The next considerable decision is which kind of radio controlled boat hull to select. If your are planning a scale project, your option will apparently be determined by the full-size craft you would like to model. But sport, racing and sailing boat hull types demonstrate very special characteristics. In general, there are two hull classifications: monoplane and hydroplane.
MONOPLANES Monoplane hulls have one continuous surface in contact with the water. Monoplane hulls can be divided into two subcategories: deep-V’s and shallow-V’s.
Deep-V’s. As a rule monoplane hulls are deep-V’s. This typical design brings the keel to a sharp point well below the surface of the water. The underside of the boat is sloping upward steeply toward the hull’s sides, resulting in a radio controlled boat that knifes through the water with a comparatively large wetted surface area. This kind of hull is stable at every speeds and provides sharper steering reaction. The downside is that the additional hull surface that contacts the water causes drag that limits top speed. Still, with the correct power system and accurate fine-tuning, these radio controlled boats are quite fast especially for the beginner.
Shallow-V’s are the faster of the two monoplane types since they function with a smaller amount surface area in contact with the water. The shallower keel vee-angle produces a flatter bottom that causes less friction. The downside is that a lesser amount of contact with the water means a reduced amount of stability, so they are more difficult to control and demand more defined trimming. Shallow-v’s are very widespread for entry-level racing, this type of radio controlled boat or the so-called Crackerboxes being the most common.
HYDROPLANES Hydroplanes have more than 1 surface in contact with the water. They include tunnel hulls, catamarans, outriggers and stepped hydros.
Tunnelhulls are generally often related with full-size racing boats. They get their name from the raised center section of the hull. Two outer sections or sponsons sit in the water with a tunnel between them. As the boat gains speed, air builds up in this tunnel and raises the boat higher out of the water. This reduces the surface area that contacts the water. This means less drag and higher speeds, while the relatively wide spacing of the sponsons maintains stability. This model provides a good balance of speed and handling for newbees.
Catamarans (cats) operate on the same principle as tunnelhulls and fluctuate only in contour . They have more steeply angled sponsons much like deep-v’s monos with a tunnel along the center. A catamarns tunnel tends to be taller and narrower than a tunnelhull’s, so it takes longer to preserve stability. These also, are a good beginner design.
Outriggers are at the uppermost of the performance ladder; their sponsons and main hull are separate pieces. This improves the airflow at high speeds, so outriggers are the fastest radio controlled boats; some even run at more than 90mph! The obstacle is that they are intended to work best at full throttle. At slow speeds, they sit too low in the water and do not handle well. Also, they are the least forgiving when it comes to setting the trim.
Stepped hydroplane hulls contain notches perpendicular to the centerline that separate the wetted surface into 2 or more sections. These notches pick up the radio controlled boat up on step faster, and that improves performance. At speed, these notches decrease the wetted area, reducing drag. This hull type includes a varied group, from simple deep-vees with little steps in the hull, to 3-point hydro racers such as the full-size Miss Budweiser turbine-powered, unlimited hydroplane. At full speed, three-point hydros ride on 2 tiny areas of the forward sponsons and the centrally located propeller at the rear.
Any way you look at it radio controlled boats are a terrific way to spend a sunny afternoon. Take the time to enjoy the sport and spend time with your kids and friends.
