what is faster a flat boat hull or a vee pad hull

[Okie]

As speed increases in light weight high performance craft - the interaction of the boat with the atmosphere becomes more important than the interaction of the running surfaces with the water in determining both lift and drag. Many very high speed "boats" use the hull/deck surfaces more for trapping or manipulating air and the running surfaces to minimize the effect of wave impact and provide control. To that end you will not see many high speed tunnel hulls with flat running surfaces. The Allison is a good example of a monohull that works the much the same way.

[mackid068]

Think: Turning, comfort...Conditions: Coastal

[cyclops]

I would go out on Mack's boat.

[mackid068]

Sorry, don't have one.

[riveramunizaga]

i get a 16 feet boat, 22º deep-v, 77" of beam, 140 hp and i woul like to know the modification to have the faster boat as posible, like pad and another things that you think.
i got a competition with a frend and he has a nitro 640 boat, with a 115 hp, and he said that is faster than me. but i get a deep-v original and i will change.

the nitro is like a flat amd has the shaft motor 5 " but above, has a 12" of wide pad and a tipe of inverter box into the transon and hull, about 5.5" of higth and 8" deep, and here star the pad.

plese help me

thanks

[Okie]

The pad type hull will generally perform better with limited horsepower at moderate speeds. The offset of the engine (on the Nitro) to the rear and above the aft end of the planing surface allows the combination to generate more bow lift at lower trim angles (from the setback) and reduces drag on the lower unit (from the raised height). On many hulls, that will produce more speed but the ideal ballance, distances and prop is unique to each situation. The running surfaces need to be fair and should not be flexing under load.

[mackid068]

Pad=Flat bottom? I would think that the v would have better handling and a more comfortable ride, but with low HP, the flat bottom will plane faster (i'm just restating other stuff, i think). Go with the V, it's better overall, aside from DRAFT.

[marshmat]

rivera- you seem pretty gung-ho on the add-a-pad thing. Might work, might not- you might find that it adds so much stern lift that the bow dips down, contact point moves forward and the boat sticks to the water and stuffs into waves. Then again, it could lift the boat high enough out that the pad starts cutting the waves and you get pounding. Of course, it could also work perfectly, your stern rising slightly and the boat levelling out with minimal wetted area.
The point is, it's pretty darn hard to predict how it will react without a few runs through CFD analysis on a CAD workstation. If it were my boat I'd look more at blueprinting the hull, tweaking the drive unit, etc. for speed rather than modifying the hullform.

[riveramunizaga]

i need help, no more confusions, plese anybody can to say me what size is better 6",8",10",12" wide pad to my boat.

[mackid068]

Medium is always best. Look at what marsh just said. Go for the eight foot, but if it works, try a larger one.