RC Boats

RC boat hulls, from the pool toy to the sailboat:

the shape under the water says more than the speed on the box. Toy boats are small brushed-motor hulls for a pool or a calm pond, and when one breaks it is finished. Hobby-grade boats split by hull. A deep-vee monohull such as a Traxxas Spartan or a Pro Boat Sonicwake cuts through rough water and, on most recent models, rights itself after a flip. Catamarans like the Pro Boat Blackjack, and hydroplanes, ride on a cushion of air and go faster, but only on flat water. Sailboats such as the Joysway DF65 are slow and quiet, and sail for hours on a small battery that only works the rudder and sail servos. Most of the electronics overlap with RC cars: the same LiPo packs, connectors and pistol-grip radios. The speed controller is the exception. A boat’s ESC is cooled by lake water running through it, and a car ESC fitted in its place overheats inside a closed hull with nothing to carry the heat away. Foam floatplanes that take off from the same water belong with RC airplanes.

Deep-vee or catamaran when the Xocomil comes up:

off Panajachel and the other towns on Lake Atitlán, the afternoon wind starts around one or two o’clock and by four it raises real waves. A catamaran or hydroplane in that chop keeps leaving the water, and every time the propeller comes out and bites again, the flex shaft takes the shock. A self-righting deep-vee rides it and flips back upright when a wave rolls it. If you run on a big lake, buy the vee. If your water is a farm pond or a sheltered lagoon, the cat is the faster boat. Either way, run in the morning, and keep a kayak to hand for a boat that dies far out rather than swimming after it.

Inside the hatch of a used RC boat:

take the hatch off before anything else. White or green crust on the connectors means the seal leaked or the boat sank, and a sunk boat is an electronics question however clean the hull looks. Pull the flex shaft out of its tube: it should come out greased and straight, not dry, rusty or kinked. Check the prop for chips, and the bow and keel for cracks from launching. Ask where it ran. On Lake Amatitlán, where the water hyacinth has to be pulled out constantly, weed wraps the prop and blocks the small pickup on the rudder that feeds cooling water to the motor and ESC. A boat run on with a blocked pickup may have a heat-stained motor can or an ESC that cuts out when hot. Moving in the water, the cooling outlet should push out a steady stream. A brushless self-righting deep-vee costs about ten times what a pool toy does, and most of that money sits in the motor, the ESC and the radio rather than the hull. A cracked hull or a bent prop is a cheap fix; a speed controller that has had water in it is not, and the price should drop by the whole cost of replacing it.

Listing a boat with the hatch off and the shaft out:

those two photos answer what buyers worry about most, so add the hull, prop and rudder from below. Give the make and model, hull length and type, brushed or brushless, the battery it takes and its connector, whether it rights itself, and what goes with it: radio, packs, charger, stand, spare prop. Say plainly whether it has sunk or been repaired, and which water it has run on. A brushless boat should not be run hard out of the water, so suggest meeting at a lake or pond in the morning with a charged pack, and let the buyer see the cooling stream before taking the radio.