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New Boat Engines for 2013
Mercury TDI SmartCraft
Who Wants It? Boaters seeking relief from ethanol worries associated with gasoline engines.
Importance? High efficiency, high performance and high torque in a small footprint.
Indmar Assault 345
Tow-sports enthusiasts keep throwing boatbuilders new challenges. First they wanted a ski boat with no wake. Then a wakeboard boat with lots of wake. Now they want to wakesurf, which requires the boat to list way over to one side while powering down the lake. Trouble is, the engine that powers tow boats was originally designed for a pickup truck, not an airplane. Tip it on its side, and the oil sloshes over in the sump, creating problems. So Indmar introduced its Assault 345, a 345 hp, 5.7-liter V-8 with an air-oil separator that prevents oil induction to the positive crankcase ventilation (PCV) system. The Assault 345 also has a generous seven-quart baffled oil pan to deliver adequate lubricant during high-G turns. It makes 370 pound-feet of torque for outstanding pulling power. The Indmar Assault 345 is offered by tow-boat builder Skier’s Choice in its Moomba and Supra brand boats.
The Yamaha SHO power train is new in the company’s SX/AR192 sport boats for 2013, but this jet-drive system has been used in its WaveRunner personal watercraft since the 2008 model year. In a 19-foot sport boat, this supercharged/intercooled, 210 hp, 1.8-liter four-cylinder is lightweight, compact and technically sophisticated when compared with available sterndrive power. The Yamaha engine and pump combined weigh 306 pounds. Consider that a small-block V-8 sterndrive like the new 225 hp Volvo Penta V8-225 weighs more than 1,000 pounds with an outdrive. That’s a big advantage for the Yamaha system in a lightweight sport boat, whether it’s on the water or being towed — it weighs less than 3,000 on its trailer. The compact size and low profile of this power train allow Yamaha to design a transom with a low center step-through, two-level lounge and swim platform that can’t be duplicated with a sterndrive.
Yamaha’s SHO comes equipped with a digital throttle that enables Cruise Assist, a system that allows the skipper to lock in any engine speed at the push of a button. Through a toggle switch on the helm, boat speed can then be adjusted up or down in increments of approximately 200 rpm to dial in the perfect speed for towing a wakeboarder or the kids on a tube. No Wake Mode can be set to a desired engine rpm in five increments from 1,100 to 2,100 rpm, holding a modest speed in no-wake zones with enough thrust to keep the rudderless boat on course. Set at about 1,800 rpm, it delivers good control for most docking situations and stays engaged as the lever is shifted from forward to reverse thrust. With a little practice you can execute low-speed maneuvers by just shifting and steering.