Multihull Structure Thoughts

Candela is a very serious electric power boat company that has produced many higher speed (up to about 30 knots) power boats. The Swedish company wants to get near zero emissions for boating and saw an opportunity to create a ferry for some public transport runs around Stockholm. The vessel created is an electric hydrofoil ferry capable of carrying 30 passengers.

The Candela P-12 is 39.6 x 14.76 foot with a weight of 21,280 lbs and a carrying capacity of 30 passengers and 2 crew. The draft varies between 9.3 foot at rest and 3 foot in foiling mode. The engine power is 44 KW total of which only5 kw/nautical mile is used at service speed. The batteries have 252 KW capacity with a recharge capacity of 175 KW/hour in DC mode. The top speed is 30 knots. The service speed is 25-27 knots with a range a range of 40-50 nautical miles at 25 knots service speed.

This allows the passengers from the suburb of Ekero to Stockholm’s city center on the P-12 to make the trip in 25 minutes compared to 55 minutes on the old ferry. If the trial is successful in 2024 it is estimated the reduced energy consumption, low maintenance needs and possibility to increase passenger volumes, its estimated that operational costs will be reduced by at least 40% compared to the old ferries on the trip.

An interesting side light is old style ferries are restricted to 12 knot speeds around Stockholm. If they move any faster, they make wake waves that disrupt water traffic. But that limit doesn’t apply to the P-12. Its hydrofoils cut through the water with barely a ripple. The safety aspect of the foiling ferry has also been taken seriously. The foils are design to break at specific points if the ferry hits something at speed so there will be no damage to the hulls and the ferry can continue in displacement mode or be towed to land without threat to the passengers.

Candela has several options of the base boat to suit various commercial runs but an interesting option is the private yacht market for those who just want to travel around a local area for a day in what could be a very effective cruiser.

The electric Ferry market place is expanding rapidly globally but there is only one thing limiting it. The provision of high powered charging facilities at wharfs etc. Electric ferries need to be partially recharged between each run and high speed charges can download a half charge during a 20 minute turn around but not all locations have the power supply or facilities to recharge.

A very interesting development which needs to be followed. The jpegs give the idea.

 

That and it’s about as aerodynamic as a brick, built with a chopper gun etc etc etc.

 

I repaired one back in the day, broken from the slamming, chopper gun lay up, scary.

 

On page 227 we had an item about the Cure 55 fast cruising catamaran. This is an update. The Cure 55 catamaran production project from Cure Marine was designed by Paul Bury Principal Naval Architect. The Cure 55 project was conceived to be a true sailors cruising catamaran able to be handled shorthanded. The Cure 55 is 58.3 foot length over hull and prodder with 54.5 x 28.5 foot hull shell. The light displacement is 20,095 lbs with a maximum displacement of 27,370 lbs. The 76 foot Hall carbon spar has a mainsail of 1,173 square foot, a self-tacking jib of 592 square foot and a gennaker of 2,110 square foot. There are Profurl furlers for the staysail, jib, and Code Zero. Dyform rigging is standard, and the running rigging is Dyneema core with Technora cases for heat and wear. The hull length to beam is 12.2 to 1. The draft ranges from 4.3 foot to 7.9 foot when the daggerboards are down. The underwing clearance is 3.3 foot. There are twin 57hp Yanmar saildrives with Gory three-bladed folding screws.

Next designer Angelo Finocchiaro came on board since we last looked at the Cure 55. He's suited to this company as Angelo lives in a digital world, but has a complete understanding that the products he helps to create, operate exclusively in an analogue environment. There is just one door separating his working environment of laptop and screens from the floor where they making the Cure 55. Result, all the panels for construction are sorted out digitally first, prior to any construction.

Paul Bury said "We're also pushing the boundaries with every technology available. So, we're obviously using 3D modelling and 3D printing, but we're then integrating it all with 3D scanning to be totally precise about our measurements. In every single area where we have some concern, or we're not a hundred percent sure, we go for a full-scale, one-to-one mock-up. This is especially important from an ergonomic point of view, as everything needs to work and flow nicely for a good living experience whilst on board."

The construction is mainly epoxy resin infused carbon fibre throughout. The design from the very start was aimed at performance and ease of production build. To quote Cure Marine “Production of the Cure 55 catamaran has its foundations in the Designed For Manufacture principal and is underpinned and supported by some of the latest technology currently in use in global boatbuilding.” Cure Marine is at the forefront of composites design and manufacturing. They utilise an array of in house, state of the art automated machinery. Including robotic equipment, CNC Machines, laminate cutters and one of the largest 3D Printers in the southern hemisphere. To quote the builders “Did we mention displacement? Unfortunately, I just can't accept, or it probably would've bugged me fairly heavily, if I had ended up with a 50 odd foot cat that was in 13, 14, 15 metric tonne lightship range. I know that that is not a high-performance boat. I've built 52-foot high performance sailing cats that have come in at six and a half tons, and 60-footers at 10 and 11 tons. That's the standard that I was going to stick to."

In terms of the interior, the work was put into setting the parameters precisely, so that the panels work together harmoniously. Bury supplied the panel and laminate information, and the Cure's Director, Ian McMahon overlaid that real-world experience he is so renowned for. "I would say that they run at the same time. Every decision you take has to be taken in consideration of everything else. So, the texture of the material will be dependent on what's available in the market, and also what's best with the purpose of building the boats. Everything is connected and there is not one single choice that doesn't affect anything else in the boat," stated Finocchiaro.

As the jpegs show the Cure 55 is near launching and has already 4 additional orders on the books. Core Marine has just launched the custom one off Cure 70 designed by Stuart Bloomfield in the last set of jpegs, all carbon and don’t ask the price.

 

The Euro 1480 Bi-Plane charter catamaran designed by Jeff Schionning is now being built. The client wanted a charter cat that was going to attract attention and be relatively simple to handle. Also the masts being placed near the outer edges of the vessel allowed the interior bridgedeck space to be utilised more effectively.

The Euro 1480 is 48.5 x 26.3 foot with a weight of 23,000 lbs. The mast heights are unknown but they will carry 2 x 597 square foot mainsails and 2 x 231 square foot jibs. The keels are daggerboards. The underwing clearance is 2.7 foot. The engine power will be 2 x 20 to 40 HP inboard diesels or an electric motor setup.

The build, named Ad Astra, is being built at Whitsundays-based Liquid Force Marine for Mackay-based Kevin Berry, who plans to charter the boat during peak season. It will also feature electric as well as wind propulsion, using a pair of lithium-ion batteries energised via 6kW solar panels mounted on the roof to power electric motors on each hull.

The interior layout of the Euro 1480 Bi-Plane features a large main cabin with ensuite situated forward on the bridgedeck, with a walk-around galley behind leading out to a large cockpit with plenty of seating for guests. Two queen cabins are located down in each hull, with their own toilet and shower and a smaller berth forward. This layout would suit skippered chartering with crew occupying one cabin and guests in the main cabin, or any desired combination. The bi-plane rig means easy sailing and sail handling with minimal sail controls cluttering the deck space.

Whitsundays-based Liquid Force Marine director David Morris said building a vessel to survey and ASMA compliance added more layers and complexities to the process and the build will take 2 years with 4 staff and at times an additional 4 staff. Yes, that adds up to 20,000 plus person hours to build a 48 foot cat to a high standard.

The Euro 1480 is mainly built from DuFLEX/foam panels. Depending on the part, various thicknesses of Divinycell H80 and H130 foam cores and a combination of high strength E-fibreglass in various configurations. Combined in the DuFLEX format, with high performance epoxy and fibreglass or carbon reinforcements weight targets, stress and impact loads and other engineering criteria can be achieved without compromising the performance or comfort. To streamline the composite panel joining process, ATL Composites has developed the proprietary Z-Press. The press applies heat and pressure to cure the epoxy adhesive on the Z-Joints. Additional reinforcing is being supplied by ATL Composites including E-Fibreglass taping and carbon reinforcements, and the Euro 1480 will be laminated with KINETIX R246TX with a combination of hardeners to offer options for cure and working times, and of course WEST SYSTEM epoxy and powder modifiers for all bonding, coving, filleting and fairing for the project.

The cat should be nearing completion now but I do not have actual launch jpegs only the initial concept jpegs and some build jpegs of the ATL Duflex components but an interesting build and concept.

 

H-2, short for Hippocampus 2, a 110-footer (33.5m) cruising power catamaran designed by John Marples for Brian Schmitt, 67, a real estate executive in the Florida Keys. Brian owned a Marples 57 foot power cruising cat built in Constant Camber wood that he was very happy with and wanted something larger. Marples drew an 80 footer for Brian but Brian wanted more space and range which resulted in an agreed 110 foot design. Brian and Marples made sure the design would meet all regulatory requirements (ABS 2016 design guidelines for pleasure motor yachts) and brought in various sub contractors like Geoff Van Gorkom who did the structural engineering, HydroComp to do the drive train and 5 blade propellers, Lithionics for the lithium iron batteries, Smart Solar for the electronics and solar panels etc. Page 143 gives some further build shots of H-2 but the details below are a structural build update.

H-2 is 110 x 35 foot with a weight of 230,000 lbs with a displacement 330,000 lbs fully loaded, carrying 12,000 gallons fuel. The draft fully loaded is 5 foot. The chosen propulsion system comprises two MTU 10V 2000 M96, 1505-mhp diesels with ZF 3000 flange-mounted marine gears driving through shaft drives to 3 foot wide 5 blade propellers, providing an estimated top-speed range of 20–22 knots, cruising speeds of 12–15 knots, and 10–13 knots for long-range voyaging. The range is estimated to be 5000 miles at long range cruise speed or 10.5 litres per nautical mile, not to bad for a 110 footer.

John Marples said, the simple chine hull shape was due to the speed length of the hull and relatively “slow” speed, and the chine hull shape will have little effect on the overall efficiency. Also, the trade-off for overall beam width involves room versus roll motion. A wider catamaran responds more quickly to roll in seaways but with less amplitude, whereas a narrower beam rolls more slowly with slightly more amplitude. The slower roll is preferable as long as overall roll stability is maintained. The vessel is supported by two buoyancy chambers (hulls) with distance between them, motion has little to do with roll inertia, but rather with response of the hulls to the seaway. Each hull responds to a passing wave independently by heaving (up/down) and rolling, which is a circular motion around the center of gravity (CG) that translates to lateral motion when standing above the CG, especially high up on the bridge. Power catamarans, unlike sailing catamarans, do not require wide hull spacing to generate righting moment (to support a sail plan), so they can have closer hull spacing, which still preserves sufficient stability, slows wave-response roll characteristics, and takes up less space in port.

The accommodation has a giant salon and galley, four en suite staterooms, including a full-beam master, and an office that converts to offer more sleeping quarters. There’s also crew’s quarters and a second galley. The 600-square-foot aft deck offers an outdoor galley and entertainment space which is covered by a helipad. There are cranes and dive lockers and a level of redundancy you don’t often see on a recreational vessel. It’s being built to cruise to the poles and anchor out in the Galapagos—it’s totally self-sufficient.

To give you an idea about the level of professionalism involved in this project the build shed is the ex Gunboat factory (300 x 80 foot) in South Carolina, Brian Schmitt then hired the entire Herrin crew to build the cat in aluminium. Brian then fitted the build shed out with tools computers etc. The team purchased raw aluminium ingots in 10,000-pound increments at commodity prices. The ingots then had to go to a smelter to make the 8-foot-wide, 35-foot-long sheets used for the transverse bulkheads. More than 12,000 parts were cut from aluminium sheets of various thicknesses. Each part received a serial number so they could trace it back to the original ingot should they need to hunt down any irregularities. All told, the project will require more than 140,000 pounds of aluminium to construct. They started by laying the keels, which are 76 mm inches thick, 203 mm high and 110 feet long pieces of aluminum. The keels were laid in 2017, and then the crew began installing the frames and bulkheads every 3 foot with the deck structure like an erector set. The hull bottoms are 8 mm for the aft 66% of the bottom with 9.5 mm in the forward 34% of the bottom, the hull sides are 6.4 mm, the aft part of the underwing is 6.4 mm, the forward part of the underwing is 8 mm. The deck is mainly 6.4 mm with the foredeck is 8 mm plate. The are T section stringers used longitudinally through the design. The x ray jpeg gives the idea. The vessel painting had commenced having been shot with chromate and two layers of epoxy before approximately 500 gal (1,893 l) of fairing compound and 325 gal (1,230 l) of various primers rendered the surface fair and ready for a yacht-quality Alexseal paint job with 35 gal (132.5 l) light ivory, 24 gal (91 gal) stark white, and 2 gal (7.6 l) cordovan gold. Parallel to the exterior, construction was on the home stretch with installation of the crew quarters and the saloon overhead. On the systems side, pressure checks were performed for hydraulics and plumbing.

Schmitt wanted a wooden interior and purchased 10,000 square feet of mahogany and brought in expert craftsman John Lombardi to run the wood shop. After 5 years into the project, the hull is now in primed, the engines, gensets, solar panels and most of the other systems are in place. And through it all, Schmitt maintained control, as he funded the shop and the men putting his dream together. To dampen vibrations, Herrin said he used Roxul, a lightweight, semi-rigid stone-wool insulation for fire resistance and sound control. His crew also sprayed cavities with Dow Froth-Pak, a quick-cure polyurethane foam for thermal insulation, and installed Sylomer (a microcellular PUR-elastomer) between the structural components and the floors, walls, and panels. “We glued the Sylomer, which is kind of a spongy foam, to the structure of the boat, and then the plywood of the subfloors and walls are glued to that,” Herrin explained, adding that this created a floating interior without any fasteners. The plywood, called QuietCore, is a composite sandwich panel comprising marine plywood skins and an acoustic damping layer that converts acoustic energy into small amounts of heat that are dissipated. Soundown claims that an 18mm (0.7“) QuietCore bulkhead can reduce noise transmission by up to 10 dBA, an audible reduction 50% greater than with regular marine plywood of equal thickness.

This boat is a very interesting design and build but shows the sort of resources and management skills required to bring a large project of this size together. Don’t ask the cost. But Brian will achieve his dream, I hope he enjoys it. The jpegs give the idea.

 

Aluminium as a multihull build material is good but it suffers from a few limitations. Although it is strong for its weight, in thin panels it can buckle or dent if it does not have sufficient framing/stringers available. It also has a limitation of about 3 mm minimum thickness for an average welder to get reasonable weld without rippling etc. Very thin aluminium can be welded ripple free by experts but it requires specialist equipment etc to get it done well. The large advantage of aluminium is wood working tools can be used to cut it and partially shape it. Metal work gear can be used to bend it etc, only the welding requires special equipment. The down side is high strength corrosion resistant aluminium losses its temper (manufactured strength processing) when welded by an average person. Upside is some aluminium boats have been glued together with special preparation and epoxies. Many smaller “tinnies” power boats are rivetted together but beware as over time the rivets work lose and small leaks can appear. A major advantage of boats with 6062 T6 or 6083 is you don’t have to paint them for sailing but a major downside is anodes are required and no dissimilar metals can be direct contact with one another as electrical currents can dissolve the aluminium. In aluminium , one needs insulation and interior panels to cover the interior where as most other materials except metal don’t need a full insulation layer and some materials don’t require an interior material coverings.

OK, so why write this piece? Because yesterday we got some details about a 110 foot 330,000 lbs aluminium catamaran with 8 mm bottoms and 6.4 mm sides in aluminium with decks of mainly of 6.4 mm. There is a lot of frames bulkheads and stringers. Compare this to Banana Split a 1989 42 x 21.5 foot catamaran designed by Michel Joubert and Bernard Nivelt and built by Prometa shipyard, in thick plate aluminium (Strongall process). This cat displaces about 30,000 lbs loaded. The hull bottom is 12 mm thick and the hull sides 10 mm, the decks and cabin are 8 or 10 mm aluminium with minimal framing. Banana Split is less than 10% of the displacement of H-2 but Banana Split has 50% thicker aluminium in the hulls and decks. Translation. Banana Split is incredibly strong for its size and displacement. It may have minimal framing but even so it is very strongly built. Later versions of this cat had reduced skin thicknesses and some stringers and framing. But we are still taking 10 mm bottoms and 8 mm sides.

Interesting. Let’s look at some other designs. Mooloolaba Fire Truck is a 50 x 42 foot trimaran that displaces 8,000 lbs and uses 5 mm thick aluminium with minimal framing in all 3 hulls. If you have the right round bilge and deck shape you can build very lightly in aluminium as demonstrated by Mooloolaba Fire Truck. The Fire Truck started as a racer but now is a cruiser with a larger main cabin.

Next is the Crowther 85 that is 50 x 24 foot displacing about 30,000 lbs that has 4.5 mm bottom plate and 4 mm topside with 3 mm deck and cabin plate. All of this is backed by 115 x 50 x 5 T frames at 1200 mm c/l. Stringers are 50 x 50 x 4.5 T section stringers at 225 mm c/l.

Finally for this group there is the Seahound catamaran 36 x 19 foot with a displacement of 20,000 lbs that uses 2.5 mm hull and deck aluminium backed by 3 mm L shaped aluminium frames and stringers.

What is being said here is that aluminium if correctly designed can be a very effective built material for multihulls from 30 foot to 200 foot. If you understand the material characteristics of aluminium and multihull round bilge shapes hull shapes you can use “thicker” (that does not mean 12 mm, more like 6.4 mm) aluminium with a minimal amount of framing and stringers to build a monocoque structure, of say a 40 foot cat, that can be built very rapidly. The Lex Nichol 50 foot Mooloolaba Fire Truck was built in less than a year as a side project for some spar makers.

Finally, remember the shell of EG a cat represents only 35% of a build. The dollar and time savings on EG paint will be offset by the additional cost of insulation, interior fitout and anode protection etc. But an aluminium shell can be built quickly with simple tools if you have the welding skills. The jpegs give the idea.

 

Hi oldmulti, it's now February 2024.
I can't get to the trimaranKits website! I've been trying for several days without success. Does this work for you?
Thanks in advance.

 

Polou. I have tried the site, I get the following response. Trimarankits is under the control of a trojan and my security software does not allow me to visit the site. The site was bad for a while returned and now appears to have disappeared. Wayne Barrett the designer would be 70 plus years old and may have retired although in 2021 he was still talking about doing another boat. I suggest you try the Wayback machine or google some of the articles on the web about Wayne and his plans.

Finally you could email ATL composites Australia who still promote Wayne designs to see if he is still contactable. The web address for ATL is: ATL Composites https://atlcomposites.com.au/page/contact

 

Don’t know if this is the right place to ask my question,
Is there information about this Kelsall 32 ?

 

Thank you very much oldmulti, no problem, I just wanted to visit Wayne's site to see if there was anything new.
I would like to build myself a trimaran in the style of the M60.
I also like R Kendrick's Scarabs but was looking for newer plans.

 

Composites are the option of choice for most multihulls now, with designers using various techniques to estimate the structures for boat. They range from experience and not much technology to designers who have to meet full EG ABS specifications for charter certification. There are some designers who are on the leading edge of light weight racing designs or home build plans that have no technical qualifications but do some experimentation to find a practical solution.

I know 2 guys who have 36 and 38 foot lightweight cruiser racer trimarans that have 330 gsm cloth in epoxy either side of 12 mm foam that is doubled over the bottom of the main hulls. These boats are still sailing over 30 years later. Neither designer used maths, just built them with a philosophy of if it did not break it was OK, if it did break strengthen it.

The next level of designer is one who uses some basic design software for composite construction. It breaks into 2 components. The EG ABS rules and the software many companies have to meet the ABS requirements. The next component is software that focuses on composite structures that have a variety of fabric, core and resin options to provide a composite that will meet your criteria of stiffness, strength and ability to with stand puncture resistance, wave impact etc. (Sorry, I am using simple terms here to try and explain the structure).

An example is: COMPOSITE STAR is all-embracing composite design software and database for engineers working with composite materials. It calculates:
* the mechanical properties of plies by micromechanics
* the mechanical and hygrothermal properties of laminates by Classical Laminate Theory (CLT)
* loaded ply / laminate mechanical and hygrothermal stresses/ strains
* Ply / laminate failure predictions with your choice of several different industry-standard and new failure criterion and progressive failure models.
Composite Star will take the mystery out of composite material properties, with accurate predictions of the strength, stiffness and behaviour under load for ANY combination of fibre, resin and cores and any laminate stacking sequences.
Composite Star can store and organise the material properties for all the fibres, resins, plies, and laminates that you use. These are kept in a single, easy-to-use database which plugs seamlessly into the laminate calculation engine.

From Reinforced Plastics.com: The company’s YACHTScant sail and motor boat scantling software, which could help accelerate yacht design processes and reduce time to market. The software includes materials and plies management, laminate evaluation by means of extended classical laminate theory (CLT) and scantling certification such as ISO ISO12215 Part 5. The integrated approach in CompoSIDE provides a centralised platform covering conceptual to detailed design of composite parts and structures. ‘By adopting CompoSIDE, we are able to accurately design and predict the structural performance of a part or yacht structure,’ said Torsten Conradi, CEO of judel/vrolijk.

The next level is FEA software to predict load paths, stress points etc Finite Element Analysis depends very much on a correct understanding of the loads that are going to impact a structure. This is very much good input data equals good output information. When you understand your potential stress points etc you can use then apply your composite analysis to find an appropriate composite layup to meet the needs. To give you an idea of the software options available to do the full analysis of a structure you can look at software from Plymouth University in the UK. The web page is: Composites ~ software https://ecm-academics.plymouth.ac.uk/jsummerscales/composites/software.php

COMPOSITES SOFTWARE
Environmental, including Life Cycle Assessment (LCA)
Finite Element Analysis (FEA)
General Software
Image Processing and Analysis
Laminate Analysis
Modelling Textiles including braid calculator
Process Modelling (Filament winding and tapelaying)
Process Modelling (Resin Transfer Moulding)
Process Modelling (Thermoplastic Matrix Composites)

General Software
Adhesives Design Toolkit (National Physical Laboratory ).
Aero Optimal
AnalySwift SwiftComp (models composites as easily as metals, for quick virtual testing or as a plug-in for FEA)
AnalySwift VABS (enables rigorous composite blade/beam modeling)
Autodesk Simulation Composite Design
BMI3: Buckling Mode Interaction Program
CompoSIDE: web-based integrated design platform with a material database and laminate stack analysis, FE application and other functionalities
Composite OracleTM
Composite Star 2.0 (free 30-day trial to download - "all-embracing composite design software and database for composite materials and structures")
Composites Design and Manufacturing HUB
Engidesk: "toolbox for the design and analysis of composite structures"
EuCIA Eco Impact Calculator
Fibreline Composites Calculation Program (registration required: electronic calculation of the load-carrying capacity of construction profiles for beams and columns)
FiberSIM (integrated software for composite design and manufacturing)
Fibrify: define optimal fiber designs through integrated FEA simulation tools ~ control, monitor and manage equipment in real-time.
InCA Intelligent Cost Analysis® (models the production environment using cost as the measure for optimisation)
Laminate Tools (Design-Analysis-Check-Manufacture)
Mechanical Engineering Calculations (MechEng Computing LLC)
Process and Mechanical Modelling of Engineering Composites (Anthony Pickett)

The author tried to use only software that is ‘free’ for students to experiment with these codes.
Simulayt (integrated design, analysis and manufacture of structures made from fibre reinforced materials)

The above is just one organization available software to do an analysis of a hull structure and potential layup options for a design. Relevance, a company like VLPL can do a full design structural analysis, provide layup options, do a build sequence, mould design, production process design and engineering etc for any boat. The only limitation is the amount of money you have for the design process.

What really is being said here is a designer with a lot of experience can design a boat with a minimum of technology but often it is conservative or designed for a client who is willing to modify it if required. The other end of scale is the design firms who have high technology and can design the boat in detail before any real work is done. But be warned, both techniques can still lead to failure. No technology may not understand a stress point, high technology may have inputed incorrect base data. Then any designer is only the designer, if a builder says I can save money by substituting a cheaper fabric or a different foam then all the experience or technology in the world may not be able to save the boat. Finally next time you hit a pier see what damage you have done because boats that are not well maintained are not the responsibility of a designer.

Sorry about the limited jpegs. The jpegs are not recommendations just an example of what available.

 

Hi. Wild Thing, the Tennant trimaran has been purchased recently in Canada and the new owner needs some help. If anyone knows about Tennants Wild Thing tri's could you go to the Malclom Tennat "Wild Thing" Tri thread.

 

China is building many boats now and are prepared to build from 1 yacht to 10000 yachts for you at an often low price. But you have to very careful, understanding what you are going to get for your money. China will build exactly what you specify but its up to you to ensure that you have specified what you expect. Do not assume that a charter “fiberglass catamaran” will be built using foam e-glass vinylester as the build material. Depending on the manufacturer you may end up with a solid polyester glass structure that may or may not meet EG ABS rules. As I said, understand what you want and ensure it is built to that standard.

Qingdao Bestyear Hardware & Machinery Co., Ltd. specializes in boats and valves exports, and is one of the leading manufacturer and export companies in China. Boats are the main business scope, exporting boats for over 20 years. They have professional and technical engineers. The types of boats they produce vary from RIB boat (2.4M to 11M), GRP Speed boat, Inflatable boat, Luxury Yacht, Aluminum alloy boat, steel boats and some sailing yachts including multihulls.

The Bestyear 33 foot Fiberglass Catamaran is sailing vessel for charter for up to 35 passengers. The price for the basic catamaran shell is $US 55,000.

The Bestyear 33 is 32.8 x 18 foot with a weight of 6,940 lbs. 35 passengers imply a payload capacity of 6,500 lbs for a total displacement of 13,500 lbs. The 46 foot mast carries a 339 square foot mainsail and a 150 square foot jib. The limited jpegs give the idea the hulls are relatively slim and looks about a length to beam of 10 to1. The draft is listed as 1.2 foot minimum and 1.6 foot over the rudder and a “depth” of 3.1 foot. No mention of a keel of any format. The 60HP 4-stroke engine outboard engine may give a hint that this is a motor sailor more than an outright sailing cat. I think this cat can sail OK but as a charter cat it has to meet schedules with an engine.

The build is described as fiberglass with no other details. I know of solid fiberglass skin cats of this size, but if they are built to EG ABS standards they tend to be heavy. Sorry I cannot give any further structural detail.

Bestyear also produce a 30 foot version of a charter catamaran that is 30 x 14 foot that is listed as a Sailing motor boat. That is the last jpeg.

There are limited jpegs and no performance reports but several appear to have been produced.

 

Had a quick look on the Way Back machine and found the following
https://web.archive.org/web/20210701122819/https://trimarankit.com/
There is a contact number and email in the top right hand corner. Hope this helps