Design
FEA map showing structural stress distribution across the hull and deck under simulated load conditions
The PB72’s RMFoils require a precise insertion point through the deck
About Morrelli & Melvin Engineeering
Morrelli &Melvin Design and Engineering is a renowned naval architecture and engineering firmbased in California, specialising in the design of high-performancemultihull and monohull vessels. Founded by Gino Morrelli and PeteMelvin, the firmis globally recognised for its innovative approach to yacht and powerboat design – particularly in hydrofoil technology, advanced composite construction and high-speed performance systems. Over the years, Morrelli & Melvin
has been a key contributor to groundbreaking projects ranging from America’s Cup campaigns to record- setting offshore racing yachts. Their expertise spans the full spectrum of design and engineering: from concept development and structural analysis to performance optimisation and production support. Ferdinand van West, a naval
architect and partner at the firm, has been with Morrelli & Melvin for over a decade. He has played a leading role in many of the firm’s most ambitious projects, from project-managing the introduction of the Olympic Nacra 17 class to co-leading foil design for American Magic in the 37th America’s Cup. Ferdinand brings a unique blend of design, engineering, and on-the- water racing experience. He is also a well-accomplished sailor, most notably having won two world championships in the Formula 18 catamaran. His multifaceted expertise ensures that Morrelli & Melvin remains at the forefront of high-performance yacht innovation.
Principal dimensions of the PB72
• Length overall (LOA): 21.95m • Beam overall (BOA): 9.50m • Air draught: 37.00m • Light displacement: 20,500kg • Sail plan: Mainsail – 220m², J3 – 95m²
80 SEAHORSE
A: Displacement sailing (Red Arrow), with RMFoil retracted. B: Upwind semi-foiling with 80% lift fraction. C: Downwind semi-foiling with MH0, 80% lift fraction, windward hull flying. D: Downwind semi-foiling with MH0, 80% lift fraction, windward hull skimming the water, leeward hull lifted clear.
delivery trips. In light air or big breeze, the skipper has options: traditional sailing or full foiling and everything in between.
The interior challenge Below decks, we faced one of the project’s more complex design challenges: integrating a high-performance foil system into a refined, ergonomic interior that could meet the owner's high expectations for comfort and style. While our primary focus was on the structural layout, we later brought Design Unlimited on board - not only to optimise functionality but also to deliver a sleek, modern aesthetic that elevates the entire experience. The RMFoil cases, where critical load
maximum beam limits for docking. This complexity meant that the interior
‘Precise spatial planning was essential both above and below the deck’
paths converge, had to traverse living spaces without compromising structural integrity or usability. Unlike centerline daggerboards, which can be discreetly tucked away, these outboard foils extend diagonally through the hulls. Precise spatial planning is essential both above and below deck. The rondure (foil curvature in the front view), in particular, had to satisfy strict clearances for sailing operations in all modes while staying within the yacht’s
layout couldn’t be finalised until the design geometry was fully resolved. Bulkheads, cabinetry, passageways – even window placements – were sculpted around the foil trunks. All details had to accommodate both the static structure and the dynamic movement of the foils without disrupting ergonomics. The owner’s passion for interior comfort drove us to go further: he envisioned a galley that was as much a performance workspace as it was a place for relaxation. It even features a beer tap - an offbeat touch
that brings a bit of levity to serious offshore sailing. The cabins uphold this high standard as
well, being fully equipped and fitted with air conditioning to ensure luxury comfort during long passages offshore. Through careful design iterations and digital mockups, we achieved an interior that not only meets rigorous performance criteria but also delivers a distinctly stylish and inviting environment. It’s one of the most integrated and thoughtfully styled interiors that we’ve ever delivered on a high-
A
B
C
D
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148 |
Page 149 |
Page 150
