A New Era of Sustainable Ecotourism Through Design Optimization of Whale Watching Vessels

Author: Nic de Waal, Managing Director,Teknicraft Design

Based in New Zealand on the Kaikōura Peninsula, Whale Watch provides sustainable ecotourism services for exploring and observing whales, dolphins, seals, and other mammals in their natural habitat. The tour company champions ecological preservation by using vessels specifically designed and constructed to operate in harmony with the mammals and their marine environment.

In their early years of operation, Whale Watch used a rigid hull inflatable, but in 1999 local naval architects, Teknicraft, designed their first catamaran to specifically address the requirements of excellent ride comfort and low fuel consumption combined with a superstructure arrangement suited for whale watching tours. Since the whales could be anything between 5 nautical miles and 30 nautical miles offshore on any given day, a vessel with high speed was required to spend the minimum time transiting and maximum time observing whales.

The Kaikōura Peninsula is directly exposed to the Pacific Ocean with no natural barriers, and back in the day the small, semi-protected natural harbor offered only limited space for vessel moorings during the day. This meant sightseeing craft had to be relatively small, challenging the requirements of a vessel that needed to operate in the seaways of the open ocean.

Teknicraft’s solution for these challenges was a 17m-catamaran hull with hydrofoil support that provided lift to reduce pressure and friction resistance, while providing motion damping to increase the seakeeping and ride qualities.

Following the success of the first catamaran, a further five sister ships were built over the ensuing years. As the Whale Watch operation began to expand dramatically, larger vessels were discussed, but the depth and size of the natural harbor remained a limitation.

However, in November 2016, a massive earthquake hit the region, causing large parts of the shoreline to rise by approximately 1m, including the Kaikōura harbor. This overnight reduction in the water depth inside the harbor made it impossible for the fleet to operate. With government support, an extensive re-build of the Kaikōura harbor followed, making it larger and deeper and ensuring that it was now suitable for larger vessels. The deeper harbor presented new opportunities to Whale Watch, and Teknicraft was again commissioned, this time designing a larger, 24m-vessel that could operate at speeds between 30 and 35 knots, while carrying 120 passengers.

For their post earthquake design Teknicraft decided to use Quad Hamilton HJ364 jet units because they are quieter for marine mammals compared with other forms of propulsion. Their propellers are also internal, so the risk of a propeller strike with marine mammals is completely eliminated.

They retained the hydrofoil support system, however the new foil was made adjustable in terms of its angle of attack. This control directly results in lower net fuel consumption as the foil can be set to its most effective position to suit different passenger and fuel loadings, as well as different operating speeds and sea conditions.

Teknicraft used Omnis Marine for the optimization of the hull and the foil system. As the service speed of the new design operates at a high Froude number of 1.2, an initial calibration study was undertaken to align sea trial data from the 17m design with the parameters to be used in the simulations for the new vessel. Curve, surface and box refinements were used to ensure the required resolution was achieved to capture potentially complex turbulence formations in the region of the foil, chine and transom wakes, and a higher than normal mesh diffusion was used in the domain.

A very successful alignment of the simulation data with the 17m sea trial data within 1% gave Teknicraft a high degree of confidence and understanding to run a design optimization study for the new catamaran.

Whale Watch’s new 24m cat was launched in October 2020 and heralds in a new era of sustainable ecotourism for this innovative marine tourism operator. Omnis Marine has played a significant part in the design’s evolution, and the whole visitor experience will be heightened by this larger, more configurable and more comfortable vessel.