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Design, Building and Setup Secrets For Recreational tunnels, Offshore
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| Design Controls in TBDP Version 7 |
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Testimonials | Magazine Reviews | TBDP design features | Design Controls | Data Input | About TBDP | Latest Upgrade | Order |
Here's the kind of Design controls you have available to help optimize your tunnel hull performance…There's a lot here, and still more in the program!
| 1. Boat Data Input | 2. Weight & Measure Input | Four full, user-friendly input screens, with over 60+ input variables, for very precise control of your design and setup. | Excellent for any size of boat - from full-size F1 racing hulls to Recreational Tunnels and modified Vees to 60ft offshore catamarans and even RC model tunnels. Size, speed and setup conditions all accounted for by the software. |  |
| 3. Boat Setup Input | 4. Design Detail Input |
What's new 11/15/06 |
| ***TBDP©
reviewed by Scream & Fly magazine.
Check out the review at the S&F site, or dload
your own copy. ** Check out the manual of TBDP 'boat design input' data. Four full input screens, with over 60+ input variables, for very precise control of your design and setup. ** Get a FREE Video of the TBDP in operation. See the features, screens, performance graphics. ** Check out magazine reviews of new TBDP software in Hot Boat (USA) magazine. ** Check out magazine reviews of new TBDP software in Raceboat Int'l (UK) magazine. |
Design Data Inputs
1. Boat Data Input
| NAME | UNITS | DESCRIPTION back to top of page |
| Hull Design | ||
| Tunnel Height | (In) | Height of the tunnel at the aftmost location, measured from the tunnel roof to the aft sponson bottoms (running pads). |
| Tunnel Width | (In) | Width of tunnel, measured from inside sponson to inside sponson. |
| Wing Chord | (Ft) | length of the "wing" or aerofoil, measured from the leading (front) edge of the deck to the trailing (aftmost) edge, |
| WingThickness | (In) | Maximum thickness of the aerofoil, measured from the top of the deck to the tunnel roof, at the thickest point along the length. |
| Pad Width | (In) | Width of the sponson running surfaces (bottoms), measured from sheer (inside) to effective chine (outside). |
| Pad Deadrise | (Deg) | Angle of sponson running surfaces, measured from sheer to chine. |
| Deck Width | (In) | Width of the hull deck at the widest point. |
| Steps | ||
| Step Select | (Selection) | Select the use of sponson bottom design – no steps, one step, two steps |
| Step Length1 | (Ft) | Length of first (or single) step fore of transom (in feet), must be less than boat length |
| Step Length2 | (Ft) | Length of second step fore of first step (in feet), StepLength1 + StepLength2 must be less than boat length |
| Step Height | (Ft) | Height of STEP in sponson running surface, if one (or two) exist(s). |
| CenterPod | ||
| CtrpodSelect | (Selection) | Select whether the hull design includes a Mod-VP style CENTRE POD lifting surface (Yes/No) Hint: If there is NO CENTRE POD in the design, then the design is a conventional tunnel hull configuration, and NOT a Mod-VP design). |
| CtrpodLength | (Ft) | When it exists, the length of Mod-VP style CENTRE POD lifting surface, located centrally in the tunnel. This design feature generates additional hydrodynamic lifting capability, increases stability. It adds water drag and reduces aerodynamic lift. |
| PodWidth | (In) | Overall width of CENTREPOD, from chine to chine. |
| PodHeight | (In) | Height difference between SPONSON and CENTREPOD, positive means CENTREPOD is higher from waterline than SPONSONS. |
| PodDeadrise | (Deg) | Angle of CENTREPOD running surfaces (bottoms), measured from keel to chine. |
| NAME | UNITS | DESCRIPTION back to top of page |
| Lengths | ||
| Boatlength | (ft) | Overall length of hull, measured from sponson tips to aftmost deck or sponson point. |
| Driverlength | (ft) | Location of the driver, measured from the transom to the driver centre. |
| Motorlength | (ft) | Location of the motor, measured from the transom to the motor centre. May be either fore (+), or aft (-) of the transom. |
| Fuellength | (ft) | Location of the fuel, measured from the transom to the fuel centre. |
| Misclength | (ft) | Location of additional equipment that is concentrated mostly in one location, such as hydraulic systems, ballast, etc., measured from the transom to the (average) load centre. |
| Motor Height | (%) | Height of MOTOR from water surface to the top of the engine casing/housing. |
| Lower Unit Height | (%) | Height of lower
unit "bullet" above/below sponson running pad. (+) is above, (-)
is below. Hint: Most high performance setups start with as little of the lower unit bullet in the water as possible, thus reducing drag significantly. Surface piercing propellers and low level water pick-ups make this fiesalbe. LwrUnitHeight values of +0.5in to +1” (above sponson running surfaces) are possible in very high performance applications. Without low water pickup, or when low end torque is a requirement, then LwrUnitHeight values of –0.5 to -2” (below sponson running surfaces) is applied. |
| Weights | ||
| Boatweight | (lbs) | Total weight of hull (only), including rigging, but excluding motor, fuel, driver, and other significant additional equipment. This weight should include all rigging weights that have not otherwise been accounted for. |
| Motorweight | (lbs) | Total weight of motor, drive unit, propeller, and accessories such as hydraulic trims, plates, etc that are attached to or built in at the motor. |
| Driverweight | (lbs) | Weight of driver with all clothing and safety equipment. |
| Fuelweight | (lbs) | Weight of fuel tanks and normal fuel supply. |
| Miscweight | (lbs) | weight of additional concentrated equipment such as hydraulic systems, ballast, etc., that are located at LENGTH MISC . |
| NAME | UNITS | DESCRIPTION back to top of page |
| Design Analysis | ||
| Optimization Configuration |
(-) | CONFIGURED FOR
ANGLE OPTIMIZATION - the program will find the optimum Angle of Attack
required to attain performance at the specified velocity, while satisfying
the specified power rating (POWER MAX). The predictive performance
solution will be presented for each of ten (10) specified velocities as
defined by STARTVEL and VELOCITY INCR'T.
CONFIGURED FOR POWER OPTIMIZATION - the program will find the required (minimum) POWER at the specified velocity, for the specified Angle of Attack, ANGLESTART. The predictive performance solution will be presented for each of ten (10) specified velocities as defined by STARTVEL and VELOCITY INCR'T. In addition, full power (POWER MAX) will be used to estimate ACCELERATION rates and elapsed TIME to each VELOCITY increment. This feature is a most powerful tool in evaluating detailed design and hull setup performance characteristics. CONFIGURED FOR VELOCITY OPTIMIZATION - the program will find the maximum velocity attainable for the specified Angle of Attack, while satisfying the specified power rating (POWER MAX). The input value of STARTVEL will be used only as the first "guesstimate" of the solution. |
| Accuracy | (%) | Selected allowable percent deviation for the OPTIMIZATION analysis, will define how close the program iteration process will attempt to come to specified maximum power rating, before printing a solution; a smaller ACCURACY DEF gives higher accuracy, but takes longer; too small an ACCURACY DEF may make it too difficult to optimise a solution. |
| Start Velocity | (Mph) | Starting (lowest) velocity of a series of ten (10) velocities that ANGLE OPTIMIZATION or POWER OPTIMIZATION analyses will use. The predictive performance solutions will be analysed for this velocity and the increasing velocities at specified increments (VELOCITY INCR'T). |
| Velocity Inc | (Mph) | increment used in the series of ten (10) velocity steps analysed with ANGLE OPTIMIZATION or POWER OPTIMIZATION analyses. Ineffective if VELOCITY OPTIMIZATION analysis method is used. |
| Velocity Range Calculator |
(Selection) | [HELP TOOL] You can use the Velocity Range Calculator to automatically determine the incremental velocity steps to be used in the analysis. Change any of the variables, and the others will be changed automatically. Close the window to transfer the values back to the input screen. |
| Start Angle | (degrees) | For ANGLE OPTIMIZATION, this is used by the optimizing algorithms as a starting estimate for the Angle of Attack of the running surfaces (sponson pads). The program will find the angle of attack for the specified velocity while still satisfying POWER MAX. The closer your first "guesstimate" of ANGLESTART is to the optimum angle of attack (WANGLE), the faster the optimising analysis procedure will be.For VELOCITY OPTIMIZATION, the program uses this specified angle of attack to calculate the velocity that will satisfy POWER MAX. For POWER OPTIMIZATION, the program uses this specified angle of attack to calculate the POWER required to maintain specified velocity increments, or it uses the WAngle input in the ACCEL MODEL (see below). |
| Acceleration Model |
(selection) | [HELP TOOL] This is an optional input. The default (Constant WAngle) is used for analysis if you don't change it. Input the WAngle of attack for each Velocity in the performance range. For POWER OPTIMIZATION, the program simulates acceleration and elapsed time based on power available, and the WAngle of attack. Three (3) selections are available: (1) Constant WAngle: Uses the same WAngle for all velocities. StartAngle input is used automatically. This gives a bounding simulation of achievable acceleration.(2) Straight-Line WAngle: A more realistic acceleration and elapsed time simulation can be modelled by inputting a specific WAngle for each Velocity in the performance range. A reasonable representation of this WAngle is provided as a "Straight-Line" increase of WAngle from zero (0 degrees) up to the input Startangle(3) User-Fit: A third simulation "User Fit" can be selelected, allowing the user to input a specific WAngle of attack for each velocity in the performance range. This will be most accurate, but is for advanced users. |
| Conditions | ||
| Power Max | (Hp) | shaft horsepower used as basis for all OPTIMIZATION analyses. (Note that shaft HP is usually about 10% less than the maximum powerhead HP on an outboard). Predictive performance solutions will be based on this HP rating, within the specified solution tolerance (ACCURACY DEF). |
| Powereff'yfac | (%) | efficiency factor in the transmittal of POWER from prop shaft into propulsive force. This includes efficiency losses due to gear/transmissions as well as propeller inefficiencies, and is usually between 0.5 --> 1.0. This value is used in the calculation of ACCELERATION and estimated ELAPSED TIME to accelerate between incremental velocities, and will not affect any other performance results. |
| RPM Max | (RPM) | Maximum RPM setting/allowable on engine (input directly or from MotorSelection Wizard database). |
| Altitude | (ft) | altitude above sea level, of expected performance conditions. |
| Water Type | (Selection) | expected water conditions - sea water or fresh water. |
| Drive Unit | ||
| Drive Type | (Selection) | [HELP TOOL] Select the type of lower unit (outdrive) you are using, from a drop-down list of all manufacturers. All of the dimensional detials (below) of the selected drive are automatically input to the remaining fields, when you make your selection. You can also select to input your own specific outdrive design dimensions. |
| Drive Number | (Selection) | The number of lower unit drives (no. of engines). Select: One (default); Two or Three drive units. |
| Skeg Width | (In) | average width of motor lower unit/outdrive skeg (leading edge of skeg to back of skeg). |
| Skeg Length | (In) | length of motor lower unit/outdrive skeg (top of skeg to bottom of skeg). |
| Skeg Thickness | (In) | thickness of motor lower unit/outdrive skeg (thickness of the skeg plate). |
| Torpedo length | (In) | length of motor lower unit/outdrive torpedo housing (leading edge of torpedo to aft edge of torpedo, at prop shaft). |
| Torpedo diameter | (In) | diameter of motor lower unit/outdrive torpedo housing (in section). |
| Gear Ratio | (ratio) | gear ratio of Lower Unit/drive unit (input directly or from MotorSelection Wizard database). |
| NAME | UNITS | DESCRIPTION back to top of page |
| Spray Rails | ||
| Spray Height | (In) | Height of outer sponson SPRAY RAILS, if they exist, measured from aftmost bottom of sponson running surface. Usually are seen about 1/2 way between sponson bottom and deck (sheer clamp). Outer spray rails can improve hydrodynamic lift at lower CLW's (lower velocities) and reduce spray drag. |
| Spray Width | (In) | Width of outer sponson SPRAY RAIL, if they exist. Usually about 2 inches wide on IOGP and family (Mod-VP) type hulls - wider on Ocean racers. |
| Sprayfac | (-) | Factor of influence of water spray on hydrodynamic lift and drag. Affected somewhat by effectiveness of spray rails, chine steps, etc. |
| AeroFoil | ||
| Angle Inc | (Deg) | Incremental angle between running surface (sponson pads) and the wing chord. This is usually the additional (if any) angle of attack of the wing chord compared to the angle of the running surfaces (e.g. the angle of the wing chord if the running surfaces were at an angle of zero). |
| AngleInc Calculator |
(Selection) | [HELP TOOL] You can use the AngleInc Calculator to automatically determine the incremental angle of attack of your hull design. The AngleInc is the difference in angle between the aerofoil chord and the sponson bottoms (when sponsons are at zero angle). Input the height to chord at the leading edge of the wing; and the height to chord at the trailing edge of the wing; the Calculator will determine the incremental angle. The calculated AngleInc will be automatically transferred to the input field when you close the Calculator window |
| Cowling | ||
| Cowltype | (-) | type of cowling design, either:(1) OPEN faired front and rear cowlings, with exposed driver cockpit. (2) CANOPY type with integral or closed, faired cockpit enclosure, like with a safety cell. (3) NONE open cockpit with no fairings. |
| Cowlheigh rear | (in) | Height of REAR COWL from the deck surface to the maximum point above the deck surface. |
| Cowlheight front | (in) | Width of COWL or fairing at the widest point. |
| Cowlwidth | (in) | Width of COWL or fairing at the widest point. |
| Open Deck | (ft) | Length of open (unobstructed) deck fore of the cockpit. |
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