T47 Explorer
THE BEST, MADE BETTER
The ultimate collaboration. Twisted Marine, based in Salcombe, UK, have taken the Archipelago 47, and re-engineered the boat from bow to stern. Available in select colourways, and with increased engine power, and a bespoke interior the T47 Explorer takes the best in class, and turns up the volume.
Twisted Marine are famous for taking high-performance craft and getting even more from them. In this collaboration, Twisted and Archipelago have joined forces to create the ultimate explorer vessel, but Twisted. The boat is every bit an Archipelago 47, but tailored, unique, and exceptional.
Stand out from the crowd
The Twisted T47 Explorer is available in four unique colour-ways. Each colour is distinctive, and not available on the standard Archipelago 47. Each T47 also features a hardened ultra tough matt-black roof, to store the toughest of expedition equipment. Each vessel is fitted with upgraded engines, and stern-gear to push the boat faster through more demanding environments.
T47 EXPLORER KEY FEATURES
ACCOMMODATION
Up to 30 knots
2023 PRICING
OTHER FEATURES
Ocean capable
A variety of propulsion options available (including hybrid and electric) depending on requirement
Highly flexible design service with customisation as standard
A selection of high-quality interior finishes
- Subscribe Now
- Digital Editions
Archipelago 47 yacht tour: On board the all-new ocean-crossing powercat
- Top stories
- yacht tours
Reporting from the 2022 Southampton Boat Show, MBY's Alex Smith takes us on a full tour of the Archipelago 47, which was making its global debut...
Designed in collaboration with commercial specialist, Chartwell Marine, this British-built, long-distance aluminium powercat is the first in the firm’s hotly anticipated explorer range and it’s refreshing for a variety of reasons.
For a start, the pronounced elevation of those hull sides creates two very handy benefits. Firstly, it drops the relative profile of the pilothouse, giving the Archipelago 47 a potent military aesthetic that makes the most of the raked roofline and the inverted screen.
And secondly, it creates some superb internal space, both in terms of the storage lockers at the aft ends of those side decks and the headroom for the cabins inside those hulls.
The aluminium construction is also very handy for a boat of this type. In addition to keeping the weight down, improving impact resistance and enabling much simpler repairs, it also makes custom upgrades much easier.
From the big aft deck to the central saloon and the cabins, it can all be tweaked in line with your needs – and so can that big expansive rooftop.
Article continues below…
Leen 72 first look: Cutting-edge trimaran launched by Neel Yachts
Leopard 46PC test drive: First full review of the world’s favourite powercat
While the show boat uses a huge rack for your toys, plus extra space that looks ideal for solar panels or a tender and crane, a flybridge version of the Archipelago 47 is also under development, which should prove exciting news if alfresco seating is a key priority.
That said, the existing layout feels great. With its wide-open space and pale, naturally textured oak fit-out, the main deck saloon is a thoroughly welcoming part of the boat.
The all-round views are great, thanks to the use of sailboat-style guardrails rather than solid bulwarks. And the galley is also a treat, courtesy of elevated work surfaces that enable you to stand rather than stoop as you prep your food and drink.
Down below, Archipelago has confined the accommodation solely to the hulls, avoiding a deep-chested bridge deck, which might threaten to compromise the boat’s running efficiency and ride softness.
But even on boat number 1, the calibre of those sleeping spaces is very clear to see. There’s an outrageously indulgent owner’s cabin in the port hull and there will be a pair of guest cabins, divided by a central heads to starboard, although they weren’t finished in time for the Southampton Boat Show .
You can also spec it with four cabins if required but in all cases, the vast hull windows and lofty side decks make this intriguing new cat a seriously attractive proposition for ambitious cruisers.
The elevated hull sides do good things both for the styling and the internal space
Capable of running at speeds of up to 30 knots, sleeping up to eight people in four separate cabins and cruising continuously for more than 3,000nm, the new Archipelago 47 is all about expanding your horizons.
While hybrid and electric boat options are likely to prove popular on production models, the first Archipelago 47 will be powered by twin 420hp Iveco diesels on straight shafts running in half tunnels.
As for the Archipelago’s aluminium construction, not only does that help keep the weight down, improve impact resistance and reduce development costs. It also makes custom models much easier to create and impromptu repairs much simpler to execute during remote off-grid adventures.
The Archipelago 47 is an aluminium cat with global ambitions
Company founder, owner and CEO Dr Steven Weatherley is a cyber security specialist with a PhD in astrophysics and an experienced motor boat owner.
After searching in vain for a fast, go-anywhere powercat to replace the family’s Mitchell 31, he decided to commission and build one of his own. He was so pleased with the concept drawings that he decided to turn it into a business.
A second Archipelago 47 is already in build and plans for 38ft and 56ft models are also being developed.
In the short term Weatherley plans to use his new boat for day trips and weekends in the Solent with his wife and four young children but ultimately has ambitions for more adventurous bluewater cruising – hence the range requirements.
“The march of the multihulls seems to be gathering pace with every month but this one really does it for me,” says MBY editor Hugo Andreae. “Small and fast enough for day trips but also robust and efficient enough to cross oceans, it really does seem to offer the best of both worlds.”
Archipelago 47 specifications
LOA: 47ft 7in (14.50m) Beam: 21ft 3in (6.50m) Engines: Twin 420hp Iveco diesels Top speed: 30 knots Starting price: £1,100,000 (inc. VAT)
Azimut 62 Fly First Look: Seting New Standards for Outdoor Entertaining
Arksen 65 first look: brand new british explorer yacht, new boats at southampton boat show: fairline targa 40, latest videos, princess s65 sea trial and tour: £2m sportsfly ticks all the boxes, watch: beneteau swift trawler 54 sea trial – £1.4m cruiser is the ultimate home, watch: parker sorrento sea trial: 50-knot cruiser with a killer aft cabin, watch: virtue v10 sea trial: €272k weekender.
New Archipelago 47 “Explorer’s Catamaran”
A new entry from the UK, Archipelago Expedition Yachts just unveiled its flagship 47-foot cruising catamaran that it says “offers the ultimate adventure.” The first yacht in a new Archipelago Range, the 47 is being built by Chartwell Marine on the Isle of Man. The range will include 38- and 56-foot yachts later on.
The Archipelago 47 is designed as an “explorer’s catamaran,” according to the company, with a combination of luxury, fuel efficiency, stability, ocean-going performance and even wheelchair access. Powered by two 420-hp Iveco diesels, the 47 is projected to have a top speed of 30 knots and a range of 3,000 nm.
Dr. Stephen Weatherley, the founder and managing director of Archipelago, says, “For this project we wanted to strike a balance between stability, speed, comfort, and sustainability – and, of course, plenty of style. If you’re looking for a vessel that’s as good for short getaways as it is for long journeys, the Archipelago 47 is for you.”
The yacht has four cabins, sleeping eight people. The interior design can be customized, and the boat is built to take hybrid electric-diesel drive, if the owner wants it. The large roof area has room for a solar array that could generate enough power to run the AC and house systems at anchor. It also is built for sustainability, with an aluminum hull, yielding lower environmental impact than fiberglass.
For a luxury touch, the salon and galley sole is heated, and the cat has a divider than can shut off the wheelhouse from the lighted salon for night cruising.
The high-low swim platform and extra wide door to the salon are built for wheelchair access, with one level all the way to the helm. There are also fixed points at the helm station so a wheelchair can be secure there.
Specs.: LOA: 47’5”; Beam: 21’3”; Draft: 3’9”; Disp.: 16 tons; Fuel: 528 gals.; Water: 264 gals..; Power: 2×420-hp Iveco diesels. Read more:
http://archipelago-yachts.co.uk
About Author
Related Posts
Seen at the Cannes Show: Marex of Norway Soon to Invade America
Outer Reef Yachts Announces Merger with Dutch Builder Lynx Yachts
Riviera Introduces New 6800 Sport Yacht Platinum Edition
Leave a reply cancel reply.
Save my name, email, and website in this browser for the next time I comment.
- The magazine
Current issue
- All the issues
- My magazines
- Technical specifications
- Multihull of the Year
- Classified Ads
- Destinations
- Online store
- All the magazines
- Subscriptions
- Accessories
Archipelago 47
Built in aluminum and with ocean passagemaking capabilities, this new powercat built in the UK is perfectly suited for expeditions and cruising far from the beaten track.
Create a notification for Multipower
We will keep you posted on new articles on this subject.
Published 19/01/2023
By Dick Sawyer
Published: jan. / feb. 2023
Choose the option that suits you best!
Issue #: 187
Published: January / February 2023
- Price per issue - digital : 6.20€ Digital magazine
- Price per issue - print : 10.90€ Print magazine
- Access to Multihulls World digital archives Digital archives
The builder has taken great care to combine robustness and comfort - the interior is fitted out with the greatest of care and is even equipped with an underfloor heating system, contrasting with the “utilitarian” appearance conjured up in large part by the forward windows whose slope is reversed. Another very “professional” detail is that the interior helm station can be blocked off, so a night watch can be properly maintained even with the lights remaining on in the saloon. Note the large trampolines up front, now a very atypical feature aboard a powercat. Our only one regret with the deck plan is that there are no footbraces (much less any sort of bulwark...) on the side decks. The nacelle remains very open to the cockpit - the latter, decked with synthetic teak and its after end becoming a neat aft platform. A large part of the coachroof is taken up by a roof rack, which is very practical for carrying kayaks or paddleboards for example. Generously powered (840 HP in total for a lightship displacement of 17 tons), the Archipelago 47 is capable of reaching a maximum speed of 25 knots. The builder also offers hybrid and electric propulsion systems and will soon be designing other models with the aim of creating a complete range. Builder: Archipelago Yachts Length: 47’5” (14.45 m) Beam: 21’3” (6.48 m) Draft: 3’9” (1.14 m) Light displacement: 37,475 lbs (17 t) Maximum speed: 25 knots Fuel: 528 US gal (2,000 l) Water: 264 US gal (1,000 l) Range: 3,000 nautical miles Engine: 2 x 420 HP Iveco Price: from £1,200,000 ex-tax
www.archipelago-yachts.co.uk
Tags :
- Power catamaran ,
- Archipelago 47 ,
- Archipelago Yachts
Most-read articles in the same category
Tricat 8.50
Lagoon Neo program
Les Occasions du Multicoque et du Refit
Dragonfly Days 2024
Bourgogne Catamaran
Rapido Trimarans
What readers think.
Post a comment
No comments to show.
Useful links
MW #197 - Oct / Nov 2024
T-2000 Voyager
70 Sunreef Power
Subscribe now
The latest news from €3 / month
Video of the month
Our latest YouTube hit!
The Multihull of the Year
The 2024 results
Classified ads
TRICAT 30 PERFORMANCE
TRIMARAN FARRIER F9AX
Privilege 515 (2010 - refit 2021) v. 3 cabins
Power catamaran Fountaine Pajot Greenland 34 - fully self-sufficient
Vous avez ajouté " " à vos favoris., vous avez supprimé " " de vos favoris., in order to add this article to your favorites, please sign in..
Boat Search
Contact Broker
Whether you’re buying or selling, let us put our knowledge and experience to work for you.
NEW LISTING - ARCHIPELAGO 47
Wednesday 1 Mar 2023
This is a unique opportunity to acquire the awe inspiring Archipelago 47 (ex-demonstrator) for the 2023 season. The ULTIMATE OFFSHORE EXPLORER catamaran. Bridging the gap between performance, range and luxury accommodation this aluminium constructed luxury power-cat is the ultimate long range explorer. With a range of 1,400 nautical miles the Archipelago gets you to remote location in true comfort, safety and style. Designed by Chartwell Marine of commercial Windfarm transfer vessel fame, this Archipelago 47 has been meticulously constructed in Cowes by the leading offshore commercial aluminium fabricators. Viewing is highly recommended. Hull No.1 of the Archipelago 47 (as photographed) is commissioned, and sea trials have been completed. As the company's demonstrator, this very boat is now immediately available to purchase at a significantly reduced price. The starboard hull can be fitted out to your requirements at no additional cost* You may decide to fit a VIP double cabin with bathroom or alternatively an office/schooling area with separate bunk cabin. The Archipelago 47 is a remarkable pocket explorer yacht and we look forward to working with you further. LOA: 14.5m (47'5") LWL: 14.5m (47'5") DRAFT: 1.0m (3'2") BEAM: 6.5m (21') DISPL: 17 tonnes (lightship) RANGE: 1,400 nm (displacement speed)
Yachting World
- Digital Edition
Jimmy Cornell: Why aluminium centreboarders are ideal for serious explorers
- Jimmy Cornell
- November 12, 2020
Having covered 100,000 miles in his aluminium centreboarders, Jimmy Cornell explains why he rates them so highly for adventure sailing
A true exploration yacht: Jimmy Cornell’s Ovni 43 Aventura III in Antarctica
Both Aventura III , an Ovni 43, and Aventura IV , a Garcia Exploration 45, were aluminium centreboarders. Having clocked some 100,000 miles with them, including passages to Antarctica and the North West Passage , I can state unequivocally that for safety as well as convenience, a centreboard is a great advantage on a cruising boat.
In my case, the choice of aluminium for a boat intended for exploring areas off the beaten track was logical, and so was that of a centreboard. One of the main reasons for the latter was to increase my cruising options. The ability to reduce draught instantly is also a safety factor, as it allows access to a protected shallow spot if needing shelter in an emergency. Also, with a flat bottom, the boat can dry out.
Another advantage is that the board can be used for sounding when entering an unfamiliar anchorage, a new meaning for the term ‘sounding board’. While in the North West Passage we hit an uncharted rock quite hard, but the centreboard did its job and swung up, scraped along the top of the rock, then dropped back into its lowered position. The only damage was to my ego, but any other boat would have been in serious trouble!
Both yachts have integral centreboards, so that when fully raised, the board retracts into the hull. The ballast is also internal, with a ratio to displacement of 32 in both cases, which is similar to that of most modern cruising yachts. This brings considerable performance advantages.
The main role of the board is to provide lift when sailing close-hauled, and to reduce leeway when reaching. With the board fully down Aventura III drew 2.4m, and, when trimmed properly, it could point as high, or almost as high, as most fixed keel cruising boats. With a draught of 2.8m with the board down, Aventura IV performed even better than her predecessor.
To take full advantage of this special feature, a centreboarder needs to be sailed quite differently, both on and off the wind. This is when the centreboard becomes a true asset as it allows the wetted surface to be reduced. The technique is to lift the board gradually as the apparent wind goes past 135°, and continue lifting it up to the point where the board is fully retracted. This is, for me, the greatest advantage as the risk of broaching is virtually eliminated.
Article continues below…
Zero-carbon cruiser: Jimmy Cornell explains his electric multihull project
In 2010 I sold my [Ovni 43] Aventura III and, as I was 70, I felt the time had come…
Allures 40.9 vs Ovni 400: French aluminium centreboarders go head-to-head
Back in the mid-2000s the niche market for aluminium centreboarders was disrupted by the arrival of a new upstart, Allures…
The absence of a keel to act as a pivot in a potential broaching situation means that the boat does not tend to round up when, in a similar situation, a fixed keeled boat would do just that. This has allowed me to keep the spinnaker up longer than I would have done otherwise.
With the board up, steering the boat in strong winds was easy, as there was no keel to act as a pivot if the person at the helm made a mistake, or a large wave forced the boat into a broach. With a flat bottom and no keel, Aventura III acted just like a large windsurfer, with the rudder having no difficulty keeping the boat on course. Aventura IV has twin rudders so tracked even better and was a joy to helm.
Alloy alternatives
If you are considering an aluminium centreboard, make sure to read our head-to-head test of the Allures 40.9 and Ovni 400 . If neither of those suit, you probably need to go up a level in size and price, to the more semi-custom options offered by shipyards such as Garcia, Boreal or even KM. It is pertinent, however, to note that many of these traditional monohull brands are now branching out into the multihull market too.
Photo: Morris Adant
Designed in collaboration with Jimmy Cornell to transit the North West Passage, this model set a new rugged standard for mid-size exploration yachts. In inclement weather, watchkeeping can be done from a completely protected position at the forward end of the cockpit, or from the helmstation inside the pilothouse.
Price: €498,000 (ex. VAT)
Boreal 44.2
Boreal is a brand born from the experience of Jean-François Eeman, who spent six years sailing around the world with his four children. The new 44.2 will replace the ten-year-old, award-winning, Boreal 44. It has the same interior as the 47.2 (pictured), but with a single helm and rudder and a more enclosed cockpit.
Price: €485,520 (ex. VAT)
Garcia Explocat 52
Garcia is maintaining its exploration focus with its first catamaran. Once again there is plenty of protection on offer. A hard-top runs almost back to the transom and there is a complete interior navigation station similar to Garcia’s monohulls. The Explocat also has a forward cockpit accessible from the saloon via a watertight door.
Price: €1,159,000 (ex. VAT)
Vaan is a new brand, which uses recycled and sustainable materials – its first 42ft R4 is due for launch in early 2021. The aluminium hulls are formed from drinks cans, road signs and window frames, it uses cork decks and the upholstery is made from bio fabrics. It’s offered with electric propulsion and an optional regeneration system.
Price: €399,000 (ex. VAT)
Allures & Ovni catamaran update
Plans to launch the first Allures multihull, the aluminium hulled and glassfibre decked C47.9 (above), have been put on hold due to the success of its sister company’s new Explocat 52.
Ovni’s multihull solution, meanwhile, is the Ovnicat 48, which has been on the drawing board for a couple of years but has yet to be built.
First published in the October 2020 issue of Yachting World.
- 47 Explorer
Twisted Marine have taken the Archipelago 47, and re-engineered the boat from bow to stern. Blending the sea-keeping prowess of a high-performance multihull commercial craft with an exciting new design to create an adventure-ready luxurious yacht.
The Twisted T47 sets the bar.
THE ADVENTURE JUST GOT
The T47’s sustainable aluminium twin-hull design creates an incredibly stable craft with ocean-going capabilities, providing a smoother ride and more comfortable living space for those once in a lifetime experiences. Performance and adventure are at the heart of the Twisted T47. With hybrid and customisable options available, the T47’s versatile design and long-range capabilities make the world your playground.
SPECIFICATION
Starting from 1150hp / 854kW
ACCOMMODATION
Up to 8 people
2023 PRICING
Starts at £1.75m
COMMISSIONED
The Twisted T47 offers a reconfigured interior and cockpit styling with a focus on improved ergonomics and technology enhancements . The multihull design sleeps 8 in style with a full height en-suite in each cabin. The rear deck space creates an integrated social space while doubling up as a utilitarian working platform for those hardened Artic Circle adventures.
One of our experts will be delighted to answer any questions you may have. So please get in touch…
Made in Salcombe
2022 © twisted marine
Terms & Conditions . Privacy
Let's Talk Twisted
Phone: +44 (0) 1845 574 990
or enter your details below...
COMMENTS
THE ULTIMATE EXPLORER CATAMARAN. is the 47 foot (14.5m) ocean-capable Archipelago 47. Bridging the gap between performance, range and luxury accommodation, the Archipelago 47 offers the ultimate adventure. Born from the highest quality design and engineering, the Archipelago forty-seven offers ultimate performance, functionality and comfort.
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.
Twisted Marine, based in Salcombe, UK, have taken the Archipelago 47, and re-engineered the boat from bow to stern. Available in select colourways, and with increased engine power, and a bespoke interior the T47 Explorer takes the best in class, and turns up the volume. Twisted Marine are famous for taking high-performance craft and getting ...
The Archipelago 47 is the first yacht from Archipelago Expedition Yachts. The vessel is a hugely capable explorer yacht with a range of up to 3000 miles, and...
This stylish aluminium adventure cat can cope with anything from short blasts to long distance cruises. Alex Smith puts the Archipelago 47 through its paces....
A fascinating aluminium explorer catamaran, the Archipelago 47.Sponsored by: https://www.boatsandyachtswarranty.com In association with:https://www.yacht-sol...
Archipelago 47 specifications. LOA: 47ft 7in (14.50m) Beam: 21ft 3in (6.50m) Engines: Twin 420hp Iveco diesels. Top speed: 30 knots. Starting price: £1,100,000 (inc. VAT) Reporting from the 2022 Southampton Boat Show, MBY's Alex Smith takes us on a full tour of the Archipelago 47, which was making its global debut...
The Archipelago 47 is designed as an "explorer's catamaran," according to the company, with a combination of luxury, fuel efficiency, stability, ocean-going performance and even wheelchair access. Powered by two 420-hp Iveco diesels, the 47 is projected to have a top speed of 30 knots and a range of 3,000 nm.
The all-aluminum catamaran is reportedly capable of reaching speeds up to 25 knots, with a leggy range of over 3,000 nautical miles at displacement speeds. ... which was designed as more of a midrange explorer. Archipelago 47. LOA: 47ft. Beam: 21ft. Draft: 3ft. 3in. Construction: aluminum . Displacement: 37,500 lbs. Fuel: 530 gal. Water: 264 ...
Meet the Archipelago 47. An aluminum catamaran with twin 450-hp FPT diesels, the Archipelago 47 is built for just about everything you can throw at her. With a maximum range of 3,000 nm at displacement speed and a cruising speed of 25 knots, she's designed to cross the ocean or enjoy for a day trip just about anywhere on the planet.
Generously powered (840 HP in total for a lightship displacement of 17 tons), the Archipelago 47 is capable of reaching a maximum speed of 25 knots. The builder also offers hybrid and electric propulsion systems and will soon be designing other models with the aim of creating a complete range. Builder: Archipelago Yachts Length: 47'5" (14.45 m)
Description. Archipelago 47. Please contact Ben Oaksmith for more info at [email protected]; 206.949.2270. The Ultimate Explorer Catamaran is the 47 foot (14.5m) ocean-capable, category A rated Archipelago 47. Bridging the gap between performance, range and luxury accommodation, the Archipelago 47 offers the ultimate adventure.
Reporting from the 2022 Southampton Boat Show, MBY's Alex Smith takes us on a full tour of the Archipelago 47, which was making its global debut...Sponsored ...
Yacht for sale is a 2022 CUSTOM 47' 7" "ARCHIPELAGO 47 (available now)" Archipelago 47 Explorer Catamaran Motor Yacht in Southampton, England, United Kingdom. Archipelago 47 (ex-demo) Launched Autumn 2022. Aluminium fast explorer by Chartwell Marine - designers of the leading Offshore windfarm support vessels This is a go anywhere rugged ...
The Archipelago 47 is a remarkable pocket explorer yacht and we look forward to working with you further. LOA: 14.5m (47'5") LWL: 14.5m (47'5") DRAFT: 1.0m (3'2") ... (ex-demonstrator) for the 2023 season. The ULTIMATE OFFSHORE EXPLORER catamaran. Bridging the gap between performance, range and luxury accommodation this aluminium constructed ...
2024 Sea-Doo Switch Compact. US$22,899. Performance East Inc | Goldsboro, North Carolina. <. 1. >. * Price displayed is based on today's currency conversion rate of the listed sales price. Boats Group does not guarantee the accuracy of conversion rates and rates may differ than those provided by financial institutions at the time of transaction.
Having covered 100,000 miles in his aluminium centreboarders, Jimmy Cornell explains why he rates them so highly for adventure sailing. Both Aventura III, an Ovni 43, and Aventura IV, a Garcia ...
Twisted Marine have taken the Archipelago 47, and re-engineered the boat from bow to stern. Blending the sea-keeping prowess of a high-performance multihull commercial craft with an exciting new design to create an adventure-ready luxurious yacht. The Twisted T47 sets the bar.
There are presently 4 yachts for sale on YachtWorld for Ocean Explorer Catamarans. This assortment encompasses 3 brand-new vessels and 1 pre-owned yachts, all of which are listed by knowledgeable yacht brokers predominantly in Finland and Maldives. Models currently listed on YachtWorld range in size and length from 61 feet to 79 feet.
Join me in this video as I spend the afternoon at sea on hull number one of the brand-new Archipelago 47 power catamaran with Steven Weatherley, the owner of...
The largest aluminium sailing catamaran in the world with a total length of 47m, an exceptional beam of 17.30m and an impressive all-carbon sail plan with a 55m mast. Project managed by the Owners Team and Design by Axel de Beaufort and naval architecture by Axel de Beaufort and Guillaume Verdier. She is a true sailing museum, first and only of ...
In this video, we will look at the build progress of hull number one of Archipelago 47, an explorer catamaran that offers a range of 3,000 nautical miles and...
Bartlesville, OK. $250. Chainsaw. Strang, OK. $1,700. 2016 John Deere Z345m zero turn 42" mower. Pryor, OK. 2023 Explorer catamaran 47 The ultimate power multi hull for any latitude. They are built on the design of North Sea supply vessels.