Sport C Racing Driving
Driving and Setup Basics
Driving a Sport C is done with your thumb! On most courses the foot throttle stays pegged. The power trim buttons are mounted on the steering wheel, have an incredible amount of control over the boat. Trim down to enter the corners and stick the sponson to the water. Trim up on the straights to climb up on the air and get the boat free and fast. While running the straights you may need to bump the trim down to keep from getting too much air under the boat though. It is very rare but Sport C's can blow over. If everything gets quiet while running fast, the right response is to trim down. This will drop the nose and not scoop as much air under the boat. Just letting off on the throttle may have a bad effect. The boat will drop down, but instead of collecting less air, it may jump onto the air already under the boat, compressing it like jumping on a trampoline, throwing you up and possibly blowing over.
Race boats have a handful of instruments on the dash. The most vital part of driving is not only triming, but having a trim indicator. Typically this is a throttle type push pull cable that extends and retracts across the top of the dash. As a driver finds the sweet trim spots for the straights, cornering, and getting on plane, they'll mark the indicator gauge accordingly. Another common gauge is a tach. Not only will a tach tell you what the motor is revving up to with a given prop, but on the straights and cornering it can help you keep the motor wound out, but also not screaming away without grabbing the water (over trimmed). Some drivers will also add a GPS speedo of one form or another. This can be anything from a GPS driven analogue display, to a handheld velcroed to the dash. The final common instrument is a kitchen timer. There are 2 kinds of starts, LeMans (dock or beach starts), and clock starts. A typical clock start gives 3 minutes of warmup before the running beginning of the race. Knowing when the clock will hit zero helps a driver get to the start line at the right time. Too early and you jump the gun, earning a DQ. Too late and you'll spend the whole heat trying to catch up to everyone who started just right.
Prop height is also a very important part of racing these boats. Every boat and every prop likes a different height. It may only be a change of 1/16" that makes all the difference. Too high and the prop won't bite the water, or you'll spinout on corners. Excessive height can even result in walking sideways on a straightaway. Too low, and the motor will be bogged down, never reaching ideal HP producing RPM and being very sluggish out of the corners. Different courses, short and tight verse long and wide, also make a difference on prop selection and height. That's where testing becomes very important.
Both at races and during independent test sessions a log book should always be kept. That's how you keep track of what changes to weight distribution, prop height, motor tuning, and the like increase of reduce speed. It's also how you know what prop and at what height you need to run for any particular course. Some races require high cornering forces, other's all out speed is the goal. Elevation also affects oxygen content, and therefore HP, and that drives what prop and heigh you want to run. All of this comes from that log book you've been writing in.
Just because some drivers have a well prepared boat and extensive log doesn't mean they're unbeatable. Most of it comes down to driving skill. And even a fast boat can ding a prop and have to start their testing process all over again with a new one (every prop drives different even if it looks exactly the same). Maybe they wear out a motor and it's power curve isn't quite the same after the rebuild. Other times people make changes to hull shapes and running surfaces. The change could produce more speed, but that doesn't mean it will corner the same.
