Welcome Back ... to the Jet Age
Selecting the right boat is a process that takes time and careful thought. How do you want to use it? Fishing? Cruising? Watersports? That can become a long list. And there are some boats that’ll pass for multi-purpose. The fish-cruise pontoons come to mind.
But if you’re into performance boats, the field of candidate boats narrows and you’ll surely want to look into Scarab, a brand famous as a part of the go-fast boating world dating back to the offshore racing scene of the 1950s. In the 1980s, a Scarab 38 was featured in the popular television series, Miami Vice as the personal boat of the character Sonny Crocket. Later, Scarab was also featured as a rescue boat in the Baywatch series.
But those Scarabs weren’t jet boats. That propulsion system was introduced in the Scarab line in 2013. The boats have been redesigned with bold colors and an aggressive look as a nod to the competitive past, but laid out for “family purposes.” The jet propulsion is supplied by BRP Rotax 4-TEC 1503 systems ranging from 140-240 horsepower.
Water jet-powered boats have been around since the 1950s, but in the early ‘90s, sport jets powered their way into the market. Initially dismissed by “serious” boaters, they were considered toys; fast and agile perhaps, but a flash in the pan fad. And yes, they quickly peaked and quickly flamed out.
But the basic technology used in water-jet engines dates back well before the 1950s.
In fact, it can be traced to Greek mathematician, physicist, engineer, inventor and astronomer Archimedes of Syracuse who lived more than 200 years BC. His screw-pump design was initially used for transferring water from a low-lying body of water into irrigation ditches.
Today the design can be found in everything from windmill-powered drains in the Netherlands to combine harvesters in the Midwest. Oh, and in Scarab jet boats.
Ok, that might be a little bit of a stretch. There have been many refinements to the design since our hero lived and worked. If you’re a real stickler for giving credit where credit is due, you’ll need to issue some of it to Sir William Hamilton, who really does get credit for developing the modern jet boat.
Hamilton was a New Zealander and avid boater. He loved the fast, shallow rivers of his native land, but found that those shallows were a problem for deep draft, prop-driven boats. Of course, water jets had been around for many years (Remember Archimedes?), so Hamilton refined those designs. In 1960, he was able to become the first and only boater to navigate the Colorado River through the Grand Canyon. So those shallows prominent in parts of all the lakes of the Piedmont don’t seem quite so daunting now, do they?
Likewise undaunted, manufacturers began building larger, more powerful water jet engines, improving designs as they went. Today, when combined with personal watercraft, jet propulsion accounts for nearly 45 percent of the American powerboat market. The marine industry is set up for an unprecedented introduction of jet-powered boats that will shake up the market and, according to experts, will likely spur innovation to further advance the industry’s latest jet revolution.
Their allure remains the same as it always has been: thrilling acceleration, a more compact powertrain and the lack of a spinning propeller off the stern. In the fiberglass runabout category, these boats are sporty and aggressive, but also well suited for versatile family outings.
Several years ago, SeaDoo dealer Lake Norman Power Sports added FourWinns boats to their product line, then Scarab Jet Boats. It’s a natural fit, since SeaDoo builder Bombardier Recreational Products, also supplies the same Rotax technology in engines it builds for Scarab.
Differences between Sterndrive
and Jet Propulsion
Place a sterndrive boat and its jet-drive counterpart beside each other and the difference is glaring. A sterndrive engine, based on an automotive engineering, is significantly larger and weightier. The sterndrive’s drive shaft/propeller system is heavy, exits the hull and makes two turns before linking to the propeller. The jet boat’s drive shaft links directly to the impeller housed within an enclosed jet pump. This reduced profile alone gives these boats design freedom not available to sterndrive builders.
The jet engine offers amazing handling at high speeds – the directional nozzle offers quick, tight turns unknown to sterndrive boats while maintaining stability and control. Jet boats can also do well in low-speed maneuverability once you master their idiosyncrasies.
Sterndrives provide thrust in the same direction as the rudder, and propeller motion can be stopped in order to idle. However a jet engine is always pumping water, so neutral or reverse is achieved by a gate redirecting water flow in the desired direction. Although this will take some practice at first by someone used to conventional propellers, it won’t take long before this constant thrust can be used intuitively.
But you also have to consider the relative safety of having an enclosed impeller: Jet boats have no whirling blades or hardware that hangs beyond or below the hull. Their pump and nozzle configuration provides less draft, which reduces the likelihood of damage resulting from hitting underwater objects. Like rocks. Sir William Hamilton would be proud.
So as you’re making your list and thinking about what you want from a boat, give Scarab a look. See the boats up close at Lake Norman Power Sports and at the Mid-Atlantic Boat Show just around the corner in February.
On the left is an old drawing illustrating the movement of water using an Archimedian Screw, a hand-driven pump. Replace the poor soul turning that screw with a Rotax engine along with some spiffy boat design, and you get the fun lighting up the faces of these pretties aboard a Scarab 165.