H2

Design Criteria

H2 is a handsome 33.5 meter aluminum power catamaran designed by Marples Marine and is being built by Catman Cats. It has been conceived for both luxury cruising and long-range expeditions to remote areas of the world including ice belt regions.

The twin hulls will provide an incredibly stable and comfortable platform for passengers and crew, while the slender hull forms are designed for maximum fuel efficiency and to reduce wave making drag. The 5 foot draft will allow the vessel to enter most anchorages and the high underwing clearance is designed to allow full speed operation in moderate sea conditions with a full load.

Construction of an Aluminum Power Catamaran

Van Gorkom Yacht Design was brought into this project to engineer and detail the yacht’s structures. All structural components, plating, frames and foundations have been modelled in 3D so as to precisely gauge their geometry for the cutting files sent to the mill. This has allowed the builder to efficiently erect and weld up the structure months ahead of the building schedule. The model has also been key in accurately determining overall construction weights and their distribution.

H2’s robust construction has been engineered for potential operations in moderate ice conditions with the emphasis on extra framing and strengthened ice belts. It will be of aluminum plate (alloy 5083-H32) and extruded shapes (alloy 6061-T6). All scantlings, materials and weldment will be sized to comply with the American Bureau of Shipping’s (ABS) ‘Motor Pleasure Yachts’ design guidelines 2016. Construction of the aluminum power catamaran began in September, 2017.

Passenger Accommodations

The 4-deck arrangement includes one owner’s stateroom, three guest cabins, and accommodations for four to six crew members. The three tastefully appointed guest cabins on the main deck have queen size beds, private bathrooms, and are accessed from the main passageway connected to the salon area and foredeck. There is also a study/library with a head attached.

The spacious aluminum power catamaran’s salon features full-height “aquarium” windows offering spectacular views on the port side, and a double-door walk-out onto the main deck on the starboard side. The adjoining gourmet galley and bar area is fully equipped with a refrigerator and bottom load freezer, a restaurant-style stove, a dishwasher, a trash compactor, a microwave/convection oven, and a wine cooler.

Access to dive locker/equipment room, aft of the salon, is from the aft main deck. This area also features a stowable dining table for ten and a fully integrated barbecue unit with a refrigerator and storage space. Exterior port and starboard stairs lead down to the swim platforms and transom access to the hulls.

The upper deck consists of the helideck and pilot house, which includes a master stateroom, bridge and day-head. The generous master cabin has a queen bed, his-and-hers (walk-in) closets, a chest of drawers, an entertainment cabinet, and a spacious en-suite bathroom. The well-equipped bridge has ample room for the crew and guests. Optional wing station controls are fitted on the Portuguese bridge. The fourth level, partially covered flybridge offers a 360 degree field of vision.

Access to the crew quarters located in the hulls will be from the main deck cabin area and through the watertight transom door that opens to the swim platform. The crew’s quarters will have three staterooms, a crew galley and dinette and two crew bathrooms. Air conditioning will be provided in all enclosed areas including machinery spaces.

Performance

In order to achieve a high level of confidence in the choice of power plants and propellers for H2, Marples Marine contracted HydroComp, Inc. to perform an in-depth analysis of the vessels hydrodynamic and performance characteristics. Using advanced modeling software they were able to develop a set of resistance and power curves that closely described the required propulsion system criteria, and facilitated the propulsor design.

Additionally, an analysis was made of existing aluminum power catamaran designs and other published data which gave conformation to the intended speeds and power ranges. The designers have high confidence that the quoted speeds will be met with the installed power for the displacement of the vessel. During the final design phase, the speed and power prediction effort will continue to be monitored.

The eventual choice of engines was the MTU V2000-M96 marine diesel engine running at about 75% rated horsepower for a nominal cruise speed of 15 to 18 knots. A long range cruise speed of 13-15 knots will provide an estimated range of 4800 Nm assuming normal consumption rates. The boat speed at full power is estimated to be 20-22 knots. The power trains will feature thrust bearings and anti-vibration components. The propellers will be 36” diameter 5 blades wheels. There will also be fore and aft thrusters for maneuvering.

Outfitting an Aluminum Power Catamaran

H2 will be designed for a standard of construction and outfitting consistent with the owner’s specifications and guidelines of the American Boat and Yacht Council (ABYC), National Fire Protection Association (NFPA), American Bureau of Shipping (ABS), and the Code of Federal Regulations (CFR) where appropriate.

Safety equipment will comply or exceed with ABYC standards, which provides guidelines for pleasure vessels. This will include portable fire extinguishers in all passenger areas, manual and automatic fire control systems in all machinery and tank spaces, including the helideck. Bilges will be fitted with manual and automatic pumping systems along with high water bilge alarms.

House power will come from two 20kw generators producing 110 volts and 240 volts and charging a series of house and starter batteries. H2 will have twin anchoring systems with electric powered windlasses. Two windlasses on the after deck will assist with docking procedures.

Fuel tankage will be integral and meet the guidelines of the ABS. Waste and waste oil tanks will be separate and have deck pump-out fittings. Potable water tanks will be separate and be fed by deck fittings and water makers.

H2 will carry an 8 meter long deep-V tender with twin 150hp outboard motors. This will be stowed on the main deck and launched with twin retractable davits. This vessel will also carry a 4 meter RIB powered by a 35hp outboard that will be stowed in chocks on the helideck. A compact car, ATV or snow mobile can be loaded onto the main deck with the crane that stows away neatly into the helideck. In addition, H2 will carry an R44 Robinson rotary wing aircraft launched from the helideck. Fixed wing amphibians can also be accommodated using the deck crane for launching.

As featured in Professional Boatbuilder – An Aluminum Expedition Catamaran – Professional BoatBuilder Magazine (proboat.com).