HIGH PERFORMANCE BOATING AND YOU
Table of Contents
About This document..................................... (2)
Introduction to High Performance Boating...... (3)
Steering Forces......................................... ....(4)
The Motor.............. ..................................... (5)
Steering Systems ..... .................................... (8)
Propellers . . . . . . . . . . . . . . . ..................... . (9)
The Boat........... ..........................................(11)
Boat Equipment ........................................... (12)
This document contains certain information related to the personal safety of the operator, the passengers, and bystanders. Ignoring these safety issues will most likely cause injury. This document is an aid to understanding the operation of a high speed boat. It is not the only document about the subject that you should read before jumping behind the wheel of a high speed boat.
The continuing accuracy of this document cannot be guaranteed. All photographs and illustrations used in this document may not depict actual models or equipment and are intended as representative views for reference only.
Certain features or systems discussed in this document might not be found on all models.
(2) About This document
This document will familiarize you with preparing and operating a high performance boat. A high performance boat requires top quality equipment in both design and manufacture. You should seek the help of an experienced high performance boater or expert in the field of racing when choosing accessory equipment for your boat and motor. Your local dealer may be knowledgeable in helping you with these choices or may be able to recommend an expert.
When your boat/motor/propeller combination has been fully assembled, have that same expert check out the installation of all equipment, its proper function and test it on the water. A person who has not been properly trained in the operation of a high performance boat should never attempt to drive such a boat at high speed. Never allow passengers or friends to drive your high performance boat unless they are experienced high performance boat drivers. Loss of control at high speed can occur suddenly and can result in persons being thrown from the boat. Accidents associated with high speed ejection can be serious, but the chances of injury can be substantially reduced by using the proper safety equipment.
(3) Introduction to High Performance Boating
The performance limits of a high performance boat should be approached gradually. Even if you have experience in another boat, this one will probably react differently and you will have to adapt your skills to this new boat/motor combination. Your first few hours of use should be at part throttle and without passengers in the boat. This is the time when you should learn the effects of changes in trim, throttle position and steering.
What Can Happen to a Boat at High Speed's
As any performance boat approaches its top speed, only a very small part of the boat bottom (called the "pad") is still in the water. Because of this, the driver must perform a very delicate "balancing act" to keep the boat under control. This task is easier in some boats than others depending mostly on the shape of the hull. Some of the forces which you will be balancing include:
* Wind forces on the front or side of the boat
* Buoyant forces pushing up on the bottom of the boat
* Drag forces on the bottom of the boat and against the motor's lower unit, propeller, and trim tab
* Thrust forces from the propeller
* Twisting forces caused mostly by the torque of the propeller in the water
* Proper motor trim angle
* Boat loading to keep an even keel
Because the relationship of all these forces is very complicated, it is important that you gain experience slowly. This means starting at slower speeds and gradually increasing boat speed while under the guidance of an expert. Instability, which happens whenever the many forces become unbalanced, will usually send little signals to the experienced driver. Because of this experience he can slow the boat, trim the motor slightly, or give the steering wheel a nudge which will again put the forces in balance. As speeds increase, the little signals of something about to go wrong will give you less and less time to make the corrective adjustment to prevent more serious instability from happening. It would be unwise for any high performance boater to go blasting off at high speed before he can recognize these signals and know instinctively what to do about them.
Before Leaving the Pier
Remove any loose equipment and put it ashore. If you need it on board, make sure it is securely tied down.
Make sure all hardware used to attach the motor to the boat is in place and tight. Do the same for all the hardware in the steering system. This is very important.
Check the operation of the emergency ignition shut-off switch. Start the motor, pull the lanyard and see that the motor stops. Make sure the lanyard is securely fastened to your life jacket.
On the Water
Before taking a new rig to wide open throttle, operate it at slower speeds. This is the time to learn how the boat reacts to the various inputs - both operator and naturally caused.
With the boat running at 30 to 40 MPH, operate the trim switch. Note how the boat reacts when you have trimmed to bow U P and bow DOWN - particularly in turns. Reset the trim for the flattest ride, circle around and cross your wake. While holding it in a turn, observe your boat's tendency to bounce or hook.
Next, check how the boat reacts to an emergency maneuver. Again, while running at about 40 MPH, and with plenty of open area, jerk the steering wheel quickly a half-turn with a quick return to straight ahead. The boat may roll from chine to chine, but should quickly smooth out so that you can feel in control. If it continues to china walk, it is an indication the motor is moving relative to the boat and is likely to be more severe at higher speeds. A recheck of the steering system for excess free play is in order.
Increase your speed gradually, as long as you feel you have things under control. Be aware that as speed increases, certain conditions affecting the boat's stability can appear. There are several kinds of instability, each can affect your control of the boat. If any of these conditions is allowed to go un-corrected, you could possibly lose control of the boat. These conditions are:
Safety Warning: Do not over-power your boat by choosing an engine that exceeds the horsepower indicated on the boat's capacity plate. Over-powering could result in loss of control. If the boat does not have a capacity plate, see your dealer or manufacturer.
You must choose your boat. Since it is a performance rig, you will probably choose a boat with a horsepower capacity that matches your engine. Remember, if you try to over-power your boat, you might end up with a rig that is dangerously hard to control.
Regardless of type, the performance boat you choose should have a minimum of wetted surface (A), when running at full speed. Generally speaking, the less wetted running surface, the faster you will go.
FIG.1) A "V" bottom pad boat will give you good all-around performance. High performance "V" bottom pad boats usually incorporate a stepped transom (B). FIG.2) The stepped transom allows you to mount the engine higher. A higher transom height reduces the amount of gearcase in the water and improves boat performance. Watch your engine water pressure when experimenting with engine height!
FIG. 3) A modified tunnel design gives you high performance and good stability in rough water. It gives you some of the qualities both the "V" bottom and tunnel designs.
FIG.4) The sport tunnel is an adaptation of a racing design and is generally the fastest of all on smooth water. Once on plane, the tunnel design traps air which lifts the boat out of the water. The sport tunnel skims across the water rather than slicing through it. This hull design requires a skilled driver! The tunnel's air cushion makes the boat very sensitive to water conditions, changes in speed, turns, and changes in wind direction.
REMOTE CONTROL - The remote control shipped with your engine is designed specifically for your outboard. In most cases, the control incorporates start-in-neutral protection and an emergency ignition cut-off switch. The emergency ignition cut-off switch can prevent a runaway boat situation by stopping the engine's ignition if the driver leaves the operator's position unexpectedly.
Safety Warning: If you choose an alternate remote control, it must have start-in-neutral protection. This feature can vent injury resulting from unexpected motor operation. The emergency cut-off switch must also be installed in the circuit.
INSTRUMENTATION - To monitor boat performance you should consider an accurate tachometer, an extended range speedometer, and an engine trim indicator gauge. The tachometer will show you that the engine is always within the RPM operating range specified in your Owner's Manual. The speedometer will demonstrate speed changes caused by changes in engine height, propellers, and engine trim angle.
The engine trim indicator gauge allows the driver to reset the engine at a predetermined angle for optimum performance.
A 0-30 PSI engine water pressure gauge will allow you to monitor changes in the engine's cooling system. The engine water pressure gauge can provide an early warning of cooling problems caused by changes in engine height or trim angle.
When the driver is held firmly in place by a good seat, he can concentrate on controlling the boat! Your high performance boat should be equipped with a wraparound or bucket driver's seat. Also consider a solid footrest for your left foot to help hold you in place when the boat bounces.
Passenger seating should be similar and should be complemented by a handhold to help keep them in place.
Another way to improve boat control is to keep both hands on the steering wheel at all times. A racing
style foot throttle can be installed to handle engine speed settings. A lot of high performance boaters also put the trim switches on the footrest or steering wheel. Again, boat control is improved because you don't have to remove your hands from the steering wheel to change engine trim settings.
Your boat's fuel system must be carefully designed to provide adequate fuel flow for your high performance engine. Attention must be paid to fuel line diameters, connections, components, and system length. When assembled, the boat fuel system must be tested for fuel flow and restrictions. These tests are outlined in your engine's Service Manual.
A water separating remote fuel filter, is an important part of any boat fuel system. Some are designed specifically for two cycle applications. It can separate contaminants and moisture from the fuel supply without causing a significant pressure drop in the system.
As a performance consideration, the fuel tank should be located as close to the transom as practical. This will reduce the hull's wetted running surface and should increase top speed.
The engine's battery must be of heavy-duty construction and ample capacity. For larger engines, look for a
capacity of at least 500 CCA at 0o F with a 99 minute reserve at 80o F. Maintenance-free marine batteries can be used with larger engines equipped with fully regulated charging systems. Check the specific requirements of your engine outlined in your Owner's Manual or Service Manual.
Be sure the battery is installed in a vented container and that it is securely fastened to the boat. The use a cheap plastic battery tie downs in a high speed boat is more than a danger to the battery. Replace any plastic or light gauge battery tie downs with high performance or racing style tie downs. The less your battery moves, the less chance of loose connections and failure.
High performance boating requires the driver to give a high degree of attention to driving. Somewhere out there ahead of the boat there are always different wind currents, wakes from other boats, and debris floating low in the water. When you are moving fast almost any disturbance in the water can cause the boat to roll or yaw, requiring the proper corrective action. The faster you go the quicker things will happen. Only you can decide when you are going fast enough.
High performance boating is an exciting, exhilarating sport. The sport boater must, however, be considerate of others who may use the same waters. High performance boating requires a lot of water. Pursue your sport where you have plenty of room and your noise and wake won't annoy others. Make sure your pursuit of pleasure does not create a hazard or annoyance to nearby homeowners, fishermen, swimmers, water skiers, sailors or other powerboats. Make common sense and courtesy a regular part of your boating routine.
OMC Second Effort High Performance Division
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