in (130 cm)
57 in (145 cm)
13.5 in (34 cm)
8 in (20 cm)
13 in (33 cm)
14.25 lb (6.4 kg)
Standard unleaded gasoline, 2-cycle oil, cable oil & 8 "AA"
radio box lid retainer
has been producing a long line of competitively priced boats for every
budget for quite some time. In this case the RIO 51Z is a ready-to-run
gas-powered deep-v boat. While that's not necessarily special, what
Aquacraft has done is special.
They've utilized the experience of a long time racing champion to
design the boat, installed a high quality Zenoah marine engine,
included high-performance GrimRacer hardware and use their Tactic
2.4GHz Spread Spectrum radio system. And they've done all this for less
money than their competitors.
There are a lot of well thought out details in this boat and is for the
intermediate to advance boating enthusiasts and racers. I like the way
it looks, and the simplicity in which it seems to have been designed. I
anticipate a strong value for the money with this boat, so let's take a
is going after all boating enthusiasts with the Rio 51Z, but the focus
is on racing in general; racing with your friends, family or even in
competition. GrimRacer explained to me that while boating is an
enjoyable hobby on its own, it really comes alive and can be addictive
when you race with your friends or even in competition. This is where
the Rio 51Z is looking to impress people; a ready to run, race ready
boat friendly enough for everyone, yet competitive out of the box.
Take a look at what they did.
business end of the boat shows how serious they are about how much fun
you'll have with the Rio 51Z. From the box to the water requires a few
and install the prop
batteries and check radio controls
the rudder is as simple as tightening two bolts, so let's look at the
prop since that is likely where most people will have questions.
Balancing a prop is critical to the performance of the boat and a step
that CANNOT be overlooked. A prop that is not balanced will create
significant vibration and premature wear on the components of the boat.
It will also diminish the boat's performance dramatically. Don't
overlook this step and take the time to do it right.
you are interested in getting into boats or already have a few, you
should take a look at the precision machined GrimRacer prop balancer by
Aquacraft Models. I've always used airplane prop balancers in the past
which work ok, but the GrimRacer balancer is specifically designed for
GrimRacer Precision Metal Prop Balancer
The GrimRacer Precision Metal Prop Balancer comes with a manual, so if
you're not feeling confident about balancing a prop have no worries.
I found the manual to be very descriptive in both text and pictures.
Getting a well balanced prop will be simple for anyone. Take a look
through the manual for instructions.
are 3 thumb level adjusters combined with a bubble level to ensure the
most accuracy when balancing a prop. There are also different size
balancing shafts to fit the prop securely. That is a well thought out
addition to this balancer as not all prop hubs are the same dimensions.
The balancing shafts also have a holder on the balancer itself so
losing them shouldn't be a problem.
This is a well thought out balancer that I have no doubt will last for
THE RIO 51Z
Thrust Angle Adjustment
a look at the business end of the boat and you'll find from the factory
it's ready to race. However, you can also tune the trim tabs and prop
thrust angle for peak performance. There are two 4mm hex bolts on the
side of the srut mounting brackets. You can adjust how the boat handles
and where the hull rides in the water by adjust the prop to the
positive or negative positions.
The positive position will lift more of the hull out of the water for
improved speed. However, it will also make the boat more difficult to
control and can even result in the boat lifting off the water
completely in rough water. The negative position will push the bow into
the water more. While this may be conducive to rough water conditions,
it can also cause the hull to plow through the water, reducing its
speed and increased it's chances of stuffing the boat under water. The
prop position is set to neutral from the factory and I found to provide
the best overall performance for everyday driving.
You can also adjust the trim plates in the same way, positive and
negative. If the trim plates are high (positive), the boat will have a
tendancy to go faster in the water but can have a tendency to porpoise
(bounce in the water). If set negative, the boat will be more stable,
yet slower in the water.
Adjusting both the prop position and trim plates can really dial in the
boat to that day's conditions and your driving style and preference.
That said, you don't have to touch a thing as the neutral position from
the factory will give the best overall performance. Adjusting can come
later after you've learned the boats characteristics and how you want
it to perform better.
has a purpose on this boat (aside from the mirrors) as you can see by
the air scoop. It's a scale, yet functional component of the hatch that
gets cool, fresh air to the engine.
The cowl locks combined with the dowel on the front of the hatch
provide secure but fast access to inside the hull.
Optional Quick Start
setup on the Rio 51Z was carefully thought out and simplified. The
radio box, fuel tank and engine layout provide easy access to
everything for balance as well as routine maintenance.
Aquacraft upped the anty with this boat by including a 2.1 hp, 26cc
Zenoah G260PUM. It's proven to be among the most reliable marine
engines and will provide years of reliable service when properly
They've also included a quick start method for ease of starting. While
you can still use the pull start, you don't have to if you have a
starter or wanted to purchase one. It's a simple addition, but one that
Cable Oil Reservoir
are two tanks on the Rio 51Z, one for fuel and one for cable oil.
Fastened with bungy cords make care and cleaning very simply. The fuel
needs to be mixed with oil and Zenoah recommends a 16:1 ratio.
The cable oil reservoir is used to keep the prop cable lubricated
during using GrimRacer Cable Oil.
The radio box is secured using a wire
retainer, of which I wasn't all that fond. While it does secure the
radio box lid well and definitely keeps out water, I didn't like that I
had to have a screwdriver to remove it and wonder how long it will last
before one of the plastic tabs breaks. I'm thankful it doesn't secure
with screws, but there are other ways it could be done that would be a
little more user friendly for the long term.
Inside the radio box, you'll find the battery holder, throttle and
steering servos as well as the rx for the Tactic 2.4 GHz transmitter.
As you can see, extra care was taken to enclose the rx in a balloon for
additional protection from moisture and water.
The throttle servo also has a kill switch, activated when you apply the
"brake" on the transmitter. Yes, I admit my panic triggered the
occassional "brake" reaction and I had to paddle out to retrieve the
boat a couple times. Having driven cars for years, applying the brakes
is a natural reaction for me when I have a wheel in my hands and I had
to on more than on occassion I had to remind myself boats don't have
So far the boat has exceeded my expectations, but I've yet to get it
out on the water so let's talk about that next.
what makes the Rio 51Z a boat I want to one and drive for the next
several years? Performance is where all the work shown above will come
into play. I'm anxious to see if all the things they did while
designing the boat actually work when the boat put into the water?
Afterall, nothing else matters if the boat doesn't perform so let's
take a look at my Rio 51z experience.
First of all, the Rio 51Z demands attention when you fire it up for the
first time. On a small lake such as this, the engine roars and echos
across the lake. Soon after firing it up, you'll see several people
peering out their windows to see what's going on. And if you really
want to turn heads, several gas powered boats racing always seems to
I found the engine a little tempermental at first, as it didn't want to
idle very well. A few adjustments to the throttle servo solved that
problem and had the boat running as expected. I took care to run
through a tank of fuel in 8 minute increments as instructed in the
manual. Break-in can be easily overlooked, but should always be done
with care. It's important for engine reliability and longevity.
There's a few things I'm interested in when it comes to driving
performance. The first thing is how quickly the boat gets on plane and
up to speed. Obviously, water conditions will play a factor here but
overall the boat feels light in the water out of the box. I found the
boat very responsive to throttle input and like how it darted forward
when giving the throttle a squeeze.
The throttle response makes cornering much easier to control. The Rio
51Z is smooth through the corners and is very easy to control with a
combination of steering and throttle. Guide the boat around a turn and
use the throttle to assist and you'll find the boat will do exactly
what you ask of it. It responsds very well to inputs throughout a turn.
In a straight line the boat holds its line very well and confidently
cuts through wake without a tendency to porpoise or chine walk. It
gives me confidence when driving that I can peg the throttle in light
wake and not worry about how the boat will respond. This is important
in racing as chine walk and porpoising equal slower lap times.
Rio 51Z is big. It's beautiful. It performs. It's not without it's
faults, but it is a great way to get into racing without the work
required in purchasing a hull and building one yourself. It's hard for
me to think someone would be disappointed with this boat for the price.
It is both for casual driving and racing use and is almost ready to run
out of the box.
I would recommend this boat to my friends (and have) and look forward
to years of fun from this boat.
The comments, observations and conclusions made in this review are solely with respect to the particular item the editor reviewed and may not apply generally to similar products by the manufacturer. We cannot be responsible for any manufacturer defects in workmanship or other deficiencies in products like the one featured in the review.