosmetic refit. It’s structural work driven by basic beam theory and offshore reality. If you’re refitting a multihull—or assessing one—this is the kind of detail that matters.

CHAPTERS
00:00 Why this bulkhead matters
02:10 Are we creating an I-beam?
05:40 Span vs depth explained
09:30 Uni-directional fibre vs edge capping
14:10 Deflection vs strength
18:45 Material choices: polyester vs epoxy
23:10 Doors, openings, and structure
26:40 Final laminate and edge capping

USEFUL LINKS
➜ Supporting blog post https://youngbarnacles.com/
➜ Want to go deeper? Access our detailed composites videos, project files, and community on the Youngbarnacles Members Hub: https://youngbarnacles.com/plans/all-access-memberships/
➜ Need world-class engineering for your project? Learn more about our professional design and consultancy services at SYAS Performance: https://syasperformance.weebly.com/
➜ Free Sailing Library: Check out our free guides on composites, systems, and seamanship: https://www.youngbarnacles.com/resources

MUSIC
YouTube Audio Library ➜ https://www.youtube.com/

SAFETY DISCLAIMER: PROFESSIONAL WORK
This video documents professional marine work with significant risk of injury or vessel damage. This is NOT DIY instruction. You are solely responsible for your own safety and actions. We are not liable for any application of this information.
Full Disclaimer: https://youngbarnacles.com/website-disclaimer/