Ever since Robert Beebe published his transformational work Voyaging Under Power, boaters who are interested in a long-distance explorer yacht have followed a similar path. The consensus has been that the best boats for long-distance power cruising were heavy, displacement-speed monohulls.

Stephen Weatherley, the founder of Archipelago Yachts, has different ideas.

Two years ago, he began a search for a 45- to 60-foot explorer yacht with long range, good seakeeping characteristics and speeds in the upper teens to mid-20 knots. It was a combination of features, he came to realize, that virtually no current boat fully embodied. There were plenty of durable, high-speed boats capable of handling adverse conditions, but in the targeted size, they couldn’t carry enough fuel for his intentions. The closest Weatherley was able to get to his dream boat were a few semi-displacement explorer yachts, but they had speeds in the mid-teens, and high fuel consumption.

Believing he may have to build a custom boat, Weatherley took his quandary to the Chartwell Marine team of naval architects near his home in the South of England. They concluded that one of the limiting factors in Weatherley’s quest was restricting the search to monohull vessels. Chartwell has an extensive portfolio of rugged multihull vessels designed to service the North Sea energy industry. They knew that speed, seakeeping and range could coexist on a multihull platform.

Not only did Weatherley have no objections to a catamaran hull, but he also saw additional benefits. Catamarans offer a softer ride than a monohull, with a 30- to 50-percent lower rate of vertical acceleration in a head sea, meaning less slamming and hobbyhorsing over swells. The overall usable length of a catamaran is greater. Cats have a lower degree of heel in turns, and higher stability compared to monohulls. They also offer higher survivability if a hull is breached. All of these features are why nearly 70 percent of all high-speed passenger and vehicle ferries are catamarans.

With the help of naval architect Robin Saunders at Chartwell, Weatherley scaled down one of the firm’s multihull designs, creating a proof of concept and prototype of the Archipelago 47-foot explorer yacht. He also launched the company Archipelago Expedition Yachts to manufacture and market the boat.

Weatherley is encouraged that catamarans being built as cruising yachts are no longer just an interesting idea. They have arrived as an alternative to a monohull. Power cruising multihull boats are one of the fastest-growing segments of the recreational boating market. From multihull center-consoles to mid-size catamaran cruisers, and from large high-speed sport-fishing catamarans to luxury multihull motor yachts, the advantages of multihull vessels are being appreciated by a growing audience.

The Prototype in Action

Archipelago is located near Chartwell in Southampton, a historic shipbuilding location with access to fine craftsmen and to the Solent, the English Channel and the North Sea. I visited Archipelago during the Cowes Week Regattas. The day before I got aboard the 47, Weatherley had escorted some regatta racers to the starting line. Several race boats returned to port with crews sickened and rigging damaged from the Solent’s infamous short, steep seas. Weatherley was quite pleased with how well his prototype 47 effortlessly cut through the rough seas.

I got aboard in the yacht-friendly village of Hamble-le-Rice, with plans to cruise to Lymington. The morning greeted us with steady rain, dense fog and poor visibility—in other words, perfectly lovely English boating weather.

Visibility improved by the time we exited the River Hamble for a short run through Southampton’s waters, and out into the Solent. Weatherley increased the boat’s speed to a comfortable cruise of 18 knots. There was no perceptible change in the trim angle as the 450-hp Iveco diesels settled into 2300 rpm and the twin hulls sliced through the water. We burned 23 gallons per hour at a smooth 18 knots.

With 1,000 gallons of fuel, the Archipelago 47 has a reported range of 2,400 nautical miles at 8 knots, 1,400 nm at 10 knots, or 700 nm at 18 knots. It’s also rated CE Class A for extended ocean voyages. Archipelago offers multiple engine configurations, as well.

Cruising aboard the prototype has led Archipelago and the team at Chartwell to take numerous notes on improvements that will be implemented in the final product. A good example is a reconfigured helm. They’re also working on modifications to the stern to make boarding easier and to provide easier access to a tender.

The aft deck will be left open to accommodate the owner’s choice of exterior deck furniture. The salon is bright and open, with almost unlimited flexibility for how it can be used. Staterooms are typical of a catamaran, with a master taking up the port hull and an owner’s choice of a guest stateroom or a utility area in the starboard hull.

Access to the machinery spaces in each hull is through lifting hatches on the aft deck. All of the machinery and electrical components are thoughtfully arranged, securely mounted and easily accessible. The framing and welds on the aluminum construction look almost artistic in their precision and method of assembly.

In addition to the 47, Archipelago has designed a 40, 52 and 63, and currently has contracts to build one of each. The 52 comes with a flybridge, and the 63 is expected to have fuel-cell technology with globe-circling range. All the models have thick aluminum bottom plates and skegs beneath the propellers, allowing the boats to be beached on a falling tide.

Weatherley set out to build power catamarans to cross oceans with ease and economy. Based on what I saw in the prototype, he is close to achieving his goal. 

Rugged Inspiration

To be sure, there are well-built, displacement-hull trawlers exploring the world with happy owners. Archipelago Yachts founder Stephen Weatherley wants to add to that mix with explorer catamarans. He says the reason builders and boaters gravitated toward heavy-displacement models had more to do with range and stowage than with seakeeping. He’s instead taking his cues from the fleet of north sea pilot and rescue boats, which are lightweight, fast, planing hulls that regularly handle extreme conditions.

ARCHIPELAGO

LOA: 47ft.
Beam: 21ft.
Draft: 3ft. 3in.
Construction: aluminum
Displacement: 37,500 lbs.
Fuel: 1,000 gal.
Water: 264 gal.
Engine: 2x 450-hp Iveco NEF N67
Info: archipelago-yachts.co.uk

This article was originally published in the January/February 2024 issue.