At the Gothenburg HSBO High Speed Boat Operators Forum, the Oslo Boat Show, and the recent Monaco Yacht Show, the Iceland-based Rafnar shipyard presented and launched two new products based upon the innovative Rafnar OK Hull & Keel technology. This previously little-known Icelandic shipyard and design team continue to surprise the market with their amazingly stable OK Hull & Keel technology, and 2017 promises to bring to market even more interesting and innovative versions of their product range.
The 8,5-metre Flengur 850 Special Services Support RIB
After a specific request from the Icelandic Coastguard organisation – who have already had an 11-metre Leiftur 1100 Cabin RIB in operational service for the past year, and who found that the performance of the Rafnar OK hull has drastically improved their operational capabilities in rough and harsh conditions – the Rafnar team have recently delivered an easily deployable 8,5m Special Service Open RIB for rapid response use from the coastguard mother-ship. This compact and fast RIB is jet-driven, using a Volvo Penta D6 330HP engine which powers a single MJP Ultrajet 251HT, and reaches 30 knots. The patented OK Hull technology is scaled down for this size requirement, and the RIB performs with the same comfort and stability as her bigger sisters.
The coastguard specifically required that this craft could be easily deployed both from the coastguard cutter, and also from a C130 aircraft by parachute when required, so all detail was focused on simplicity, ruggedness, and reliability. With an enthusiastic response from the operational teams in the coastguard, Rafnar have now introduced this craft as a general purpose service tender and work-boat for commercial and leisure usage in the mega-yacht support market.
The 12-metre Leiknir 1200 DayCruiser
During 2015 Rafnar tested a bold prototype of a scaled-up 11m coastguard and search-and-rescue hull carrying two 500 HP Marinediesel inboard engines with Konrad drives, which achieved 42 knots top speed. This evolved into the ‘Leiknir 1200 Open Support Craft’, with solid foam-collar fendering, instead of standard inflatable pontoons. The dynamic performance of this much heavier and voluminous ‘open’ craft prompted the Rafnar designers to design and build a Nordic DayCruiser on this hull platform.
Selecting to carry out this build aimed at the leisure market at the Rafnar-owned facility in Maloy, in Norway, the Rafnar team specifically targeted the Norwegian boat enthusiast with the design and capability of this fast and comfortable boat. Instead of the Marinediesel option previously applied to this hull-type, designers decided upon dual Volvo Penta IPS 435 HP propulsion. Incorporating a spacious fore-cabin, a shower and head, a vast enclosed pilot-house, and domestic cooking facilities, this attractive day-cruiser/over-nighter provides an ideal exploration platform for the Nordic fjords and archipelagos. With a top speed of 35 knots and an extensive range, the 12m ‘Leiknir 1200 DayCruiser’ greatly broadens the scope of the core stated Rafnar philosophy ‘Keeping Comfort at Sea’.
As a ‘warm-weather’ version of this attractive 12m craft, the design team has now been commissioned to produce both a ‘Half-open’ cabin version, and a ‘T-Top’ open version for use in the Mediterranean and Caribbean. The increase in interior volume with this 12m hull-form has allowed Rafnar to successfully fit two inboard engines, however an outboard open version is also in design – where the recommended choice will be for 2 x 400 HP outboard motors, aiming to achieve a speed of 50 knots.
Scaling up to 38-metre with a Long Distance Explorer Yacht
Recent CFD –fluid-dynamics – testing has indicated that the OK Hull technology is scalable even farther, and the designer and inventor, Ossur Kristinsson, has completed the design of a luxury 38m super-yacht, in collaboration with Cano Lanza Yacht Design. Although not yet in build, this explorer yacht promises to demonstrate all of the comfort and hull-performance features and characteristics of the Rafnar RIBs, open boats, and day-cruiser.
The unique OK hull-form, which appears to ‘invite’ the resistant displaced water around it to travel more swiftly and efficiently along the hull, has surprised many a mariner and naval architect by its simplicity and effectiveness – with no gimmicks or gadgets being applied so as to achieve this vastly improved performance. The Rafnar hull performs in displacement-type mode at all times, and crew experience little or no slamming and bouncing or instability, even in rough conditions.
