See full version: The great shift to outboards
Another sign that the power levels are increasing is that in 2008 the average horsepower in the United States for all outboards was 80. In 2017 the average is 105, and Caruana says that number is growing. Evinrude has revived interest in 2-stroke outboards with its E-TEC G2 series and Suzuki recently released its largest outboard to date, a 350-hp V6 with counter-rotating propellers.
“People are no longer worried about taking a single outboard offshore or out for a day on the lake,” says Meeler. Regal offers two models with a single outboard and three with twin outboards. Even legendary offshore powerboat manufacturer Cigarette Racing Team is selling more outboard-powered center consoles than traditional sterndrive go-fast-style boats. here
Five years ago if the boat brands Tiara, Cobalt, MJM, Formula and Regal were mentioned in the same sentence it would have been easy to assume the conversation was headed toward a discussion of luxury boats powered by inboards or sterndrives. Today each of these companies has embraced a trend that has taken over the recreational boating industry — dayboats with outboard power.
“If people are using their boats for dayboating, they want to get places fast,” says Glenn. “We’re trying to feed the customer who wants a little more pizazz.” here
Malibu CEO Jack Springer has called the outboard market the industry’s largest-growing segment. “We see significant opportunity to expand the brand’s reach,” he explains. “The outboard segment represents a big white-space area.” more
One of the big reasons Malibu Boats executives gave for the recent purchase of Cobalt Boats is to gain a better presence in the outboard-powered boat market. Long known for its diesel- and gasoline powered sterndrives, inboards and pods, Volvo Penta just bought high-performance outboard manufacturer Seven Marine, which builds 557-hp and 627-hp outboards based on a General Motors LS V-8 block. Heck, there are Ranger Tugs running around with an outboard clamped to the stern.
Dual Propellers should ALWAYS turn in opposite directions.
for cats setup for oval props spinning out help with cornering, really suck the rear end down. for SAW boats spinning in is the way to go low speed handling suffers though. here
Does it matter what direction the 2 props turn on a dual-motor/prop catamaran? Should they turn opposite ways? Which directions are best?
In contrast to the above, aircraft power generators in almost all aircraft today are effectively 2:1 oversized. For example, in the case of a generator designed to provide 270 V d.c. at 50% per unit (p.u.) speed, it ‘wants’ to produce 540 V at 1.0p.u. speed, but it is harnessed by the voltage regulator to 270 V. Also, when the 270 V d.c. is developed by rectifying the a.c. generator output by a three-phase full-wave silicon controlled rectifier (s.c.r.) bridge rectifier, only a small part of each (rectified) sine wave is used to produce the 270 V d.c; as shown in the lower half of Figure 47.16 . There is the irony also that the bridge-rectifier/filtration components are only efficient on the ground, at 0.5 p.u. engine speed! [links]
– Larger space requirements inside hull.
Rotational speed varies with power absorbed
Due to the pressure drop in the nozzle, cavitation occurs earlier. more
Can accommodate multiple operating conditions more
– Higher costs for propeller. more
Every once in a while we run across a boat running a counter rotating set up without the owner realizing it. All theories aside, it may not make any difference. Depends on balance, hull design etc. Should be interesting, let us know. [links]
Re: Direction of propeller rotation - LH or RH pitch
Re: Direction of propeller rotation - LH or RH pitch
Assuming standard boat construction prop rotation should not affect handling
listing etc. Many boats are setup for standard rotation RH. So LH rotation might affect the handling adversly on such a boat.If a boat was setup balanced Then changing rotation would simply reverse the torque affects of the prop. more
Re: Direction of propeller rotation - LH or RH pitch more
Re: Direction of propeller rotation - LH or RH pitch more