I recently got to test-drive an Axius-equipped
2008 Sea Ray 330 Sundancer, and all I can say is that
it was incredible! I was blown away by how nicely everything
worked, and am still grinning from ear to ear as I
write this! I can report quite honestly, as I am not
relying on Sea Ray advertising to pay for this site.
For starters, the test boat was a
2008 Sea Ray 330 Sundancer that was slipped on the
A-Ramp at Captain's Quarters. The boat was equipped
with twin 496 Magnum® SeaCores with Bravo III sterndrives
and Digital Throttle/Shift (DTS). Each engine was rated
at 375 hp., and the Axius system increased the MSRP
by a little over ten percent.
If you haven't heard much about the
Axius system yet, I'll explain in layman's terms how
it works. I should note that there are many technical
details associated with the system, and I'll do my
best to recall how it worked. At its simplest level,
you get a side-mounted joystick that sits to your right
at the helm. You can move it forward and backward or
side to side to control the movement of the boat. The
top of the joystick rotates, enabling you to pirouette
the boat with a twist.
To understand how the system works,
it helps to understand the components. In a conventional
twin sterndrive, each lever has a throttle cable connected
to each engine and a shifter attached to each transmission.
The steering wheel is mechanically linked to both drive
units, so they always move together.
Above, the DTS shifter
and Jim Tingle from Sea Ray of Louisville
Adding DTS to the system does several
things for you. The shifting is smoother, as it is
computer controlled as you move out of the neutral
detent. The throttle acts as a rheostat, sending an
electronic signal to the engine for servo-controlled
throttle control. This makes for a much smoother feel
at the helm, as there is no cable friction or slop.
There is a "Throttle Only" button to control
the throttle without shifting, and a "Sync" button
that will synchronize the engines at cruise. Another
button on the DTS quadrant allows you to operate both
engines with a single lever, as indicated by "1
Lever." There is a "Transfer" option
that is not used on this particular boat--you would
use this feature if you had another DTS controller
at a different location, such as a wing bridge or the
stern of a larger vessel.
Using the joystick centers the steering
and activates the Axius system for docking. Selecting
the "Dock" button, as I understand it, reduces
the sensitivity on the joystick control. Unlike a conventional
twin, where the sterndrives are linked together, the
computerized steering has the capability of steering
the Bravo III drive units independently. The drives
can move outboard as much as 30 degrees and inboard
as much as 15 degrees.
It is pretty easy to visualize how
the computer uses joystick inputs to go forward and
backward. If you give a slight forward pressure on
the joystick, both drives nudge into gear at idle.
As you move toward full stick deflection, you command
up to 1500 RPMs on each engine. Reverse works the same.
Pirouetting the boat is very straightforward. A slight
twist of the joystick results in the drives shifting,
and a further twist causes the boat to rotate faster.
Releasing the joystick stops the input, and the rotation
stops as the rotational inertia winds down.
Moving the boat directly to the port
or starboard is something that you just can't conventionally
do with a pair of sterndrives tied together. Under
computer controll, it was easy and brainless! Take
a look at this rough diagram to help visualize how
To go to port, all the driver has
to do is nudge the joystick to the left. To move faster,
a little more pressure to the stick is all that is
required. The computer shifts one drive into forward
and pivots a sterndrive. The other engine goes into
reverse, with its drive pivoted the opposite direction.
A force diagram from high-school physics shows that
the forward and rearward vectors cancel each other
out, but both side components are added to give the
boat its sideways movement. The beauty of the system
is that all the shifting, steering, and application
of power is controlled by the joystick.
This all makes for good theory, but
how well does it actually work? On the day of my test,
there were two drivers new to the system. The river
was at 17 feet, so the test was limited to the slow-speed
handling. The first driver, we'll call him "the
other skipper" to save ridicule, was a very experienced
boater with twenty years of handling twins. By comparison,
I've been around boats for a while, too, but have also
grown up with video games, aircraft simulators, and
remote control helicopters. The experience with video
games and RC helicopters gave me a slight advantage
in that I am used to finessing electronic controllers
to achieve a desired result. Jim Tingle from Sea Ray
of Louisville was there to supervise the demo.
For starters, both "the other
skipper" and I instinctively used the shifters
rather than the joystick to make our first moves at
the helm. Was this wrong? We felt that we had more
control using what was familiar, but wondered if a
new driver would just use the joystick. Both of us
even used the shifters for our first ninety degree
turn. The other skipper commented that the boat seemed
to "leap" when the joystick was moved, and
that it could be smoother. He was very smooth using
the DTS, but found that twenty years of driving boats
made it a little difficult to quickly adapt to the
joystick. He commented that the system seemed to do
an excessive amount of shifting. Having said all that,
he did a fine job handling and maneuvering the boat,
both conventionally and with the joystick.
On the other hand, I found the joystick
to be very intuitive. While I've been around twins
for a while, I found that less experience with boats
and more experience with games and RCs helped me to
embrace the new technology without interference. I
found that a small pressure on the stick would cause
the drives to shift out of neutral, and an increasing
pressure would make for an increasing application of
power to make the boat more responsive. We had an occasional
crosswind, which sometimes required more than just
a slight pressure on the joystick to control the boat.
I found that using lots of finesse was the key to minimizing
the shifting and keeping the movements smooth. Fortunately,
the Bravo III units shift rather smoothly, so it seemed
that you could hear them go into gear almost more than
you could feel them using slight pressures. A larger,
more sudden input would definitely cause the boat to
jump, which I accidentally induced more than once.
I used a Monticello houseboat slipped
at the end of the ramp as a reference, and maneuvered
the Sundancer around the houseboat, moving forward,
moving backward, sliding sideways, and pirouetting
just to see what the system would do. None of the movements
seemed too jerky, and after just a few minutes, I felt
comfortably in control while handling a boat in close
quarters that I had never even seen before.
The Mercruiser Zeus and Volvo IPS
systems, which have been under development for years,
take advantage of pod drives to accomplish the same
thing as the Axius system. The advantage of the Axius
system is that it can be fitted to sterndrives already
Overall, I think these
types of systems will revolutionize the way recreational
boaters dock their boats in tight spaces. Will this
create a new breed of boaters who are crippled by their
reliance on technology? Like with other technologies,
I suspect that these systems will only expand the capabilities
of new boaters. My wife, who doesn't like docking our
convertible, for example, would be comfortable docking
this Sundancer after only a few minutes of training.
Having see the Axius system in action, I am forever
ruined. I will certainly wish I had it the next time
I return to my lay-along slip and have to spring in
to counter a crosswind.
Until next time, thank
you for reading! I would like to especially thank Jim
Tingle and Sea Ray of Louisville for providing the
opportunity to tryout the new Sundancer.
Founder, Port KY
Eric grew up around boats, trading summers on board his parents' Sea Rays for many man-hours of swabbing the decks. He grew up by the little town of Sewickley, Pennsylvania, overlooking the the Dashields Locks and Dam. He has traveled the Great Lakes, Lake Huron's North Channel, Gulf of Mexico and several rivers to include the Ohio, Allegheny, Monongahela, Kanawha, Mohawk (Erie Canal), Tennessee, Tombigbee, Black Warrior and Mobile Rivers.
As a commercial pilot, Eric flies jets and is a flight instructor. He has owned recreational boats ranging from PWCs to most recently, a flybridge convertible that he keeps in a Louisville marina (MM 590). You can also find him with his family on the "Escape Pod," an 18' fishing boat. His most memorable journey was aboard the J. S. Lewis, a 155' towboat in service since 1931.
Eric is a USCG Licensed Master with a Commerical Tow Assistance rating, and is a member of the Sons and Daughters of Pioneer Riverman and the Louisville Sail and Power Squadron. After moving to Louisville, he conceived the idea for Louisville's Port KY website while searching for information to help him become a safer and more knowledgable local boater. He has worked hard over the years to educate other boaters by promoting safety classes through Port KY and by hosting captain's classes and related events.