Building Carbon Fibre Chainplates: Part Three — The Starboard Side

Building Carbon Fibre Chainplates: Part Three — The Starboard Side

The rudder project running through this same stretch of time wasn’t happening in isolation — there was a lot going on aboard Paikea at once, and this starboard chainplate rebuild was one of several things competing for attention in the same tight window. It’s worth setting the scene: this all happened in Martinique, in the Caribbean, with six days on the clock to finish every open project and get Paikea ready for an Atlantic crossing back to Europe, driven by a job offer that had come up for Shayne in Spain. Not exactly ideal conditions for a second full chainplate rebuild — but the starboard chainplate was pulling out of the deck, same as the port side had, and with the whole return crossing set to be sailed on starboard tack, there wasn’t room to leave it as-is.

The good news, and it genuinely was good news, was that this side didn’t require solving the problem from scratch. The template used for the port side chainplate had been cut from foam with the working assumption that both sides of the boat were symmetric — both pieces cut out at the same time, on the theory that fore-and-aft structure this far forward would mirror itself port to starboard. That’s not always a safe assumption on a boat; symmetry that looks obvious from the outside often isn’t remotely close once you actually measure. In this case, though, it held up — Paikea turned out to be genuinely symmetric at this bulkhead, which meant the port side template could be reused directly rather than re-templating the whole job from zero.

The underlying cause was identical to the port side too: the plywood core inside the bulkhead had rotted, the same slow deterioration accelerated by humidity, and the chainplate itself was visibly moving — bolts pulling through in a way that made continued sailing on that side a real risk, not a theoretical one.

Pulling the old hardware and structure apart followed the same process as before: removing the stainless steel side stay, taking the halyards onto the rig temporarily to keep tension managed while the chainplate came out, then working bolt by bolt to free the old strap chainplate from the deck and bulkhead. One extra step this time was removing a stainless steel alignment tube that had been built into the original carbon chainplate lamination — a sleeve specifically included to keep the pin alignment correct through the strapping, now needing to come back out cleanly as part of the disassembly, with a quick check that it had stayed straight after being bonded in.

Once the old structure was fully out, the thickness of the new carbon chainplate became genuinely visible for the first time — measuring out at around 10mm through the strap itself. That thickness isn’t arbitrary; it’s the direct result of the layer count built into the layup, engineered to the same safety margin used on the port side.

One detail worth calling out on its own: the edge capping applied around the new bulkhead once the chainplate was bonded in. It’s tempting to think of edge capping as a cosmetic finishing touch, but its real job is structural — tying the two fibreglass skins together across the edge of the bulkhead, creating genuine continuity from one side to the other. Without that, a big wave load pushing against the panel can cause the skins to want to bend, buckle, and separate from the core underneath. Done properly, edge capping stops that from happening. The original edge capping on this boat, inspected during the teardown, turned out not to be doing this job at all — some chop strand mat had been wrapped around the edge, which covers the foam and looks finished, but chop strand mat is discontinuous fibre. It has no meaningful capacity to structurally tie one skin to the other; it’s essentially a cosmetic edge dressing that happened to also be there. The new edge capping, laminated properly in double bias fibreglass, does the actual structural job the original one only appeared to do.

The Kevlar question came up during this build too, and it’s a fair one — Kevlar has genuinely excellent properties, particularly in shear tear resistance, and it’s a material people reasonably ask about for chainplate applications. The honest answer is that it’s technically possible, but a genuinely difficult material to work with well. Getting proper fibre impregnation with Kevlar is hard even under vacuum infusion, and it’s close to impossible to achieve reliably by hand lamination — full bundle impregnation just doesn’t happen easily, no matter how careful the technique. Even cutting Kevlar cleanly is its own particular pain. E-glass would have worked perfectly well structurally for this application too, with carbon chosen mainly for the weight advantage it offers over glass — a real but relatively modest gain, not the dominant factor in the decision.

With the starboard side finished, both chainplates were now rebuilt to the same carbon fibre system, on the same tight structural logic: load distributed through bonded surface area rather than concentrated at bolted hard points, proper edge capping tying the bulkhead skins together, and a full understanding of exactly how much margin was built into each one. Six days, two rebuilt chainplates, and an Atlantic crossing back to Europe still to come.

In This Series

This post is part of our chainplates deep dive. Read the full story here: Paikea’s Chainplates – The Full Story

Or explore the rest of the series:

In the Members Library

We’ve put together the complete photo build log for this one — from the first bolt that told us something was wrong through to the finished, painted chainplate. See the full build on the members page.