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Powerboat Design and Performance

By dag pike.

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9781472965417

Bloomsbury Publishing

31 October 2019

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All about powerboats : understanding design and performance

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Professional BoatBuilder Magazine

Cfd for powerboat design, part 2.

By Clay Ratcliffe , Jul 20, 2021

Computational fluid dynamics (CFD) modeling of the aerodynamics of a Doug Wright Designs 32′ (9.75m) high-speed catamaran revealed that while it ran at 100 mph, air compressed between the hulls, deck, and water was creating a backflow high in the tunnel and leaking out the front to mix with the airflow over the deck.

CFD analysis of hull aerodynamics holds the potential to answer many performance questions, including the cause of an infamous side-by-side blow-over of identical high-performance catamarans during competition in Key West in 2019.

In Part 1 of our series “ Accommodating Higher Power ” (Professional BoatBuilder No. 191) we explored a case study of hull refinement and the practical application of recent advances in computer modeling to the art and science of hydrodynamics. Looking back at the traditions of modern boat manufacturing, we delved into bottom design, old-school versus new-school tooling methods, and learned how builders can update trusted hulls with improved running surfaces.

Here in Part 2 we’ll look at aero­dynamics—making improvements above the waterline. —Ed.

Eighty percent of the surface of a standard high-performance monohull or catamaran is out of the water, running through air. I remember as a kid putting my arm out the rear window of our car, twisting my hand right and left, and feeling lift and downforce for the first time. We all have experienced that exercise, and the aerodynamic laws we learned as kids hold true with any object surrounded by air. As boat designers and builders, how much attention do we give to that 80% of the hull surface, and how important is it?

Our Part 1 hydrodynamics case study vessel was a 32 ‘ (9.75m) Doug Wright Designs open-cockpit catamaran. We performed what CAD designers call reverse engineering. We started with an object in completed form, but we didn’t have modern triangulated point-to-point computerized coordinates to form a CAD file. Thus, with the aid of FARO Technologies (Lake Mary, Florida) we scanned the entire vessel to an accuracy of 0.004 “ (0.1mm). Then, with the help of Dimensional Engineering (Houston, Texas), we transformed the raw data into a full-mesh watertight stereolithography (STL) file suitable for the next step: computational fluid dynamics (CFD) modeling of the hull’s hydrodynamics and aerodynamics.

When these boats are flying, as they frequently do during competition, tunnel pressure is released but must be quickly and smoothly reestablished when the boat recontacts the water. The risks are that while airborne the boats will either catch too much air and flip over backward or bury the bow when they land right-side up.

See the Air

Before working in performance boats, I was in auto racing and a fan of Dale Earnhardt. He often said he could “see the air” as he entered the corner. I remember watching him come in from the first 100 miles (161 km) of a Super Speedway at Talladega slouched down in the seat, five-point harness loosened, his hands loosely grasping two rungs of the steering wheel. He asked for 1.5 lbs (1.5 psi/0.1 bar) in the right-side tires and half a turn on the left rear suspension. He was conducting seat-of-the-pants “tuning,” because he could see (and feel) the air and the dynamics it had on an object slicing through it at 200 mph (322 kmh) on the back straight. Granted, in a boat we are aware not only of primary forces coming from the right and the left like a race car on a twisty high-speed road course but also oncoming waves, quartering seas, winds from all directions, and shifting loads that can move the center of gravity. But with 80% of the boat’s surface area in the air, let’s look at how we can “see” the air and modify it to enhance boat performance, efficiency, and safety.

From a camera’s point of view at the water’s surface it is easy to see that when traveling at speed, a high-performance catamaran is barely in the water. The weight supported by the water is close to zero, meaning the boat is actually “flying” on a cushion of air.

Headwinds and turbulent wave structures launch the high-speed catamaran and make it airborne often more than 50% of its operational duty cycle. Once the vessel launches, all the hydrodynamic hull design we refined in Part 1 is of little consequence until the next impact with the water. With engines mounted at the aft extremity of the boat momentarily unsupported by water, the stern drops, the bow rises, and the boat becomes an airplane in stall mode without the benefit of wings, ailerons, flaps, or other controls. If it doesn’t flip over backward, it then crashes back into the water transom first, tripping, and then risking stuffing the bow torpedo fashion in the wave ahead of it.

Key West World Championships

This simultaneous side-by-side blow-over during competition got the attention of the crowd and led driver Scott Porta, who was racing just ahead of the accident, to pursue CFD analysis of the dynamics between the two boats running at speed.

During the last Race World Offshore World Championships in Key West (November 6, 2019), an unexpected and unfortunate incident occurred in the Super Stock class race. Boat owners Bill Allen (Allen Lawn Care Race Team) and Loren Peters (Loren Peters Racing) were running side by side in two equally designed Doug Wright 32 ‘ race-prepared catamarans when they simultaneously flipped 180°, bow over stern. The accidental “blow-over” appeared to be choreographed. Fortunately, no one was injured, but many on the race course that day wondered how two boats running side by side could instantly go from running on a horizontal plane to vertical and then back to horizontal in a split second.

For the drivers, the experience was unbelievably fast and nearly indecipherable as far as aerodynamic analysis goes. Bill Allen (owner/throttleman, Allen Lawn Care Racing) recalled it like this: “I was a little short on room, and I don’t know if they didn’t know I was there or what…. I think, you know, that we got together, and it blew over. So, at the time that we made initial contact, we were at 106 mph. But I can say this, I guess in a boat race when you bump, stuff goes crazy.”

Loren Peters (owner/throttleman, LPC Racing): “Billy Allen was coming up on the starboard side.… I scooted over a little and Billy did the same thing. All of a sudden, we’re right up next to each other. We were deck to deck. I see Billy going up, and right after that, I felt lift. My life flashed before my eyes. We went completely over in a split second.”

Scott Porta (owner/throttleman, Porta Performance ) was throttling the catamaran just ahead. He describes the incident: “We were probably running 113 mph. The two boats just behind us were side by side trying to conduct a straightaway pass and positioning for the turn. These two [boats] naturally gathered up next to each other. The compressed tunnel air that normally escapes from under the sides of the boats was stopped when these guys got next to each other. The increased tunnel pressure easily pushed the bows up. Then the wind-drag and momentum took over. Think of it like when you try to slam a refrigerator door as hard as you can and the gasket traps the escaping air and prevents a hard closing of the door. The idea of boats gathering up next to each other and having a blow-over actually isn’t new and is common in single-engine tunnel boat racing. However, this may be a first for an offshore race.”

Porta’s ongoing efforts to refine the running surfaces of these Wright-designed catamarans for competition and recreational use were informed by this dramatic episode as well as by his own accumulated time behind the wheel on that model.

Porta: “Catamarans run on a cushion of air. There are physics issues we felt the need to address. With race and recreational cats running well over 100 mph, our mission has been to improve design: first, to create the largest possible margins for safety in turns and rough water; second, to design for softer landings to reduce driver fatigue and equipment failure; third, to reduce running surface drag for improved performance at lower trim angles. The resulting reduction in frontal area increases speed and stability while creating a larger window of safety. Aerodynamics is the next frontier to explore for the biggest possible untapped gains.”

To simulate the blow-over, we had two options: the conventional wind tunnel and model construction, or computational fluid dynamics (CFD). As in Part 1, CFD was the easy choice for obtaining results quickly and the ability to model subsequent design remedies. Again, we chose TotalSim US (Dublin, Ohio) as our technology partner.

Let’s review the particulars of the case study boat and the theoretical running conditions:

•  Doug Wright 32 ‘ wide-tunnel catamaran
•  5,000 lbs (2,268 kg) fully fueled, ready for passengers
•  Twin Mercury 300XS engines (300 hp, approximately 600 lbs/272 kg each)
•  Flat water
•  Wind speed 0 mph
•  Design speed 100+ mph (161+ kmh)

As speeds approach 100 mph, two primary dynamics contribute to lift and resultant speed on this model:

Engine lift—With a bullet-shaped gearcase and the X-dimension raised to a high level, a hydrodynamic phenomenon occurs. The half-submerged gearcase alone generates enough lift to carry the entire weight of the 600-lb outboard.

Hull lift—The shape of the catamaran tunnel captures and traps air between the sponsons, thus providing lift that supports most of the weight of the boat.

The CFD Assessment and Conclusion

Nathan Eagles, principal at TotalSim, and Scott Porta set out to see how the air currents at 100+ mph influence handling, speed, and efficiency of the catamaran. When Eagles saw the footage and spoke with Porta about the tandem liftoff at Key West, his immediate thought was to apply the tools and experience from other motor­­sports work to help explain why this happened and potentially develop some countermeasures that could reduce the risk of it reoccurring.

At the beginning of the project, Eagles offered a corollary: “Assessing safety and developing countermeasures to reduce the risks posed by aerodynamic forces when vehicles get outside their normal operating envelope is something the motorsports community has worked hard to address for many years. My initial foray was as head of CFD at the Williams F1 Formula One team, where I worked with the F.I.A. [Fédération Internationale de l’Automobile, the sport’s governing body—Ed.] to understand the forces acting on an F1 car as [it] pitched nose up, and at which angle the aero forces overpowered the weight and inertia forces.”

Later, during the development of the aero kits, TotalSim responded to one of the requirements imposed by Indycar. When the nose pitches up, the new bodywork was to be more stable than its predecessor while traveling sideways and/or backward. This meant that as the shape and the form of the car developed for efficient downforce and drag production around the track, TotalSim had to make sure the forces and moments acted to ground the car if it got airborne (its aero kit won the 100th running of the Indy 500 with no serious accidents).

Angles Assessed in Blow-Over Model

The first step in analyzing the Key West event was to understand the typical forces and moments acting on the Doug Wright 32 when running where Porta was out in front and on his own. To do this, Eagles took the same geometry file Dimensional Engineering had created from the FARO scan and built a CFD model that focused only on the surface in contact with the air.

Eagles: “We set the angle of the hull relative to a flat sea state at several positions (Figure 1) and then assessed the forces and moments at each of those positions (Figure 2). The key forces under consideration are the drag (force acting against the forward motion) and lift (vertical force pushing up away from the water). The result of the combination of the lift and drag forces was a pitching moment (nose-up) about the center of gravity created by these forces.”

We can see from Figure 2 that as the angle of the isolated boat increases from 0° to 50°, the drag and lift forces (and resultant) increase as well, as does the pitching moment. We also see that the resultant is nonlinear, meaning that as the angle changes, the curves get steeper, indicating that doubling or tripling the angle more than doubles or triples the forces and moments. This characteristic implies gross instability, because once the aerodynamic forces exceed the weight of the boat and the bow starts to lift, the forces continue to increase at a rate that makes correction exceedingly difficult.

Attack Angle Influence on Lift, Drag, and Pitching Moment of Single Boat

Having established the characteristics of the isolated boat, the next step was to place the boats side by side to see if anything changed. From the footage and the comments from the pilots, Eagles positioned the virtual boats 3 ‘ (0.91m) apart, set the angle of attack (AOA) at 5°, and ran the simulation. Figure 3 shows the same isolated boat forces and moments with the two-boat simulation data super­imposed on top. The results are quite dramatic.

We see both drag and lift increasing compared to the isolated boat, with the drag on each of the side-by-side boats being equivalent to the drag on an isolated boat at around a 7° AOA (suggesting they may be slowing each other down), while the lift of the side-by-side boats is equivalent to an isolated boat at around 16°.The huge changes in lift and associated pitching moment change are greater than the restoring moment of the weight, so the boats are no longer trimmed out, and the bows begin to rise.

Dynamics of a Single Boat vs Boats Running Side by Side

As we saw in Figure 2, as the angle increases, so do the forces; and as the bows come up, the forces go up, the bows rise some more, and this continues until the boat flips over. The CFD force data illustrate a dynamic that would lead to the event we saw in Key West. But why did it happen?

This is where CFD really starts to show its strengths. The forces we have looked at are a result of pressure changes on the surface of the hull. These changes are created by local accelerations and decelerations of the air as it washes over the hull and deck, and CFD can show us how and why these occur. In Figures 4a and 4b the underside of the hull colored by the component of pressure is creating lift for the two different configurations. Yellow depicts low amounts of lift; red is high lift; green is low levels of downforce (the aerodynamic force pulling the boat toward the water); and blue is high downforce.

CFD of Lift and Downward Force on Single Boat

The plots show that the entire tunnel surface is creating lift whether the boat is alone or side by side, and there is not much change between the two scenarios. However, the sponsons tell a different story. The isolated boat is showing strong downforce coming from both sponsons at the section just ahead of where the hull meets the water (blue patch midway down the sponson). This downforce is generated by the air accelerating in the narrowing gap between the hull and the water surface. This is illustrated in Figure 5a as velocity vectors colored by speed, with blue showing low speed and red showing high speed.

Eagles: “As air enters the tunnel, it starts to slow down as it packs up under the boat, and as it progresses it gets squeezed into a tighter volume and starts to push out at the sides, accelerating (red arrows) as it washes outboard over the hull surface. As the air accelerates, its pressure drops, creating suction, and this in turn generates a force pulling the hull towards the water. There are some effects also happening on the deck side, but these are secondary compared to the hull and have not been covered here.”

CFD of Lift and Downward Force on Boats Running Side by Side

Looking at the side-by-side configuration in Figure 4b, we see an effect on the outer sponson similar to what is seen on the isolated boat. However, on the inside sponson we see most of that downforce has been eliminated and replaced by lift across the majority of the surface. This is the source of the liftoff mechanism that caused the blow-over. The velocity vectors of the side-by-side configuration show that air is unable to get out as effectively, as it’s blocked by the sponson of the adjacent boat, as illustrated by the slow-moving blue arrows in Figure 5b. This slow-moving air has higher pressure and therefore does not create the suction we saw in the isolated boat, with the net result that the inside sponsons on both boats now create significantly more lift, disrupting their stable trim and causing the bows of the nearly identical hulls traveling at the same speed to flip quickly and almost simultaneously.

CFD of Air Velocity on Single Boat

“The simplest way to reduce the risk of this happening in the future is to make sure there is sufficient gap between boats that the air can get out,” Eagles said. “However, racing being racing, when you are fighting for the patch of water leading around the buoy, I suspect that this probably will not be what is at the forefront of your thinking.”

He concluded: “A more practical solution would be to adopt something like Indycar or NASCAR and add a device to the boat that when deployed creates a counteracting force that cancels out the lift and stabilizes the pitching moment. This could be a passive device [auto-deploying] or active [driver initiated] and will require discussion with the governing bodies to make sure it does not adversely impact the racing or create issues of its own. I sense there might be a new project on the horizon.”

CFD of Air Velocity on Boats Running Side by Side

Real-World Aerodynamics

Most relevant to designers and builders of recreational powerboats, our case studies show that aero­dynamic design really starts affecting a boat above 60 mph (97 kmh). With multiple higher horsepower outboards being bolted on the transom, almost every boat manufacturer has a model capable of that speed, but aerodynamics are relevant on more sedate vessels as well. Builders use phrases like dry ride, acoustically tuned cockpit, comfortable, and wind free to describe the virtues of even a 20-knot boat. That’s no surprise when social media is full of posts about how “car-like” their recent boating experience had been. The current automotive comfort expectations have raised the bar for everyone. Gone are the days of the passengers in a top-down convertible being exhilarated by the wind in their hair on a gusty open highway. Modern convertibles are acoustically and aerodynamically refined. The open sky is still overhead, but engineering has all but eliminated the noise and wind of the convertible.

Let’s say that a boat owner drives to the marina in a quiet and aerodynamically refined convertible before boarding a newly acquired sport boat, a product that may cost twice or three times as much as the car. Shouldn’t expectations for comfort and noise be the same on the boat as in the car?

Jake Fraleigh, president of Eliminator Boats (Mira Loma, California), on the importance of aerodynamics to his recreational models: “In the past we used a higher deck, and we noticed that people in the back of our cockpits were getting lots of wind buffeting. Our newest models have flattened decks. We pulled the ‘bubble’ out of our top deck, and that allowed our new windshield design to positively affect our aerodynamics for cockpit comfort.”

Because Eliminator is installing more outboards, which means the boats go faster, Fraleigh said, “on both our 31 and 33, we are widening our tunnels now and changing the slope of the deck and tunnel entry, therefore creating more tunnel pressure. We have even added 45° angles to the sponson area upper-deck plane entering the tunnel for better entrapment of air under the boat. We have focused on more lift and therefore a faster, more agile boat.”

Nigel Hook, owner of SilverHook Powerboats (Sanford, Florida), confirmed the importance of CFD modeling during design and model refinement. “The SilverHook was designed as perfectly aerodynamic [with the help of CFD] by Ocke Mannerfeldt of the Swedish firm Mannerfelt Design Team. It has wings, although not movable; it has automatic stabilization. The consumer design has the same CFD advantage. It is fast, efficient, and safe. Only through aerodynamics are we able to manifest the true race-proven features.”

For now, the new minimum expectation for North American powerboat buyers is twin outboards, and the new normal is triples or quads on higher end vessels. More power adds speed, and with speed, airflow becomes very important to boat designers and builders. Boats can and do fly, if only for brief intervals, but managing their seakeeping, safety, handling, and comfort at those speeds requires as much attention to aerodynamic design and analysis as to hydrodynamics. To that end, more manufacturers are using CFD modeling to create and simulate the performance of any given design, especially as they pile on more power to meet market expectations. The results can range from understanding and correcting sources of dangerous instabilities and performance flaws, to quieting the ride in the cockpit and keeping the hair out of your eyes.

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Powerboat Design and Performance: Expert insight into developments past and future Hardcover – October 29, 2019

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The definitive book on powerboat design and performance--a unique wealth of material from the internationally renowned expert in powerboating, featuring contributions from leading designers on everything from hull design to propulsion. Set to become the bible for powerboat owners and operators for years to come, this long overdue analysis and review of modern powerboat design and operation explores how powerboats have developed, why, and how design impacts on control and performance. Every aspect of the powerboat's design is considered individually and as part of the whole. Different hull designs are assessed for their benefits and drawbacks. Engine types (whether petrol, diesel, electric or hybrid) and their influence on performance are explored and the nature and impact of different propulsion systems and driving controls is also examined. All factors that influence operation are featured, from how to optimize performance in varied sea conditions, matching speed to sea state, as well as tackling various common and uncommon scenarios (from running an inlet to coping with tidal races and harbor maneuvering) and issues relating to crew safety. Dag Pike is the world-renowned guru on powerboats. He has attracted contributions from many of the top international powerboat designers, providing a wealth of expert knowledge and specialist insights about modern powerboats. The sum of their know-how makes this book essential for all powerboat owners, operators and designers, whether in the leisure, commercial or military sector, and will help ensure all prospective owners get the right boat for their requirements.

• Print length 224 pages
• Language English
• Publisher Adlard Coles
• Publication date October 29, 2019
• Dimensions 6.92 x 0.79 x 10.15 inches
• ISBN-10 1472965418
• ISBN-13 978-1472965417
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• Publisher ‏ : ‎ Adlard Coles (October 29, 2019)
• Language ‏ : ‎ English
• Hardcover ‏ : ‎ 224 pages
• ISBN-10 ‏ : ‎ 1472965418
• ISBN-13 ‏ : ‎ 978-1472965417
• Item Weight ‏ : ‎ 1.68 pounds
• Dimensions ‏ : ‎ 6.92 x 0.79 x 10.15 inches
• #2,259 in Boating (Books)

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A Guide to Power Catamaran Boats

If you’re into offshore fishing or water sports, the Power Catamaran or “multi-hull powerboat” offers you a great option for your first vessel. These powerboats provide you an excellent combination of performance, stability, and maneuverability.

These boats have a catamaran design, relying on two hulls to float the vessel instead of the typical deep-V hull found on other powerboat models. The multi-hull powerboat is ideal for cruising, and you can set it up for fishing or watersports as well.

With the multi-hull powerboat, you get options for multiple fishing stations over each hull without disrupting the boat’s balance on the water. They are ideal for use in lakes and estuaries, and they excel on the open ocean.

These boats come in lengths ranging from 16 to 30-feet, with plenty of customizable options and accessories. Typically, you get a stern-drive or outboard motor configuration, with center consoles for the driver and loads of storage space onboard.

These boats can carry from six to eight passengers easily, and most models will fit on trailers. This post gives you all the information you need on selecting the right multi-hull powerboat to suit your aquatic needs.

What Is a Multi-Hull Powerboat?

The multi-hull powerboat features a catamaran design, with two hulls running down the boat’s length, featuring a gap between the two. This configuration makes the boat exceptionally stable at higher speeds, allowing fast movement through choppy water inshore or offshore.

The catamaran might seem like a niche boat design. However, it offers you several advantages on the water, such as a smooth ride, stability, and economy. These boats come in a wide range of designs and lengths, with the smallest versions measuring around 12-feet, and the largest extending up to 70-feet or longer.

The longer vessels come with liveaboard facilities and all the amenities you need to spend days out on the water. We like to think of the multi-hull powerboat as the catamaran design of the cabin cruiser or cuddy cabin boat. You get all the same advantages as these models but with an added performance on the water.

You get plenty of options for live wells, rod holders, gear storage, and integrated coolers for drinks and fish. Whether you’re planning a weekend trip or just going out for the day, the multi-hull powerboat is a great choice for your ocean-going excursion.

While the catamaran model is the most popular choice in this category, there are models featuring a tri-hull design. Typically, these vessels cater more towards fishing than performance or watersports, offering slightly less steering maneuverability than the dual hull setup. However, the addition of the third hull brings superior stability to the boat, making them ideal for fishing in choppy water or cruising from island to island on rougher seas.

The ripple hull models typically feature more liveaboard space, with some models having multiple separate living areas beneath the deck.

Benefits of Multi-Hull Powerboats

The Multi-hull powerboat offers you plenty of advantages for fishing, cruising, and watersports. Here are our top reasons for adding this boat to your shortlist of considerations.

Speed and Handling

The multi-hull boat relies on two separate hulls contacting the water. As a result, there is less drag from the hull when cutting through the water. You get faster speeds than you do with a mono-hull design and excellent handling with tight turning circles. These boats do well on open water, allowing for superior stability in rough waters when fishing offshore.

Dynamic Cruising

The multi-hull powerboat features dynamic cruising capability. These boats are most popular with recreational users that want to cruise down the coastline on the weekend or take a few days out on the water for a fishing trip. The built-in accommodations in many designs make it suitable for staying out on the water overnight.

Stability and Performance

Multi-hull powerboats can come with several engine configurations. The motors on these boats offer excellent performance, propelling the watercraft up to speeds of 50 to 80-mph, depending on the model. They also make suitable watersports boats, allowing for skiing and wakeboarding.

Plenty of Storage

The multi-hull boat offers you more storage capability than mono-hull models. You get loads of storage room above and below deck for your dive gear or fishing equipment. There is under-seat storage, and the v-berths in the bow of these models can include plenty of amenities.

Center Console Design

The center console driver configuration is common with the multi-hull performance boat. This driver position gives you more control over the vessel when turning. Some consoles may position closer to the bow or aft of the boat, depending on the length and design features of the boat.

Hardtop Designs

Most multi-hull powerboats come equipped for long ocean-going trips. As a result, they may have a covered driver cockpit leading to below deck accommodations or storage facilities. Some models have wraparound cockpits with doors sealing the cabin, allowing for air conditioning inside the boat on hot days. Other models come with an open plan design and a hard roof.

Trailerable

Most models of multi-hull power bats range from 16 to 24-feet, but there are plenty of longer models. The shorter lengths are easy to trailer, allowing for easy removal for the water and transportation. However, some models may be wider than 10-feet, requiring a special license to operate the loaded trailer. Check with your local authorities for trailer regulations and laws.

Fishing and Watersports Capability

These boats are excellent fishing vessels, offering you plenty of stability for casting on any side of the boat. The center console design means you have walkways on either side of the console, allowing the angler to chase the fish around the boat if it decides to drag the line. Most models also feature setups for watersports like wakeboarding, with T-tower bars or Bimini tops for higher tow points.

Outboard or Stern Motors

The multi-hull powerboat comes with a design for performance out on the water. As a result, these boats usually feature outboard motors with capacities ranging from 150-HP to 450-HP. Some models may use dual-motor setups or stern-mounted motors that hide out of sight.

Multiple Sizing Options

As mentioned, the multi-hull boat comes in a variety of lengths to suit your requirements. Whether you need a large boat for spending days out on the water or a simple day fishing vessel, there’s a multi-hull design to suit your requirements.

Disadvantages of Multi-Hull Powerboats

While the multi-hull powerboat is a flexible design suited for cruising, fishing, or water sports, it does come with a few drawbacks.

Large Engines and More Fuel

These boats feature design and construction for speed, with large outboard motors. As a result, they are somewhat heavy on fuel, especially with a large-capacity dual-motor setup.

Top Multi-Hull Powerboat Models

You have plenty of choices when selecting your multi-hull powerboat. Here are some of our top picks for the best models available.

Calcutta 480

This multi-hull powerboat has a 51-foot length, and it’s ideal for offshore use, providing exceptional stability thanks to the size and the 17-foot beam. It’s one of the largest models available, featuring world-class multi-hull design.

You get a spacious deck with a center console configuration and enough room to walk down either side of the boat when fishing. The dual hull provides exceptional stability combined with the long length, and you get options for diesel-powered or gasoline engines in outboard or in-stern setup to suit your requirements.

The Calcutta brand custom-builds boats for its clients. You get options for fully enclosed bow areas and fishing-style cabins with a roomy helm deck and a sleeping berth included in the bow. You also have an enclosed head for ablutions, but there is no option for a shower.

This model comes with an enclosed cockpit and air conditioning to keep you cool when cruising. The motors on this boat are monsters, featuring a twin setup of 550-HP Cummins diesel inboards available on the sports version for superior power and speed on the water while maintaining the boat’s maneuverability.

There’s a 600-gallon fuel capacity for the thirsty engines, allowing you to spend days out on the water without running out of fuel.

Insetta 35 IFC Hydrofoil

The Insetta 35 IFC hydrofoil offers you the smooth-sailing benefit of hydrofoils, with premium multi-hull designs. The hydrofoil system generates the lift under the hull, allowing for superior, stable sailing in rough water conditions.

The hydrofoil reduces friction and dragging on the hulls, reducing your fuel consumption by as much as 40% compared to other models with a similar dual hull design. The foil fits between the sponsons, featuring design and construction with stainless steel.

Another interesting design feature with this model is the way the inboard motors have positioning towards each other. This configuration allows for maximum thrust for the propellors on the asymmetrical multi-hull.

The foil and motor setup design also allow for much tighter turns than you get with other multi-hull models, giving you similar performance to what you expect in a mono-hull design.

The boat comes with a large coffin box with 156-gallons of space available and an insulated finish. You get eight rod-holders positioned in the bow and aft of the boat. You also get dual 30-gallon transom live wells and an option for a third below the mezzanine seat.

The Insetta 35 IFC hydrofoil comes with a three-pump sea chest, a folding bait station, and plenty of tackle storage. The boat gets its power and performance from dual Mercury 400 Verados, with the vessel topping out at speeds of 58-mph on open, calm waters.

Invincible 46 Cat

This model is the largest in the Invincible range, and it’s a great choice for offshore fishing. This flagship model comes with a 42-foot length and a center console design for easy driver operation. This multi-hull powerboat relies on a hybrid semi-asymmetrical multi-hull giving it great turning capability and maneuverability out on the open water.

The Invincible 46 Cat features a stepped hull with fast acceleration and plenty of lift. You get a quad engine setup with Mercury 450 Racing outboard motors, and the craft can reach a top-end speed of 78-mph. Other notable features of this boat include a vacuum-infused hull and grid-stringer system for an “invincible” boat that’s virtually unsinkable.

Bali Catspace

If you’re looking for a luxury powercat model, the Bali Catspace Motoryacht is a fantastic – but expensive choice. This model features a design from legendary boat maker Olivier Poncin. This model is a natural cruiser and ideal for the longest ocean-going trips.

The dual hull and high ride height from the water provide exceptional stability for the boat, even in the roughest offshore and coastal waters. The boat comes with a lounge on the deck, and there’s plenty of room around the center console cabin to walk the length of the boat on either side of the vessel. The top level of the boat features the captain’s station and wheelhouse, with luxury living quarters underneath.

You get a huge lounge and a v-berth with sleeping quarters for spending the night out on the water. The cockpit presents the captain with a 360-degree view of the water, and the high riding position gives you a view of the ocean that extends for miles.

The boat comes with all the amenities you need, including tables, a full kitchenette, and luxury sleeping accommodations. There are plenty of entertainment options for TVs and stereo systems down below, with an optional hardtop Bimini.

The Bali Catspace Motoryacht receives its power from a single or dual engine setup featuring 150-HP or 250-HP Yamaha motors.

Wrapping Up

With so much variety available in multi-hull powerboats, you have options for any activity out on the water. These boats are more common in coastal waters, and they make excellent fishing vessels.

Decide on the model that suits your activity, as most have a purpose-built design for fishing, watersports, or cruising. There are plenty of customization options, so make sure you keep a budget in mind as the additions can cost more than 20% of the boat’s initial sticker price, increasing your costs.

John is an experienced journalist and veteran boater. He heads up the content team at BoatingBeast and aims to share his many years experience of the marine world with our readers.

NVIDIA GB200 NVL72

Powering the new era of computing.

• Introduction

Get Started

Unlocking Real-Time Trillion-Parameter Models

GB200 NVL72 connects 36 Grace CPUs and 72 Blackwell GPUs in a rack-scale design. The GB200 NVL72 is a liquid-cooled, rack-scale solution that boasts a 72-GPU NVLink domain that acts as a single massive GPU and delivers 30X faster real-time for trillion-parameter LLM inference.

The GB200 Grace Blackwell Superchip is a key component of the NVIDIA GB200 NVL72 , connecting two high-performance NVIDIA Blackwell Tensor Core GPUs and an NVIDIA Grace CPU using the NVIDIA® NVLink®-C2C interconnect to the two Blackwell GPUs.

The Blackwell Rack-Scale Architecture for Real-TIme Trillion-Parameter Inference and Training

The NVIDIA GB200 NVL72 is an exascale computer in a single rack. With 36 GB200s interconnected by the largest NVIDIA® NVLink® domain ever offered, NVLink Switch System provides 130 terabytes per second (TB/s) of low-latency GPU communications for AI and high-performance computing (HPC) workloads.

Supercharging Next-Generation AI and Accelerated Computing

Llm inference.

30X vs. NVIDIA H100 Tensor Core GPU

LLM Training

4X vs. H100

Energy Efficiency

25X vs. H100

Data Processing

18X vs. CPU

LLM inference and energy efficiency: TTL = 50 milliseconds (ms) real time, FTL = 5s, 32,768 input/1,024 output, NVIDIA HGX™ H100 scaled over InfiniBand (IB) vs. GB200 NVL72, training 1.8T MOE 4096x HGX H100 scaled over IB vs. 456x GB200 NVL72 scaled over IB. Cluster size: 32,768 A database join and aggregation workload with Snappy / Deflate compression derived from TPC-H Q4 query. Custom query implementations for x86, H100 single GPU and single GPU from GB200 NLV72 vs. Intel Xeon 8480+ Projected performance subject to change.

Real-Time LLM Inference

GB200 NVL72 introduces cutting-edge capabilities and a second-generation Transformer Engine which enables FP4 AI and  when coupled with fifth-generation NVIDIA NVLink, delivers 30X faster real-time LLM inference performance for trillion-parameter language models. This advancement is made possible with a new generation of Tensor Cores, which introduce new microscaling formats, giving high accuracy and greater throughput. Additionally, the GB200 NVL72 uses NVLink and liquid cooling to create a single massive 72-GPU rack that can overcome communication bottlenecks.

Massive-Scale Training

GB200 NVL72 includes a faster second-generation Transformer Engine featuring FP8 precision, enabling a remarkable 4X faster training for large language models at scale. This breakthrough is complemented by the fifth-generation NVLink, which provides 1.8 terabytes per second (TB/s) of GPU-to-GPU interconnect, InfiniBand networking, and NVIDIA Magnum IO™ software.

Energy-Efficient Infrastructure

Liquid-cooled GB200 NVL72 racks reduce a data center’s carbon footprint and energy consumption. Liquid cooling increases compute density, reduces the amount of floor space used, and facilitates high-bandwidth, low-latency GPU communication with large NVLink domain architectures . Compared to NVIDIA H100 air-cooled infrastructure, GB200 delivers 25X more performance at the same power while reducing water consumption.

Databases play critical roles in handling, processing, and analyzing large volumes of data for enterprises. GB200 takes advantage of the high-bandwidth memory performance, NVLink-C2C , and dedicated decompression engines in the NVIDIA Blackwell architecture to speed up key database queries by 18X compared to CPU and deliver a 5X better TCO.

Technological Breakthroughs

Blackwell architecture.

The NVIDIA Blackwell architecture delivers groundbreaking advancements in accelerated computing, powering a new era of computing with unparalleled performance, efficiency, and scale.

NVIDIA Grace CPU

The NVIDIA Grace CPU is a breakthrough processor designed for modern data centers running AI, cloud, and HPC applications. It provides outstanding performance and memory bandwidth with 2X the energy efficiency of today’s leading server processors.

Fifth-Generation NVIDIA NVLink

Unlocking the full potential of exascale computing and trillion-parameter AI models requires swift, seamless communication between every GPU in a server cluster. The fifth-generation of NVLink is a scale–up interconnect that unleashes accelerated performance for trillion- and multi-trillion-parameter AI models.

NVIDIA Networking

The data center’s network plays a crucial role in driving AI advancements and performance, serving as the backbone for distributed AI model training and generative AI performance. NVIDIA Quantum-X800 InfiniBand , NVIDIA Spectrum™-X800 Ethernet , and NVIDIA BlueField®-3 DPUs enable efficient scalability across hundreds and thousands of Blackwell GPUs for optimal application performance.

Specifications

GB200 NVL72 1 Specs

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Nvidia unveils blackwell b200, the “world’s most powerful chip” designed for ai, 208b transistor chip reportedly reduces ai cost and energy consumption over h100 predecessor..

Benj Edwards - Mar 19, 2024 3:27 pm UTC

On Monday, Nvidia unveiled the Blackwell B200 tensor core chip—the company's most powerful single-chip GPU, with 208 billion transistors—which Nvidia claims can reduce AI inference operating costs (such as running ChatGPT ) and energy consumption by up to 25 times compared to the H100 . The company also unveiled the GB200, a "superchip" that combines two B200 chips and a Grace CPU for even more performance.

Further Reading

The news came as part of Nvidia's annual GTC conference, which is taking place this week at the San Jose Convention Center. Nvidia CEO Jensen Huang delivered the keynote Monday afternoon. "We need bigger GPUs," Huang said during his keynote. The Blackwell platform will allow the training of trillion-parameter AI models that will make today's generative AI models look rudimentary in comparison, he said. For reference, OpenAI's GPT-3, launched in 2020, included 175 billion parameters. Parameter count is a rough indicator of AI model complexity.

Nvidia named the Blackwell architecture after David Harold Blackwell , a mathematician who specialized in game theory and statistics and was the first Black scholar inducted into the National Academy of Sciences. The platform introduces six technologies for accelerated computing, including a second-generation Transformer Engine, fifth-generation NVLink, RAS Engine, secure AI capabilities, and a decompression engine for accelerated database queries.

Several major organizations, such as Amazon Web Services, Dell Technologies, Google, Meta, Microsoft, OpenAI, Oracle, Tesla, and xAI, are expected to adopt the Blackwell platform, and Nvidia's press release is replete with canned quotes from tech CEOs (key Nvidia customers) like Mark Zuckerberg and Sam Altman praising the platform.

GPUs, once only designed for gaming acceleration, are especially well suited for AI tasks because their massively parallel architecture accelerates the immense number of matrix multiplication tasks necessary to run today's neural networks. With the dawn of new deep learning architectures in the 2010s, Nvidia found itself in an ideal position to capitalize on the AI revolution and began designing specialized GPUs just for the task of accelerating AI models.

Nvidia's data center focus has made the company wildly rich and valuable , and these new chips continue the trend. Nvidia's gaming GPU revenue ($2.9 billion in the last quarter) is dwarfed in comparison to data center revenue (at $18.4 billion), and that shows no signs of stopping.

A beast within a beast

The aforementioned Grace Blackwell GB200 chip arrives as a key part of the new NVIDIA GB200 NVL72, a multi-node, liquid-cooled data center computer system designed specifically for AI training and inference tasks. It combines 36 GB200s (that's 72 B200 GPUs and 36 Grace CPUs total), interconnected by fifth-generation NVLink, which links chips together to increase performance.

"The GB200 NVL72 provides up to a 30x performance increase compared to the same number of NVIDIA H100 Tensor Core GPUs for LLM inference workloads and reduces cost and energy consumption by up to 25x," Nvidia said.

That kind of speed-up could potentially save money and time while running today's AI models, but it will also allow for more complex AI models to be built. Generative AI models—like the kind that power Google Gemini and AI image generators —are famously computationally hungry. Shortages of compute power have widely been cited as holding back progress and research in the AI field, and the search for more compute has led to figures like OpenAI CEO Sam Altman trying to broker deals to create new chip foundries.

While Nvidia's claims about the Blackwell platform's capabilities are significant, it's worth noting that its real-world performance and adoption of the technology remain to be seen as organizations begin to implement and utilize the platform themselves. Competitors like Intel and AMD are also looking to grab a piece of Nvidia's AI pie.

Nvidia says that Blackwell-based products will be available from various partners starting later this year.

reader comments

Promoted comments.

I would be genuinely interested in a deeper dive on how these types of specialty cards are setup and used by the likes of OpenAI or AWS. I know you don't just toss them on an x64 motherboard in a server chassis, but what sort of back-plane do they use in the cabinet, how are they interfaced with to program and run jobs on them, and what sort of supporting hardware is needed to setup a cabinet full of specialty AI tensor cards? I assume its similar to how a supercomputer is typically setup with a ton of compute nodes connected to a fabric, and then supervisor nodes that feed jobs to the compute nodes and then feed the results back out to a coordination node where the job is setup and results are read from.

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