In a departure from tradition, the latest Silver Tiger 9.5m catamaran to roll off the TDL Marine production line sports twin inboard diesels rather than the marque's more conventional outboards. The change, says Norman Holtzhausen, offers numerous advantages.
Silver Tiger cats – between eight and 12m in length – have a reputation for fuel efficiency and seaworthiness. Readers may recall that last year TDL Marine managing director Kelvin Travers drove a twin-outboard powered 12m version up to Noumea, quashing naysayer’s claims that the voyage couldn’t be done.
To date, most of the company’s boats have been powered by four-stroke outboards, but the latest incarnation – the 9.5m Silver Tiger Waka Rua – has been fitted with twin inboard diesels.
Dropping Volvo Penta D3-160’s into each hull has enabled the cockpit area to be extended, thereby creating a considerably larger fishing area for about the same overall length. In addition, these five-cylinder, 2.4-litre powerplants are light and compact and easily fit into the relatively narrow space.
The power-to-thrust equation is via Volvo duoprop stern legs which can be elevated above the water for easy inspection or removal of anything fouling the props. Sternlegs also allow the boat to be run up onto a beach safely, and the 800mm draught sees the cat venturing into areas off limits to most monohull launches.
Trade A Boat recently spent a day fishing on Waka Rua (purely to test the boat, of course). The boat was in final stages of handover to the new owner, with the usual post-delivery tweaking and tuning of engines and electronics taking place. Following completion of sea-trials, she will be based in Whitianga.
The cat’s been set up for serious game fishing – and that’s driven the switch to inboard engines. Because the cockpit now extends over the sternlegs, there are no protruding propellers to snag the line during those crucial seconds when the big one is up close and thrashing about.
A centre-mounted game-chair dominates the large, self-draining cockpit, although for our snapper fishing trip in the Hauraki Gulf this was replaced by a table fitted to the same pedestal mount.
The flybridge boasts a rocket launcher with six rod holders. This, plus eight other holders distributed around the gunwales, offers plenty of options for different fishing gear configurations. A clever feature is the live-bait tank built into the transom: it comes with a clear panel for monitoring the condition of the “livies”. A pump circulates water through the tank to keep them fresh.
One of our party managed to catch a squid on a sabiki, and it was fascinating to watch its behaviour through the “fish window”. A nice touch is the lid of the live-bait tank: it flips up to form a baitboard which can be stowed out of the way in seconds when the call comes to clear for action.
Each boat’s interior is customised to the purchaser’s requirements. Simple but elegant defines this boat’s main cabin layout. The catamaran configuration is ideal for a large double bed, with additional single berths placed in each hull. Weaver hatches provide plenty of fresh air and light. The single bathroom contains a toilet, shower and vanity with a hot/cold mixer.
In the saloon/galley, a dining table with padded seats accommodates four or more people, and a Serada SA3201 galley unit is hidden neatly under hinged glass covers. This boat’s owner opted for controls fitted only on the flybridge, so the main cabin is free of any encumbrances. A luxurious but durable marine carpet is fitted throughout, with teak fitted to the steps down to the cabins.
Back in the cockpit, a teak ladder leads to the flybridge where a central pod contains all the controls. The skipper’s seat is a comfortable, swivelling armchair, and it’s complemented by a padded bench seat around the front of the flydeck. The area is fully enclosed with large glass windows in the front and removable clears at the back. A wiper keeps the main window clear during rain.
Electronics are handled by Raymarine equipment. The C120 Multifunction Navigation unit, with its 12-inch colour LCD, is the primary display. Sounder, GPS, radar and chartplotter all display through this unit, and the software is simply and easy to use. A Raymarine Autohelm allows hand-free driving, and mood music is handled by a Fusion 5.1 sound system, playing through Fusion speakers in the flybridge and cabins.
On the foredeck a fully-automatic windlass makes dropping and raising the pick effortless. The owner of this boat will be using the foredeck to store a dingy, but once it’s launched, the foredeck’s a great area for sunbathing and relaxing. Foredeck access is via wide non-slip walkways along either side of the cabin.
The fact that some of the panels and covers had been removed due to the adjustments still being made facilitated investigation of build-quality, and overall workmanship is excellent.
Performance
And what of the ride? Wind and chop were a significant feature on our test day, but the cat handled it with ease. The narrow hulls sliced effortlessly through waves and swells, landing softly on the other side. No hint of frame-shuddering crashes – and there was no real requirement to ease up on the throttles: 25 – 30 knots remained the status quo.
TLD has carried out extensive fuel consumption tests on the diesel and outboard models. Says Travers: “The D3-160 diesel version burns two litres of diesel per nautical mile at 20 knots. The identical hull powered by twin Honda 150hp four-stroke petrol outboards has exactly the same rate of consumption of petrol.”
When you factor in the considerably lower cost of fitting the outboards, it would take almost 6000 hours of running before the diesels’ cost saving would cover their higher initial cost. In Australia, where diesel is not subsidized and costs almost the same as petrol, any saving from the diesels would take a lot longer.
Construction
A few days after the trip I visited TDL Marine’s Henderson workshop to explore the Tiger’s construction techniques. The design’s main, load-bearing parts are foam core, sandwiched between gaboon ply and fibreglassed both sides.
This makes overall construction very light but very strong, with the completed boat having a displacement of around 4000kg. Wooden bearers are spaced along the foam inserts, to ensure that the foam cannot split and undermine the strength of the panel.
The twin pontoons incorporate fully-sealed, watertight compartments every 600mm, ensuring that the boat could survive even severe damage without danger of sinking. All boats are built to New Zealand marine survey standard.
TDL Marine has three Silver Tigers under construction, with more on order, and Travers is investigating workshop flow to increase production rates and keep pace with demand.
And any time that happens, there’s little doubt that the design’s a winning formula.
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