Engineering Paikea’s Rig: Adapting America’s Cup Technology for Cruising
April 2023
Taking an IACC mast and making it work on a cruising catamaran isn’t a matter of cutting it to length and stepping it. Every system on the original rig was designed for a grand prix racing programme with a full crew, unlimited budget, and a single regatta as the objective. None of that applies to Paikea. So every decision — rotate or fix, spreaders or lowers, where the winch goes, how the jib halyard works — had to be thought through from scratch.
This is how those decisions got made.
Rotate or Fix
The first question with a mast this size is whether to make it rotating. The answer isn’t obvious — plenty of performance cruising catamarans run fixed carbon rigs without problems — and Shayne thought hard about it in both directions.
The practical case for rotating came down to two things. First, the chord dimension on this section is large. When the sail isn’t up, there’s a significant amount of carbon facing into the wind. In a 50-knot anchorage, that’s real load on the anchor chain and real stress on the rig. Being able to feather the mast eliminates that problem entirely. Second, and more importantly for offshore sailing, it gives you control. If something goes wrong and you need to reduce load on the rig in a hurry, being able to rotate the mast to reduce its presented area is a meaningful safety tool.
The ball and socket arrangement at the base made rotating straightforward to engineer. To make it non-rotating would have required one additional fitting — a locking tang at the front of the mast ball with a receiving socket inside the mast foot. Simple enough. But with the ball already there and the case for rotating being strong, that fitting never got made.
A useful check on the decision: Shayne did a deflection test before committing to a spreaderless setup. They propped the mast horizontally, supported at each end, and hung weight off the middle to measure how much it bent. The answer was: not much. The fore-aft stiffness of this section is high enough that spreaders aren’t structurally necessary. That stiffness is also what makes a rotating rig viable — a flexible mast that’s rotating under sail load is a different engineering problem entirely.
The Rotation Spanner
Once the decision to rotate was made, the next problem was how to control it. A standard spanner arm out the front wasn’t going to work. The rotation lines would have nowhere logical to go, the arm would catch everything and everyone moving on deck, and it would interfere with the lockers. Out the back wasn’t possible either — windows and hatches in the way, same problem getting the lines back to the cockpit.
The solution was the wing arms either side of the mast — what Shayne calls the rotation spanner. They’re not just rotation control. They’re also steps, which solves another problem that existed on the previous rig: getting from deck level up onto the coachroof. The wings provide a solid, non-skid step on each side. Shayne says even if the mast were fixed he’d put them back on — they’re that useful.
The halyards park on the rotation lines on each side, masthead halyard on one side and fractional on the other. The inner attachment points on the wings turned out to be too close to the mast for parking halyards cleanly — too much slap — so the outer positions on the rotation lines are used instead. The inner forestay halyard wraps tight enough around the mast that it doesn’t cause problems.
One upgrade still to come: a centre pulling point on the cabin top. At high rotation angles the geometry of the spanner arm means the pull from the rotation line starts working backwards rather than rotating — you lose mechanical advantage exactly when you need it most. A fixed attachment point on the centreline of the cabin top will fix that. It’s planned, not done.
Spreaders or Lowers
The spreader question was heavily debated. In the end Shayne went with lowers — two sidestays running from the hounds straight down to the chainplates, no spreaders, no diamonds.
The structural case for lowers is the fore-aft stiffness of the tube. Spreaders exist primarily to give width at height, increasing the shroud angle and reducing compression loads in the mast. They also provide a place to attach checkstays and intermediates for controlling pre-bend. On a section this stiff, the requirement for pre-bend control at the lower panel just isn’t there. The tube doesn’t need it and adding spreaders would have meant more laminating, more fittings, more complexity aloft for no structural gain.
The aerodynamic case for lowers is the drag reduction. The original rig had a double diamond setup — two diamond arrangements, one in the lower third and one in the upper third, involving six wires total. Six wires create six drag sources. The new setup has two sidestays, two lowers, the forestay, and the halyards when they’re parked out of the way. The difference in drag is significant and measurable. The most noticeable place you see it is at anchor in wind: the load on the anchor chain dropped noticeably when the spreader rigging came off. That’s drag being eliminated, not just theoretical efficiency.
Weight savings were a secondary consideration. Shayne came in about 50kg lighter than the spreader setup — worth having, but not the primary driver.
Paikea’s old aluminium mast and the new carbon fiber rotating wing mast side by side in the yard. You can see how much more sleek and aerodynamic the new mast will be.
Winch on the Mast
The Barlow 24 winch from the original Cup rig is mounted on the mast rather than back at the cockpit, and the reasoning is straightforward once you think about how the boat is actually sailed.
Anything involving the spinnakers, code sails, or the jib gets handled from the mast area. If you’re hoisting a kite at nine at night, short-handed, kids asleep, you don’t want to be running back and forth between the mast and the cockpit. Having the winch at the mast means everything happens in the same place — hoist from here, control from here, drop from here. When dropping a sail, Shayne can have the halyard on the winch unclutched, control the rope by hand on the trampoline, watch the sail coming down, and manage everything at once. You can’t do that if the winch is twenty feet away in the cockpit.
The reefing and furling lines are different. Those go back to the cockpit because reefing and furling happen from the cockpit — that’s where you are when conditions are changing and you need to reduce sail. Day-to-day running of the boat happens there. So the split is logical: everything that requires you to be forward goes at the mast, everything that happens from the cockpit goes to the cockpit.
The staysail halyard is the one exception — it’s forward at the mast and has to be hoisted from there. But once it’s up and locked off, the sheets and furling line all run back to the cockpit, so you only have to go forward once.
The Jib Halyard System
The jib halyard doesn’t work the way you’d expect, and it’s worth understanding why.
There’s no dedicated jib halyard clutch or winch at the mast base. Instead, the halyard ends in a snap shackle attached to a short dyneema tail, which lashes to the tack fitting at the furler. To tension the luff, you hoist the sail to height, lock it off, and then tension the luff from the bottom using the lashing at the furler rather than from the top using the halyard. To release, you pull the ring on the snap shackle, the halyard drops free, and you lower the sail.
The obvious question is what happens if the jib needs to come down in an emergency — ripped sail, fouled furler, something going wrong at sea. Shayne’s answer is that in practice, modern furling jibs are reliable enough that a catastrophic emergency drop is genuinely rare. The luff tape almost always survives even when the sail doesn’t. If the worst happens, you pull the trigger on the snap shackle and deal with the consequences — it adds time, but the probability of needing it is low enough that carrying the complexity of a full clutch and winch system at the mast base isn’t justified.
This is the kind of decision that experienced offshore sailors make and beginners find alarming. The logic is sound: design for what actually happens, not for the theoretical worst case that rarely does.
Clutches and Locks
The mast runs nine clutches in the cockpit bank and they’re all accounted for. Shayne was deliberate about what gets a clutch and what doesn’t.
Loose luff sails — spinnakers, code zeros without cables — don’t get clutches at the mast. The reason is failure mode. A loose luff sail that partially destroys itself while flying is held together by its luff tape. Getting it off a clutch under those conditions means pulling up to release and then pulling down to extract from the lock mechanism, which is genuinely difficult when the sail is flogging and the load is high. Without a clutch, you run forward and release — faster and simpler in the situation where speed matters most.
Cable luff sails are different. A code zero or A3 on a cable can be clutched and then tensioned from below with a purchase system, the same way the staysail works. Shayne hasn’t set the deck up for that yet on Paikea, but the logic of when to use clutches and when not to is clear.
The staysail itself is on a lock at the mast — it goes up, gets locked off at height, and stays there. The sheets and furling line run back to the cockpit. It’s a cable luff sail on a system designed for it, so the clutch is appropriate.
The Wind Instruments
Two masthead wind units. The question answers itself once you understand how Paikea is sailed.
The autopilot runs on wind vane mode — always. The boat is sailed to the wind angle, not a compass heading, which means the wind instruments aren’t a nice-to-have, they’re the primary navigation input for the autopilot. Redundancy isn’t optional.
The upper unit is a tall carbon wand — a recycled vertical carbon unit that Shayne stripped down, extended the wiring on, fitted a new BnG sensor to, and remounted. Getting a working sensor onto a salvaged carbon wand involved pulling the original unit apart, cutting the wires, joining and sealing the extension, and reassembling everything so it was weatherproof. The result is the tallest thing on the rig and, in Shayne’s words, the crown and glory of the whole build.
The height matters for a specific reason. Running deep downwind, the lower wind unit gets blanketed — partly shadowed by the mainsail and partially affected by the upwash coming off it. The upper unit, sitting above all of that in clean air, reads the true wind angle regardless of what the sail plan is doing below it. For autopilot accuracy on downwind passages, that’s not a detail — it’s the whole point.
What Comes Next
The rig has been sailing since 2021. The masthead position is something Shayne would change — he’d bring it down to the orange band to reduce the lever arm when the code zero is fully loaded — but that’s a future modification. The centre pulling point for the rotation spanner is also planned. The lowers need attention — the chainplates have had some work and need to be right before the rig is tuned properly.
The build diary — the footage from the shed in Valencia showing the actual fabrication process, the decisions that got made in real time, the things that didn’t go perfectly and how they got sorted — is in the members hub. There’s a lot that didn’t make it into the public videos, both because we lost footage when a hard drive died and because some of the detail belongs behind the paywall.
The full mast story is on our free cornerstone page: Paikea’s Carbon Mast: The Full Story
For the build diary and the engineering detail that goes deeper than this: Youngbarnacles Members Hub