Featuring a 9.7m stepped tri-hull, an aerodynamic cabin top and deck, and a pair of Suzuki DS350s, S.J. Seahawk pushes the boundaries of trailer-boat capabilities.
We met S.J. Seahawk’s owner and designer, Phillip Morris, at Wellington’s Seaview Marina on a warm late-spring afternoon, with a 10-knot breeze driving a light chop. We wanted more chop and as it turned out, so did the boat.
Manoeuvring around the marina, this boat handles very much like a smaller vessel, with one useful difference. There is a wide gap between the outboards, so steering via the throttles works very nicely.
Out on the harbour, the first thing we noticed was acceleration. Lots of it. There’s no climbing onto a bow-wave or powering out of a hole. This thing just goes. Directly into the chop from a standing start, we saw 32 knots in 9.5 seconds and a top speed slightly north of 54 knots (100kph).
Phil built this boat for sport-fishing the Wairarapa Coast. Cruising at 3,800rpm (30-35 knots depending on weather), his crew can reach Cape Palliser an hour after leaving Seaview Marina. Fishing out there, you need a boat that can get home fast. The area cuts up quickly, and you need to reach Fitzroy Bay before the Turakirae Head wind factory hits full production.
We were disappointed that we couldn’t run hard into a big chop. The bow on S.J. Seahawk looks sharp enough to cut bait and we expected a softish landing. Phil’s design target speed was 50 knots plus. The technical consultants at Suzuki Marine thought that was a bit optimistic. Based on S.J. Seahawk’s size and weight, they recommended 19-inch propellers suitable for a top speed of about 45 knots. First time out, the engines revved off the spec sheet.
Graham Kennedy of Suzuki Marine explains that the hull traps a lot of air, which makes it exceptionally efficient (slippery). In addition, the rounded cabin top cuts air resistance, and the top-mounted wing generates about half a tonne of lift at 54 knots, reducing the boat’s effective weight. With 25.5-inch props the boat still seems slightly under-propped. That’s great! It means the added weight of a really big fish won’t hurt the boat’s performance.
Phil reckons the wing reduces rolling. To verify the wing’s performance, Phil and his team mounted the wing on the back of a truck and drove along the Wellington motorway, monitoring the lift with electronic scales. They got some interesting looks.
On board, we were having a lot of fun. At 50-plus knots there was no thumping or jarring from the near half-metre chop, only a bit of hull noise to prove you were crushing waves. The foam-cored carbon fibre top is rock-solid. The forward seats provide plenty of side support, deep padding, and well-positioned footrests. With plenty of grab-rails, this boat delivers a comfortable ride whether you’re sitting or standing.
The steering system adapts to the power level, becoming less touchy as the speed/power increases. Below about 25 knots the turning circle is only
a few boat-lengths: Above 30 knots, the turning circle grows massively. Phil explained that the system can be programmed to deliver tighter turns at speed.
One aspect takes a bit of getting used to: unlike a monohull, this boat leans outward in turns.
Running over our own wake gave a good idea of how this boat will handle a quartering following sea. There’s a quick rolling motion as the sponsons walk their way down the chop. In spite of that, the boat holds its course well.
Designed as a dedicated sport-fisher, S.J. Seahawk’s cockpit has more than enough room for four or five fishos. The side-decks have plenty of rod holders and grabrails that are as good looking as they are functional. Wide full-length side panels allow stand-up fishos to brace themselves when fighting Wairarapa Coast monsters. A wide transom door gives access to a full width platform forward of the engines. The boarding ladder doubles as a safety rail across the aft edge of the platform. When deployed, the bottom rung is deep enough to be useable even in rough water. Bait stations either side of the transom door feature yet more rod holders. Those bait stations are far enough inboard that they don’t interfere with docklines made fast to the aft mooring cleats.
The cockpit is fully watertight, with a bulkhead between the small cabin and the helm station. The outward opening transom door has drain holes, and opens easily when needed. The cockpit floor has fixings to accommodate custom-built units such as a dive-bottle rack or extra seating.
The deck and cabin top is a one-piece foam-cored carbon-fibre composite unit that weighs all of 63kg. Near the aft end of the dodger, a hefty alloy frame supports the cabin top. This frame also takes the half-tonne lift from the wing and supports the trolling outriggers mounted on the sides. When trolling, Phil and his team also use a centre-rigger.
Before building S.J. Seahawk, a 3D model of the boat was developed in Solidworks. This allowed Phil and his team to check the headroom. The end result is that there’s no risk of accidentally banging your head inside this boat. The carpet-lined dodger is completely smooth, apart from the alloy hoop frame, which is high enough not to pose a threat.
S.J. Seahawk’s anchor is fully accessible and operable via two hatches in the cabin, but there should be no need to go up on the foredeck in normal circumstances. However, it’s not too difficult to get up forward. The decks have great non-skid, and the grabrails and outer rail are made of large diameter tubing that’s great for getting a really strong grip. We would have liked a grabrail on the back of the dodger. The grabrails on the dodger top and cabin top could do with more clearance for the fingers, and it’s a bit of a tight squeeze getting up onto the side deck.
S.J. Seahawk is a development of the 7.6m Eliminator, which Phil and his team built 26 years ago. Out on the water, it was clear that the new boat embodies a lot of lessons learned from all that time spent fishing on the old boat. We were rapt to discover that Phil had saved the best for last. As we approached the ramp, Phil’s mate backed the trailer down until the ute’s drawbar was just short of the water’s edge. Those Suzukis stayed in gear as we cruised toward the trailer. Once the bow passed between the side guides Phil gave her a bit of throttle and she slid right up the trailer. A loud click from the boat lock signalled that she was secure.
On the trailer, the boat is surprisingly high above the ground. Phil explains that this allows him to drive on without tilting the motors. “You lose steerage if you tilt the motors,” he said. Phil launched his previous boat at wild beaches like Ngawi, where there’s no second chance. You put the boat on the trailer, or you park it sideways. We asked if he planned to fish this boat out of Ngawi. “Probably,” he said, although this boat can reach Ngawi quicker on its own bottom than by road.
S.J. Seahawk’s three-axle trailer features stowage for the side guides, to keep it inside the 2.5m- wide road limit. The braking system has stainless steel rotors and calipers on all three axles, with an electronic control system that communicates with the braking system in the Dodge RAM 2500 ute. Testing for its certificate of fitness, the ute, trailer, and boat combo stopped in the same distance as the ute achieves with no trailer attached. The control system has separate trailer-brake settings for loaded and unloaded. And, if the trailer becomes detached, the control system applies the trailer brakes.
Phil’s ute has several features that help simplify towing such a big load. It has five cameras which adjust their angles and field of view when backing the trailer, and the proximity sensors also adapt to the trailer’s presence. When he first built S.J. Seahawk, he found that a petrol V8 RAM 1500 did the trick OK. However, the Cummins diesel in the 2500 is so much better that Phil found himself checking his wing mirrors to make sure he still had the boat on.
S.J. Seahawk will be trailered to fishing competitions around New Zealand. With enough fuel for a range of over 250 nautical miles, she can fish most popular New Zealand game-fishing spots on a day trip.
Morris Metal Products has been marketing powerboats under its ‘Eliminator’ brand for several years. It’s keen, and well-equipped, to custom-build more boats based on the S.J. Seahawk design. This boat first hit the water in late winter 2024, just in time for the southern bluefin tuna season. Phil and his team broke the ice with a solid 80kg southern bluefin. In addition to sport-fishing, the concept lends itself to a range of applications requiring a fast, economical trailer boat with heaps of cockpit space.
Did the thought of diesel powered outboards cross your mind during the build process
We will ask and come back to you.