The Rinjani 13.8 is designed as a fuel efficient power catamaran with a top speed of 16 knots whilst being most efficient in the 12 – 14 knot cruising speed range.
Originally the owner wanted a boat similar to the 11 metre Whitehaven sailing catamaran Sengiggi Sensation built by Wayne Furler in Lombok with a similar layout but as a power cat. The resulting design grew to 13.8 metres but retains the elegance and efficiency on the sailing designs.
See more construction photos here.
General Layout and Accommodation
There are 2 large double cabins forward of the main bulkhead with berths that are 1.6 m wide (5’ 4”). The flair on the outer side of the hulls allows for a seat on the outer side, shelf and or hanging locker. Forward in the hulls can be a single berth or a bathroom. In the standard layout the galley is positioned up in the main saloon as is the navigation station.
There are many options available to the individual owner and the galley or navigation station can be in the hulls. Any layout is possible between the four main bulkheads. Aft in the starboard hull is a large bathroom with a double berth aft in the port hull. The saloon opens onto the aft deck cockpit area via a large sliding door. There may be a small table in this area or it can be left open. Across the back of the aft deck is a large comfortable lounge seat. The flybridge encompasses the helm station forward with a lounging area aft.
Engines and Hull Shape
Early on in the design process it was decided that an important criteria of the design would be fuel efficiency at a comfortable cruising speed of 12 – 14 knots. Twin 75 hp Yanmar Saildrives were chosen for the engines with the hull shape being more of a modified sailing catamaran shape rather than a brutish power catamaran shape. The resultant hull shape has low wetted surface area with a high prismatic coefficient and is expected to use no more than a litre a mile at 10 knots. With this configuration the engines are aft in their own engine compartment with large swim steps behind the engine compartment. There is also a skeg forward of the propellers to provide protection for the propellers and the rudders.
Construction
Construction of the hulls, foredecks and decks outboard of the hull centerline are of strip plank 16 mm Western Red Cedar (WRC) and a combination of 600 and 800 gr/m2 Double Bias f/glass and 750 gr/m2 Triaxial f/glass. The remaining deck areas, underwing and cockpit surfaces are all composite foam sandwich construction. Main full width bulkheads are strip plank WRC composite construction. Unidirectional Fibreglass is used strategically in the underwing, main bulkheads and deck laminate to provide strength and stiffness where required. Epoxy resins are used through-out.
Specifications
| LOA | 13.86 m (45’ 6”) | Draft | ||
| LWL | 13.55 m (44’ 6”) | Hull | 490 mm (1’ 7”) | |
| BOA | 6.55 m (21’ 6”) | Rudders/keel | 740 mm (2’ 5”) | |
| BCL | 5.0 m (16’ 4”) | |
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| Hull BWL | 914 mm | Headroom |
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| Hull LWL : Hull BWL |
14.8 : 1 | Hulls | 2.00 m | |
| Saloon | 2.00 m |
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| Displacement | ||||
| DWL | 6970 kg | Underwing Clearance | 750 mm – 920 mm |