Here is the problem with buying a 78-foot yacht: almost every one of them tells you where you can go. Draft decides the anchorage, the anchorage decides the day, and you end up watching the good beach from half a mile out. The Lagoon Seventy 8 was built to break that chain. She is 78'1" long with a 36'1" beam - and she draws 4'2".
That number is the whole argument. It means a yacht with three to six cabins, a full flybridge and crew quarters can tuck into water that would stop most 50-footers, and it is why the Seventy 8 still commands attention on the brokerage market. Lagoon has since moved the large power catamaran flagship role to the Eighty 3 and placed the Seventy 8 in its Heritage line, which makes her a mature, proven design available to buyers who would otherwise be waiting on a build slot.
Who the Seventy 8 Is For
This is a boat for someone who has already learned what they want from time aboard. Lagoon's own framing is that space and privacy naturally go together on this yacht, and that she has the autonomy to make longer passages with peace of mind - which is a fair description of the buyer too. You are planning weeks, not weekends, and you are bringing people.
The layout supports either owner-operation with occasional crew or a full-time captain and chef. Both work, and the boat has dedicated crew accommodation for the second case. Be honest with yourself about which one you are before you choose a galley position, because that decision follows from it.
Layout and Accommodation
Lagoon built the Seventy 8 with three galley arrangements - aft galley, galley up, and forward galley - across cabin counts from three to six. The three- and four-cabin plans are the ones private owners gravitate toward, because they convert the reclaimed hull volume into stowage and larger cabins rather than more berths. The five- and six-cabin versions exist for owners who genuinely host large groups or run the boat commercially.
The owner's suite is the design's signature move. Lagoon integrated a transom into the coaming so the suite opens onto a private, uninterrupted view of the sea - the ultimate privilege, in the builder's words, and the feature nobody else on board has access to. Guest cabins carry their own heads and hanging stowage, with natural light from the hull glazing.
Deck and Living Spaces
The flybridge is where the Seventy 8 spends its life. The helm adjoins the lounging space rather than sitting apart from it, and Lagoon treats the whole level as an additional living deck rather than a driving station with seats. You can specify it standard, with sun baths, with loose furniture for a deck you rearrange to suit the evening, or with a jacuzzi.
Below that, the choices continue: a sundeck can be specified on the cockpit, and the saloon carries contemporary furnishings, refined woodwork and panoramic glazing that keeps the view continuous from the helm down to the water. Lagoon's stated ambition for the interior was timeless elegance, and the boat has aged in a way that supports the claim - a Seventy 8 built several years ago does not read as dated today.
Cruising Character
Twin Volvo D11-510 diesels of 510 HP each drive the Seventy 8 to a maximum of 19 knots, with a 10-knot cruise. A 580 HP option was offered, so check which engines are in the hull you are looking at. The 19-knot top end is genuinely useful - it is enough to reposition ahead of weather or shorten a delivery leg - but the boat is designed to live at 10 knots, where the wide beam and twin hulls give a flat, stable ride that does not tire people out over a long day.
She carries 2,246 gallons of fuel, which is what Lagoon means when they describe her autonomy for longer passages. Distance between fuel stops depends entirely on your speed, load and conditions, so use the sea trial on the specific boat rather than any generic figure.
The 4'2" draft remains the standout. It puts genuinely shallow cruising grounds within reach of a 78-foot yacht, and it changes anchoring from a compromise into a choice. Lagoon publishes an air draft of 29'4" (8.95 m), which is the number to check against fixed bridges on any inside route. She holds CE Category A offshore certification for 14 people.
Specifications
| Specification | Detail |
|---|---|
| Overall Length | 78'1" (23.80 m) |
| Beam | 36'1" (11.00 m) |
| Draft | 4'2" (1.27 m) |
| Displacement (Unladen) | 137,127 lbs (62,200 kg) |
| Engines | Twin Volvo D11-510 (2 x 510 HP) |
| Max Speed | 19 knots |
| Cruise Speed | 10 knots |
| Fuel Capacity | 2,246 gal (8,500 L) |
| Water Capacity | 423 gal (1,600 L) |
| Cabins / Heads | 3-6 Cabins / 3-6 Heads + Crew |
Recognition
The Seventy 8 was well received when she launched and the awards reflect it: multihull-of-the-year honours in both the motor-multihull and power-catamaran categories, collected on two continents across 2017 and 2018.
Living With the Boat
Handling is the honest conversation. The Seventy 8 is predictable rather than nimble - 62 tonnes and 36'1" of beam do not change direction on a whim - and while twin engines give you excellent low-speed control, this is not a boat to bring into a tight slip single-handed on a windy afternoon. If you plan to run her yourself, get real time at the helm with a professional before you take delivery, and plan on a second competent pair of hands for lines.
The beam is the practical gate on where she lives. Thirty-six feet one inch needs an end tie, a T-head, or a megayacht berth, and that should be confirmed in your home port before anything else. Against that, the shoal draft makes hauling and yard access simpler than it would be for a deep-draft yacht her length.
Maintenance follows catamaran logic: two of everything, in two separate and accessible machinery spaces. The duplication means more service items on the schedule, but the access is far better than a comparable monohull, and a failure in one hull leaves you with a working engine in the other.
Honest Trade-Offs
Buying into the Heritage line means brokerage buying, and on a boat with this many configuration choices the individual hull is everything - engine option, galley position, cabin count, flybridge specification. Two Seventy 8s can be meaningfully different yachts. Inspect accordingly.
Ten knots of cruise means passages are measured in days, and the tall superstructure means she carries windage at anchor that deserves respect in the ground tackle. The six-cabin version, while offered, gives up stowage that a long-distance owner will want back.
Weigh that against what you get: a 78-foot yacht with a 4'2" draft, an owner's suite with a private line of sight to the water, a flybridge that functions as a full living deck, offshore Category A certification, and a design that collected multihull-of-the-year honours on two continents. That combination is still rare, and the Seventy 8 delivers it as a settled, proven boat rather than a first-of-class experiment.