How To Get Into Hobby RC: Boats Boats Boats!

By Terry Dunn

Testing an entry-level RC Boat and a step-up speedboat upgrade.

Although I’ve owned a few RC boats over the years, they are my least familiar RC vehicle by far. In many regards, writing this guide has been an example of “learning by teaching”. Looking back to the first article of this series, you may recall that I recommended the AquaCraft Reef Racer 2 for anyone just starting out in RC power boats. I own a Reef Racer myself--three of them actually. They’re a little addictive. I recently stepped up to a brushless-powered speedboat as well. And both boat types have been unexpectedly fun in unique ways. Let’s take a look.

The AquaCraft Reef Racer 2 is an ideal boat for beginners. It is not very fast, but it is extremely nimble.

Inside the Reef Racer 2

The Reef Racer comes as a complete package with the boat, a pistol-grip radio, battery, and charger. It is available in six different colors. Each boat color also represents a different radio frequency, so you can operate different color boats simultaneously. The Reef Racer also comes completely assembled as well. All that you have to is charge the battery and head to the nearest lake.

The drive system for the boat is very simple. An electric motor near the front of the boat is connected to a shaft that runs towards the back of the boat and out through the bottom of the hull. This shaft is contained within a tube that is filled with grease (called a stuffing tube). The grease in the tube provides lubrication and also prevents water from entering the hull. At the end of the shaft is the propeller.

With the top shell and watertight covers removed, you can see the layout of the components within the Reef Racer’s hull. Note the on/off switch that I felt was unnecessary and removed.

To keep the motor running relatively cool, it is wrapped with a coil of aluminum tubing. This coil is connected with flexible tubing to a water pickup in the bottom of the hull. As the boat moves forward, water is forced into the pick-up and through the coil to provide conductive cooling of the motor. Once through the coil, the water is dumped overboard.

Steering for the Reef Racer is accomplished via a completely submerged rudder placed just behind the propeller. A shaft on the rudder protrudes into the hull where a small servo actuates it in either direction. It is a very simple and effective system.

This mini servo operates the rudder through a very simple mechanical system. It has plenty of control authority to make the boat turn on a dime. The Receiver/ESC unit is the black box beside the servo.

The radio receiver and electronic speed control (ESC) for the motor are combined in a single waterproof housing. Emerging from this housing are the radio antenna, leads to connect the rudder servo, the battery wires, and a power switch. This all works well as-is, but I made a few modifications that I thought would improved the boat’s longevity. I will explain my tweaks later in this guide.

A NiMH battery and peak charger are included with the Reef Racer 2. This view shows the stock power connectors, which I later changed for improved longevity.
Peak chargers automatically shut off when the battery is fully charged, so you do not have to worry about over/undercharging as you do with a timed charger.

The included battery is a 6-cell pack of 2/3A-sized NiMH cells providing a nominal voltage of 7.2v (1.2v/cell) and 1100mAh capacity. The website for the Reef Racer shows that it includes a rudimentary timed charger. I was pleasantly surprised to see that it now includes a peak charger instead. Peak chargers automatically shut off when the battery is fully charged, so you do not have to worry about over/undercharging as you do with a timed charger. I measured the charge rate to be 1.5 amps, so a fully depleted battery will take about 45 minutes to recharge. I used the charger a few times to make sure that it works okay--it does. Subsequent charges of the Reef Racer’s battery have been on my dedicated workshop charger (my beloved Hitec X4-eighty).

A really neat thing about the Reef Racer’s design is that it has a top shell (the part that comes in different colors) that attaches to the hull with Velcro. If the boat ever capsizes, the buoyancy of the shell makes it flip upright again. Most boats would remain inverted until you waded, swam, or boated out to retrieve it. The Reef Racer can simply be driven away once it self-corrects.

The AquaCraft Reef Racer 2 is an ideal boat for beginners. It is not very fast, but it is extremely nimble.

Things I Changed

Right out of the box, the Reef Racer is a solid boat that I think most beginners (and others) will be happy with. There is absolutely nothing that must be changed to make the boat fun. It is a well-built turnkey package. That being said, I noticed a few things that could become potential trouble areas down the road that I alleviated up front. If you are comfortable with a soldering iron, you may want to make the same changes as well.

I am fundamentally opposed to mechanical on/off switches on all of my RC vehicles. They are just too unreliable.

I am fundamentally opposed to mechanical on/off switches on all of my RC vehicles. They are just too unreliable. When the switch goes south, so does your control of the vehicle. Unless having a switch is absolutely necessary, I remove them from the system. I think the Reef Racer is one of those cases where the switch is superfluous. I can’t think of any scenario where I would want to have the battery plugged in and the switch off. So why have a switch at all?

To bypass the switch, I cut the wires leading to it, leaving about 1” emerging from the receiver/ESC housing. I then stripped enough of the remaining wires to twist them together and secure the joint with solder. I then weatherproofed the solder joint by covering it with Goop adhesive. I used a piece of tape to cover the open area where the switch was mounted. Now the onboard radio equipment immediately turns on as soon as I plug in the battery. While 90% of the RC equipment I’ve dealt with works this way, I have seen examples where I had to leave the switch wires disjoined to arm the device. In that case, you can just cut and insulate the wires.

The battery connectors included with the boat are Molex connectors, commonly called “Tamiya” connectors after the RC brand that made them popular in the 1980’s. Tamiya connectors work well enough at first, but the contacts soon get sloppy and dirty. This condition causes high electrical resistance which wastes battery power and reduces overall performance. I switched all of my power connectors to Deans Ultra Plugs long ago (there are several good alternatives to choose from) and followed suit with the Reef Racer. High performance connectors such as Ultra Plugs will give consistent, low-resistance performance over many years.

As with most RC vehicles, you probably want more than one battery so that you can get in several runs before having to reach for the charger. As I write this, spare batteries are selling for about $30 each. For those of you new to the RC scene, this is probably the best option. If you already have a selection of batteries, as I do, there are a few alternatives. I have successfully used 2-cell 1100mAh A123 batteries (smaller versions of the 2300mAh A123 batteries that I prefer to run in my RC cars), as well as 2-cell 1100mAh LiPo batteries in the Reef Racer. Even though the A123 and LiPo batteries are a little lighter than the stock NiMH battery, the voltage and capacity values are very similar and I didn’t notice any appreciable differences in speed or endurance.

The Reef Racer’s included charger is only intended for NiMH cells, so don’t even consider it for anything else. Also, the boat’s ESC does not have any sort of voltage cut-off feature to prevent over-discharge of the battery. This is a non-issue for NiMH and A123 batteries because those chemistries tend to be quite tolerant of such abuses. LiPo batteries are another issue entirely. If you decide to use a LiPo in the Reef Racer, be very conservative with your run times to prevent draining the battery too much and damaging it…probably permanently. If you are not already well versed on the care and feeding of LiPo cells, just ignore this option with the Reef Racer.

Driving the Reef Racer 2

It is hard to describe the performance of the Reef Racer. Perhaps “perky” is appropriate. It isn’t what I would call fast, but it is definitely several notches above toy-grade boats. While its top speed isn’t going to set the lake on fire, it reaches that speed quickly. It’s like a car stuck in low gear, ok…maybe mid-gear. This has several benefits for beginners. First of all, rookie boaters are not likely to lose control of it and plow into the lily pads (my 11 year-old son mastered it very quickly). Secondly, it doesn’t bog down. When you give it power, the Reef Racer is instantly “on plane” and in cruise mode. Lastly, the Reef Racer’s moderate speeds allow for long run times. I routinely get 10 minutes on each charge and I’ve never run a battery completely dry.

The Reef Racer includes a 27MHz pistol grip radio. Six different frequencies are available so you can run multiple boats at the same time without signal interference.

The Reef Racer is exceptionally nimble. When you turn the control wheel, it will whip around in a heartbeat. Again thanks to its “low gearing” of the propulsion system, it doesn’t bog down in these tight turns. It just goes. I’m sure that with a little practice you could operate one of these in a moderately sized pool and never hit the edge. I take my Reef Racers to the small ponds found at many of my local parks and they are way bigger than I ever need.

While the Reef Racer is fun to drive around, carving solo figure-eights in the water, I have the most fun when my son and I drive our Reef Racers together. We drag race, play follow-the leader and try to one-up each other with precision driving moves. While we don’t intentionally crash into each other, we don’t put much effort into avoiding contact either. Most times, we just laugh it off and keep driving. If a crash looks particularly rough, we’ll bring the boats in for a quick shoreline inspection. You don’t want a busted propeller to cause your boat to vibrate itself to pieces. The worst damage that we have caused so far was a small puncture hole in one of the colored shells. I patched it with clear packing tape and it’s still going strong.

The more I operate my Reef Racers, the more convinced I am that it is indeed an ideal starter boat. It is dead simple, which lets rookies get a feel for the basic mechanics RC boats with a reliable system. At one point, I thought that the Reef Racer would be a good platform for high-speed hop-ups. After investing a little time and money installing a brushless motor and ESC, my boat was indeed faster. However, I thought that it somehow lost the charm it had when stock. I converted it back. I later satisfied my speed jones with a boat designed specifically for that purpose.

Going Fast with the Minimono

The Minimono is another small electric boat in the AquaCraft lineup. It is actually very similar in size to the Reef Racer 2. Even the propulsion system looks very similar to that of the Reef Racer. There are subtle differences, however, that make the Minimono the faster boat…much faster. Perhaps most significant is that it includes a brushless motor which is intended to use a 3-cell LiPo battery (which is not included).

Although similar in size and layout to the Reef Racer 2, the AquaCraft Minimono is a very different boat. Its brushless motor and 3-cell LiPo battery push it to much faster speeds.

The Minimono includes a 2.4GHz pistol grip radio. In this case, the receiver and ESC are separate components. The water cooling system is attached to the ESC as well as the motor. In addition to the rudder, there are aluminum turn fins attached to the transom (the back wall of the hull). When the boat leans into a turn, these fins dig in to the water to keep it on track.

The Minimono is at least twice as fast as the Reef Racer.

Whatever similarities there may be between the Minimono and Reef Racer, they disappear when you squeeze the trigger. The Minimono is at least twice as fast as the Reef Racer. When you punch the throttle, the Minimono wallows a little and lifts the bow. As the bow comes back down, the prop picks up RPMs and the boat shoots forward like a rocket. At top speed, the Minimono dances across the lake with just the very back end of the hull touching the water.

Under the hood of the Minimono we can see the brushless motor (far left) and the 3-cell LiPo battery (center) that help to give it such crazy speed.

I’ve been very surprised by how quickly the Minimono can carve a turn. At first, I was taking it easy and slowing down for every turn. I eventually figured out that I could really scream through the turns without flipping the boat over, or even skidding. I can’t even imagine how many lateral Gs it’s pulling though some of those turns.

If driving the Reef Racer is a carefree frolic, driving the Minimono is an exhilarating thrill. I have to devote intense concentration just to keep up with the speed of the boat, not to mention maintaining awareness of the objects I want to avoid hitting. I can only equate it to the experience of flying some of my high-performance RC airplanes. It’s a lot of fun, but I need a breather when it’s over.

Other Boating Options

As small electric ships, the Reef Racer and Minimono represent the current mainstream of RC boating. There are definitely many other options including sailboats, airboats, hovercraft, wet-fuel powered speedboats, submarines, and even warships that try to sink each other. For now, I’m really enjoying these little electric ships. In an upcoming guide, we will look at an off-the shelf airboat as well as a simple do-it-yourself version. The next installment of this series will cover RC airplanes!