An exciting new foil-assisted powercat, a collaboration between designer Scott Robson and renowned sailor Matt Mason, was recently completed by Allspec Marine in Nelson. Boating New Zealand joined the vessel for the last leg of its delivery voyage.
As we drove over the mist-shrouded Coromandel Ranges, I suspected it was going to be an eventful day. Brett Paterson and I had left Auckland at 4:00am to make Whitianga by 7:00am to meet up with a brand-new Scott Robson-designed foil-assisted powercat – model RMX 444.
444 is the length in feet and every one of them was needed to accommodate the owners’ detailed requirements: speed, economy, and fit for purpose; elegantly specified as suitable for grandkids and fishing; and, oh yes, styling that was distinctive.
We pulled up to the Whitianga Wharf right on time with About Time gently pulling on her lines against a rapidly incoming tide.
About Time was part-way through her first major trip after being built in Nelson by Allspec Marine. The owner and Project Manager Matt Mason were hopping up the coast in manageable bites. The previous day they had travelled around East Cape from Napier, making Whitianga for refuelling and a good night’s rest.
They were in great spirits and ready to get underway for our trip round the end of the Coromandel Peninsula and into home port Auckland. The boat looked purposeful and futuristic in a slightly understated manner: black cabin on top of white hulls, nice curves, and eyebrow-like hull windows to break up the hull height. The boat’s hull chines just visible.
She also looks very well-proportioned and it’s not until you see a person onboard that you get an idea of the scale of the boat. She’s big! And she needs to have some size to match the twin 600hp Mercury outboard motors.
Drop-down doors in the cockpit sides made alighting easy from the jetty when I loaded my camera equipment and some breakfast aboard. The wide cockpit is finished in Flexiteek and was very grippy in the morning dew. A Takacat tender was neatly stowed between the outboards, lashed to the stainless rails.
Inside the cabin, Matt turned on the Simrad instruments – three large 19-inch MFD displays glowing alongside the Mercury throttle controls. The motors started with a throaty roar before subsiding to a muted rumble, bubbles emanating from the exhaust. Ready to go, we cast off the lines, as an interested bystander took photos. Unfortunately, we left Brett ashore to drive the car back to Auckland, quipping that we’ll probably beat him home.
The weather forecast was a mixed bag with some heavy rain forecast but little wind. The rain was meant to be early, so if we were going to get any good photos with the drone we had to get it up right away.
The boat streaked out of Whitianga, leaving a flat wash trailing behind as we headed clear of the Whitianga Airfield no-fly zone. Once aloft, I raced the drone ahead to capture the cat at speed. It looked all a bit surreal – a black and white futuristic craft on a painted ocean of grey with an ill-defined horizon. The only distinctive feature was the bright wash trailing behind the boat. But unlike a displacement boat’s, this trail was devoid of waves and simply dissolved behind the boat.
The craft has a single machined titanium hydrofoil with vertical arms at each end attached to the hull. The foil can rotate around a pivot point driven by hydraulic actuators. This allows for fine adjustments to the angle of attack, which together with the hulls’ trim tabs, can be adjusted to optimise the ride for the conditions. The foil can be fully retracted to prevent fouling.
Optimisation can be for either economy or speed and it’s the same for the foil itself, with designs optimised for speed or economy. The owner has opted for economy since marginally more top end speed is not a priority for him. If you’re travelling at 47 knots economically, then the ability to hit 50 knots is probably not that significant? [Since this review, the vessel has achieved speeds in excess of 52 knots.]
We had to slow down to the low 30 knots so the drone could keep up, and when Matt opened the throttles, the boat quickly pulled away. It made for a great over the horizon shot, but I was a bit worried about leaving the drone behind with a low battery.
After the aerial photography we got down to setting a course up the coast and trimming the foil to get the best fuel economy. This coastal trip was part of the boat’s commissioning and getting to grips with how all the systems worked. Calibrating the foil was not straight forward as a key sensor measuring foil angle was not yet operational, so good old trial and error came into play.
Soon we were comfortably cruising at 35 knots. The sensation was like low flying – with the flat sea and the cloud and mist enveloping us, it felt quite weird. Like we were in our own world with no reference points to work out what direction we were headed. I needed a reassuring glance at the electronic chart to check we were actually on course and look at the radar to see the way ahead was clear.
The owner sitting in the port front seat had his eyes glued ahead looking for any foreign objects we might have to dodge, such as driftwood. This had happened a couple of times on the trip around East Cape.
Fuel consumption at 35 knots was 150 litres per hour (total from both engines). At 30 knots fuel burn is 130 litres per hour or 4.3 litres per nautical mile, so much the same as at 35 knots. The fuel tanks hold 1,900 litres which gives a 438 nautical mile range at 30 knots.
Underway the foil is always helping the boat, with an estimated peak lift of close to four tonnes. The boats hull rises approximately 300mm higher in the water than in non-foiling mode. The pictures at speed show this and this is no doubt the reason for the significant reduction in wake. Matt did a full circle turn at speed, and even with a tight turn, by the time we crossed our wake there was only flat water.
The outboard mounting has been designed to account for the changes in ride height and the propellers remain firmly embedded in good flow. At speed the noise of the outboards was minimal – we could have a decent conversation on the aft deck or inside with the cabin doors open.
In rougher weather while coming up the coast, Matt said the boat performed well. He said you had to drive it more, altering throttle when faced with larger waves, but good average speeds were easy to maintain: “One-metre 45o angled waves were no bother and speed was maintained at over 30 knots.”
Construction
The boat is constructed of fibreglass and foam with some carbon in the high load areas. It has watertight bulkheads in the hulls below floor level in case of any collision damage forward. Structural engineering was by PURE Design and Engineering.
The black windows fit seamlessly into the cabin top structure and enhance the sleek profile. Allspec Marine’s fit and finish is first class, with a nice light oak timber interior. The helm seats are upholstered in leather and provide great views through the all-round windows. Vision from the helm is excellent, also to the rear through glass sliding cabin doors. Overall, the interior imparts warm modern vibes.
Switching is all CZone, which with the rain on our trip was put to good use operating the large sweep windscreen wipers.
Below to starboard is the owner’s cabin forward with connected bathroom aft. The owners’ cabin has a large double walk around bed and nice lighting giving the cabin a warm glow. The bathroom is very large with a full-size, nicely finished separate shower with easy-clean surfaces.
The port hull has two cabins, one with three bunks forward and another with a double berth aft. These provide plenty of accommodation for the grandkids and guests.
Engines
I asked the owner why he chose Mercury 600hp outboards. He said that once they came onto the market it gave them the option to consider their use. There was
a minimum horsepower requirement for the craft, which the Mercury’s met, and he preferred their relative simplicity and space saving compared to inboard motor options.In the rare case where an engine might need replacement then it was a simple job to swap them out. Also, their quietness was a big plus.
The motors tilt up fully clear of the water when on the marina.
Foil design
The foil design was by Paul Bieker. In the world of high-performance sailing, few names are more synonymous with speed than Bieker’s and he is a sought-after expert. The Bieker Moth was sailed by the top six contestants in the 2021 Worlds. He also consulted to Luna Rossa in the recent AC37 series.
The foils were modelled by Paul Bieker using CFD (Computational Fluid Dynamics) to understand how the hull and foils interact. Scott Robson was pleased to hear from Paul that his hull design and foil placement was spot-on – no changes were required. The foils systems were engineered by Neil Wilkinson and Kerry Jones from Axis Precision CNC Ltd in Warkworth did the foil machining.
With the boat having a dry weight of 9.5 tonnes – 11 to 11.5 tonnes fully loaded – the foil assist of up to four tonnes reduces the effective displacement by around 35%.Fuel economy is improved by 33% with foil assisted technology confirmed by the initial sea trials at Nelson without the foil fitted.
On the cabin top there is the neatest solar panel installation I have seen – 1100 watts in total, feeding the lithium-ion battery system. Charging is shared between the Mercury engines and the solar array – no separate genset is required and 240 volts is available through an inverter.
Summing up
Using experienced industry professionals working at the top of their game in boat design, foil design and construction gave the owner a great deal of confidence that the boat would perform as expected. The owner said some of his friends considered he was taking quite a risk, but he feels vindicated by the finished article.
Our trip along the coast quickly put any doubts to rest, with a performance that was on the verge of magical. And yes, we did beat Brett driving back to Auckland!
After his journey to get the vessel of his dreams, the owner gets the final word: “I am happy– the boat is doing what
I want!”
About Time will be seen around the coast this summer. Keep an eye out for her, but be quick – she will likely disappear over the horizon in no time.
