Why Weight Is Critical on Your Multihull
Every self-tapping screw on this boat has been weighed. Not because it matters individually — because the sum of a hundred small things nobody thinks to weigh always adds up to more than expected.
Before leaving the marina after months of refit work, everything that had been stripped off Paikea and put into storage to make space for the project had to go back on — and this was the moment to actually understand what “back on” meant in real numbers. Sea trials had put the boat at roughly 8.8 tonnes on the crane. That became the working baseline: whatever gets loaded back on needs to be weighed against that number, honestly, item by item.
Not everything that came off deserves to go back on
A lot of what had accumulated aboard over the years wasn’t really needed — inherited spares from a previous owner, several of which turned out to be broken parts kept as “spares” for other broken parts. Sixteen skin fittings existed on the original boat; four cover everything actually needed now that the systems and how the boat is really lived on are properly understood. Fewer penetrations through the hull means fewer places for something to eventually go wrong — a straightforward trade-off between convenience and long-term risk.
Some items are genuinely needed but not yet ready to install — carbon fibre jockey poles destined to become new dinghy davits, replacing the current stainless steel set, plus spreaders and brackets for a radar upgrade and solar panel components still waiting on their turn in the project queue. Until those upgrades happen, both the old hardware and its intended replacement have to travel together, adding real weight for a project that hasn’t happened yet. Resin, fibreglass, and carbon cloth for ongoing builds add more again. And three growing kids add their own weight to the equation — a boat isn’t just cargo, it’s a home.
Why 350 kilos of “stuff” matters more than it sounds like it should
The final tally, once everything genuinely necessary was weighed and logged, came to 350 kilos — more than anyone on board guessed, despite everyone having placed a bet on the number beforehand. On its own, 350 kilos doesn’t sound dramatic. In context, it is: filling and draining the boat’s 500-litre water tank alone shifts bow trim by 40 millimetres, which gives a real sense of just how sensitive this hull shape is to added weight. Three hundred and fifty kilos of gear, stacked on top of that same sensitivity, pushes the boat down further still — and because most of that gear has to be stored forward for lack of anywhere else, it’s adding weight in exactly the position that matters most for wing deck clearance.
Why skinny hulls make this worse, not better
Paikea’s hull shape is a genuine double-edged sword. Slim hulls are fast — that’s precisely why this era of catamaran was built this way — but slim hulls also sink deeper and faster under the same added weight than a wider, more voluminous hull would. A production catamaran with fuller hulls might absorb 350 kilos and barely show it in the waterline. On a boat built for speed over payload, the same weight has an outsized, measurable effect.
That effect shows up directly as wing deck slamming. Every catamaran’s wing deck contacts the water in the right conditions — any claim otherwise means the boat hasn’t actually been sailed offshore yet. What weight changes isn’t whether it happens, but how often and how hard. Losing 40 millimetres of wing deck clearance can mean the difference between every fourth wave making contact and every third — a real, felt difference in comfort for a family living aboard full-time, not an abstract number on a spec sheet.
The real danger: righting moment, not the wing deck
Wing deck slamming is uncomfortable. A far more serious consequence of added weight is the change in righting moment — how much force it takes to knock the boat over. Counterintuitively, a heavier catamaran is often described as “safer” because it resists heeling more. In practice, that’s not the safety margin it sounds like.
There’s a real sweet spot in catamaran weight. Too light, and a boat becomes twitchy under a gust — hulls fly, and capsize risk climbs, the way it does on a stripped-out race boat. Too heavy, and the opposite failure mode takes over: a gust hits, the hull barely lifts at all, and instead of the boat visibly reacting and giving a clear early warning to reduce sail, all that load transfers straight into the rig. That’s how rigs come down — not gradually, but suddenly, with the mast becoming the boat’s unintended structural fuse. Having actually worked in design offices where catamarans launched overweight without a corresponding rig upgrade, and watched exactly that scenario play out — rig ends up on the deck, not a hypothetical.
The right amount of weight lets a boat accelerate and heel slightly under a gust — enough to give clear, physical warning that it’s time to reduce sail, without ever putting the rig itself at risk. Four months spent building a carbon rig from scratch is not something anyone wants tested as a sacrificial fuse.
The downstream effects most people never connect to weight
An overloaded rig doesn’t fail in isolation. Every piece of hardware downstream — clutches, winches, padeyes, soft shackles, sails — wears out faster under load it was never sized for. Sails blow out when a gust overwhelms a boat that can’t accelerate to relieve the pressure. Rudders, stocks, tiller arms, and linkages all work harder recovering a heavier hull through every wave, which in turn drives the autopilot to work harder and draw more power — a genuine downward spiral where one overlooked kilogram eventually shows up as increased electrical draw three systems removed from where the problem started.
Most modern production catamarans — Fountaine Pajot, Lagoon, Leopard — publish an optimal design weight precisely because everything on the boat, every safety factor, every structural margin, is calculated against that number. Exceed it, and those margins quietly disappear, whether or not anything visibly breaks right away. Paikea predates that level of accountability in catamaran design, making this kind of manual weighing and tracking even more important, not less.
A low-tech trim reference that actually works
Before splashing the boat, small countersunk marks were drilled into the hull at bow and stern — a simple visual reference for both waterline height and fore-aft trim, adapted directly from how race boats get measured and tracked against class rules. It’s a genuinely useful habit carried over from a very different world: a quick glance tells you immediately whether you’re loading too much weight too far forward, without needing to do any maths or squint at a wavy waterline trying to judge it by eye.
For a detailed description on how to do this see How to Make Waterline Markers
The Takeaway
None of this is really about chasing a number for its own sake. It’s about understanding that every kilogram brought aboard a lightweight-hulled boat has consequences that ripple outward — comfort, safety margin, rig loading, hardware life, even battery consumption — far beyond the simple question of whether it fits in a locker.