Multihull Structure Thoughts

It would probably have achieved the very exact opposite.

 

There are designers that create innovative solutions for those who can afford it. The wealthy love rarity, uniqueness and will pay for it. Lazzarini Design Studio caters for this market. Pagurus is a power catamaran that is designed to travel through water driven by outdrives or travel over sand and mud via screw drives in the bottom of hulls (see first jpegs). Th remainder of the cat has many innovative ideas such as storing a Tesla Cybertruck on its main deck which can be lowered onto the sand when the cat is driven onto the shoreline.

This is just one of Lazzarini Design Studio vessels which can be viewed at: MARINE https://www.lazzarinidesignstudio.com/marine

The Pagurus is 82 x 30 foot with a displacement of 142,000 lbs. The hulls length to beam is12.75 to 1. The draft is 16 ft. The 2 main water power engines are1780 HP Caterpillars. The speed in water is 18 knots cruise and 25 knots peak speed. The 4 engines for the land screw drives are 440 hp Yanmars for beaching. The maximum speed on sand is 20 KMH. The fuel is 8000 ltr. There is a vast solar array and battery power to allow some electric motive power.

The accommodation is hull based with 5 guests and 12 crew. The main bridge deck is an open space that can store either EG a Cybertruck or full seating table etc. The floor of the main saloon can be lowered to water or sand level to give you a different view of the world or allow you to drive your vehicle on or off the cat. I suspect there will be a luxury finish, and the guests will be very happy.

The build is listed as “69% steel and 31% carbon fibre with a 24 months construction time”. Not mentioned is how many million is required to build and launch this cat.

The jpegs will give the idea of a very innovative cat. PS the last jpeg is the "military version of this cat".

 

Paw Patrol will definitely order one of these .

 

The Vapor Cat has been around for a decade in various sizes, the size we will look at is the 5 meter (16.4 foot). The cat has an “original” hull shape that evolved from the 1970’s when a boat manufacture cut a 30 foot deep V hull in half and inserted a wing deck between the 2 halves. Vapor Cat developed this approach and refined it to work in smaller cats.

Vapor Cats feature a unique bow shape that produces an extended waterline length and facilitates a finer entry angle thus giving the vessel handling characteristics typical of much larger vessels. The asymmetric tunnel geometry generates spray at specific points inside the tunnel creating a high-density air/water vapor cushion that the hull then rides on. Full-length longitudinal steps give the hull lift and dynamic stability.

The Vapor Cat 5 is 16.4 x 8.2 foot with a weight of 1,344 lbs and a displacement of 3,020 lbs fully fueled. The engine can be a 70 HP outboard to a 140 HP outboard with a 2.1 foot leg length. 130 litres of fuel can be carried. The hull has a 20 degree deep V.

The cat can carry 5 people in the open cockpit. There is an inbuilt ice chest (esky) forward.

The construction is Vacuum infused advanced composite construction hull and deck. The hull construction features vinylester resin solid running surfaces with foam-cored topsides. Multi-axial fabrics are used throughout. All Vapor Cats are designed and built to Australian commercial craft standards (NSCV).

The jpegs give the idea.

 

Seems to be a proven -if not exactly efficient- concept )

 

I know them . My biggest concern of this Lazzarini design is ground pressure . Another is lack of suspension , another is highly loaded by water pressure screw covers.
They are not present at pictures but I hope they exist . Add salt water and this is really challenging project . I spended some time thinking about similar designs.

 

Another Lazzarini Design Studio vessel with Italian flair. Sea Flower is best described as a mini cruise ship for 100 guests. The 105 crew should keep the guests very happy and hopefully will receive significant tips at the end of the cruise. This design is intended to allow guests to have their own grass covered balcony overlooking the 15 meter (49 foot) onboard swimming pool. This will be high class hotel accommodation on a travelling platform around eg Greek Islands. This will not be 4000 people squeezed into a cruise ship.

The Sea Flower is 319 x 105 foot with a “displacement of about 3000 tons (guesstimate)”. The draught is 28 foot. The hull type is a catamaran swath. The length to beam at waterline is 27 to 1 but the underwater tubular hull has a length to beam of 12.3 to 1. The underwing clearance is 15 foot. A Swath hull is aimed at being more sea kindly by having less water surface area to react to waves. The concept works but it does not remove all sea motion. Engine power is unknown but there is a lot of solar arrays for additional electrical support for things like lifts etc that are likely to be aboard.

The individual cabin accommodation should be luxurious, but the toys will be vast. The bridge deck being 5 stories high, I would suggest lifts will be installed and all the swimming pools will allow you to soak in comfort in the sunnier climates. The helicopter landing pad on top of the accommodation will allow those to transfer to and from the vessel when the harbors are too shallow. They can also use the support boats stored in the underwing of the cat.

Performance is unknown but I have one certainty, the cat will travel at a speed that will not upset its high paying guests. The jpegs will give an idea of this conceptual design.

 

A Polish company Almare SP (Ltd) has some interesting power catamarans that are designed for commercial use but also produce some good cruiser too. The cat I will initially focus on is an example of what a heavy displacement cat is capable of. The build is for a Norwegian operator of fishing farms.

The power cat is 59 x 39.3 foot with a weight of 112,000 lbs (50 tons) prior to engines etc installed and a load capacity of 180,000 lbs (80 tons) for an all up displacement of 292,000 lbs (130 tons). The length to beam on the hulls is 4.5 to 1. It draws 6.4 foot over the hull and 7.4 foot over the propeller skeg. This is a heavy displacement cat and I would not expect more than about 10 to 12 knots of speed when driven by some powerful diesels.

As this cat has 13 foot wide hulls there is enough room for crew cabins along with a roomy forward pilot house, but the main function is carrying heavy loads and the catamaran has 2 cranes on the aft deck of 85 and 32 tones of lifting capacity. There is also a 30 ton net winch and capstans located on the aft deck.

The build is mainly NS6038 aluminum with a combined frame system consisting of transverse web frames and longitudinal stringers, and three watertight bulkheads.

This is very much the form follows the customers’ requirements which results in a functional design. The jpegs give the idea.

 

The second catamaran by Polish company Almare SP (Ltd) . The cat again is an example of a heavy displacement cat. The build is for a Norwegian operator of fishing farms but could be used as fishing cruises for anglers or any jobs, by port authorities, institutions. Built 4 pieces for Norwegian client.

The catamaran is 26 x 18.7 foot with a weight of 11,650 lbs. The hull length to beam is about 4.2 to 1. Draft over the hull is 2.5 foot. The hulls have a tunnel for the propeller to allow a shallower draft. Again, this is a heavy displacement cat that will probably be able to carry 11,200 lbs (5 ton) plus loads on its decks.

The build is aluminum with a combined frame system consisting of transverse web frames and longitudinal stringers, and watertight bulkheads. The finish is for commercial use. Aluminum does not require painting unless you want it “pretty”. Each of the “lines” on the plating will reflect a frame or a stringer line.

The hull shape would indicate a sort of 8 to 9 knot cat driven by a couple of inboard diesels. The bow thruster on one hull is interesting for maneuverability.

A very practical work boat that could be turned into a small, long distance cruiser Capable of having large fuel tanks) with good accommodation (large deck space and wide hulls). The jpegs give the idea.

 

Boatstogo from Miami Florida have a range of inflatable boats from kayaks to power boats. They also have a range of inflatable catamarans. About 6 years ago they had a sailing catamaran which now appears not to be available but was interesting as a machine for those who want a bit of transportable fun.

The Saturn sailing cat option was 13 x 6 foot with a weight 73 lbs and a load capacity of 1200 lbs. The supporting cylinders are 1.5 foot in diameter with 3 foot between the tubes. Each tube has 3 air chambers in them. The rig is a lanteen of about 40 square foot with 9.5 foot long boom and gaff. The rudder is a steering oar. The bottom half of an oar is used as a lee board to provide lateral resistance. A 10 hp outboard could be installed.

This cat can sail with 1 or 2 people and is capable of being rowed or powered if required.

Bottom made of extra heavy-duty 1.5 mm PVC. More holes can be cut in bottom if needed. CR385 cataraft can be used with or without drop stitch floor. Rafts tubes are made of heavy-duty 1,100 Dtex High Strength PVC fabric coated on both side with 1100 g/m2, 0.9 mm. PVC fabric is thick, puncture proof and abrasion resistant. Industry standard Halkey-Roberts flat valves design with pushpins. The sailing version has an integrated mast step and steering oar attachment on the inflatable “cross beams”.

The jpegs give an idea of the cat which can be packed into a 3 x 2 x 1.3 foot size package. A bit of fun.

 

This 11.4-meter High Performance Catamaran from the designer and builder High Performance Marine from Busselton WA (Australia). Its wide beam and high tunnel clearance deliver offshore performance with good deck space for fishing, diving and cruising.

The 37.5 x 14.4 foot planning catamaran with a displacement of 15,700 lbs has deep V hulls. The draft is 2 foot. The engine power is 2 x Mercury Outboard 400hp V10 Mercury Outboard XXXL with a peak speed of 40 knots and a cruise speed of 30 knots. It carries 2200 litres of fuel which can provides some range but 800 HP uses a lot of fuel when pushed at peak speed.

There is a forward cabin that has a 2 berth cabin forward on one side with a toilet shower available. The bridge deck includes a 2-person helm with navigation equipment and joystick control. There is also raised U-shaped dinette with multiple seating configurations for entertaining or relaxing. There can be an galley and entrainment area depending on the function of the cat.

The build is aluminum throughout with frames, bulkheads and stringers support. The builder can tailor a vessel with bespoke options to match your unique needs. The first 2 builds will be completed in 2025.

An interesting aluminum build. The jpegs will give the idea.

 

Long-term energy independence and a minimal carbon footprint were high on the brief given to French designers Martin Defline and Joubert/Nivelt for this 48ft cruising cat. The AERO-48 is an offshore catamaran was developed as a concept in about 2015. The cat was built and launched with many features which resulted in the claim of running “100% electric and totally autonomous”.

The cat is 48 x 25.4 foot with a weight of 18,000 lbs. The 65 foot mast carries a headsail only rig with a big overlapping genoa to provide the sail power. Length to beam is about 9 to 1. The draft is 2.3 foot over the hull and about 4.25 foot over the tandem keels. The motive power pair of electric saildrives that also generate power when the boat is sailing. The large solar panel array and hydrogenators (the electric motors acting as a generators) with batteries that can be recharged in 15 hours by the solar panels. The yacht can cruise at 4 knots on a limited range under battery power alone but can cruise at 4 knots all day whilst the sun is shining.

The build is foam glass in epoxy with carbon fiber reinforcement.

The cat has 6 berths in the hull with a head and shower. There is a galley in 1 hull. The bridge deck has seating for the crew and can act as an open air saloon under the large bimini roof carrying the solar panels.

No performance data is available but I would suggest a cat capable of 10 knot averages and peaks near 20 knots due to its relatively light weight and available sail area. A good fast cruiser with limited cabin accommodation. The jpegs give the idea.

 

The angled forward triangular supports for the bimini that maximize forward view is a nice detail.

 

This is about a specific Gunboat 60 called Moonwave. The Nigel Irens design was manufactured in China then shipped to France for fitouts and upgrades in 2012. The cat was initially set up for charter work then did an around the world cruise. The owner spared little expense in the original build with a large rig and hybrid power system using solar panels, wind turbines and regenerative propeller drives to top up the batteries.

The Gunboat 60 is 68 foot including the bow sprit, 60 x 28.2 over the hulls with a weight of 35,700 lbs and a displacement of 42,000 lbs. The87 foot all-carbon rotating carbon fiber wing section mast from Marstrom and carbon Lorima Boom has unidirectional Aramid fiber shrouds with integral carbon chain plates, Aramid forestays (x 2) with custom Facnor furlers. The sail area upwind is 2,239 sq ft and downwind 4,305 sq ft. The length to beam is about 13 to 1. The draft is 3.5 with rudders and boards up, 5 foot over the rudders when down and 11.5 foot with the centreboards down. The underwing is 3.3 foot of the water. There are 2 x 25 KW electric engines supported by batteries and associated generation equipment.

The accommodation is for 8 guests and 2 crew. The master stateroom has a Queen-size berth, master head and shower. The guest cabins have queen size berths, two with toilets and showers and one with a toilet. The separate crew quarters have 2 single berths, shower and toilet. The salon has a galley, lounge, and dining table, comfortable weather proof Italian style sofas finished in Ultra-Leather and an internal helming position. There is a separate sailing cockpit with outside steering station forward of the main salon. Aft there is a spacious cockpit for lounging and entertaining.

The boat was built in composite construction in 2012 at the Gunboat facility in Xiamen, China. Composite construction of vacuum-bagged, infused post-cured SP epoxies, Core-Cell foam sandwich core construction with carbon fiber skins & woven carbon outer skins for impact resistance. The hull laminate is carbon fiber set in epoxy resin, fully infused and post-cured over a CoreCell foam core. All interior furniture and components are likewise foam-cored and are skinned with fine wood veneers. The underwater foils are centerboards instead of daggerboards, to improve crash-worthiness, are also carbon, as are the rudders, which are retractable. The centerboards are controlled by hydraulic rams, with shear pins that let the boards kick up on impact.

Performance, remember this is a global cruiser, as fast as wind speed to about 15 knots, Moonwave did 21 knots on her initial test sail and has done 300 mile days. Her top has been a near 400 mile day. It helps that the owners had 2 permanent crew for 10 years that learnt how to sail the boat well.

Now we get to an interesting part of the story. Moonwave has had a few upgrades such as: the hybrid drive system, parts of the rig, upgraded internal layout, several parts of the electrics and plumbing systems etc. The basic structure is sound but the ongoing maintenance was interesting. The person who said it takes 10% of the cost of the boat to maintain and run it every year could be accurate in this case.

One very good very fast cruising cat that many should have but few can afford. The jpegs give the idea.

 

Funny, I was actually thinking the opposite -like what the heck happened between rendering and execution?

While I understand and can appreciate the effort to not obstruct the view, to me it looks like they gave up on trying to make a streamlined top that complimented the hulls like the one shown in the renderings, with those supports looking quite fugly from different angles to my eyes.

I do like the concept and minimalist design.

There are some similarities to what I have planned for my big solar cat build.

Unfortunately I won’t be able to incorporate transom steps to the water, so instead I’m thinking of installing an elevator between the two hulls at the stern.