I don't doubt that a wider cross section bottom hull will plan up quicker for a given weight to weight length to length hull comparison.
Just because your planing riding high in the water doesn't mean your faster. What I'm in doubt of is which one is faster for given conditions with least amount of fuss. (Fuss) All the technical bits Nasa engineered super foils {chuckling} and added leaver's for all the control bits.

Sorry Offsets are only printed out and no printer for that computer. The hull program is old and I'm no computer wiz...The program only prints on the older style printer connections or if you can find the adapter. I was never able to print out anything from this program. It does give me bulkhead half breadths and heights from base line on screen with out having to print them out. So I take bulkhead measurements ever 12-24'' depending on hull length for most of my Proa hulls I take 24'' and center bulkhead measurements. If you want I could give you the bulkhead measurements.

It would be easier to distinguish were your coming from if you just give your own philosophy in hull design vs number crunching anyways. In a lake, in a pond, in a bay, vs open ocean and at what range of conditions in the body of water play huge on a design.

I like your philosophy doing more with less. This to is hard to define. To some its like saying what if!

Todd

--- In harryproa@yahoogroups.com.au, Rick Willoughby <rickwill@...> wrote:
>
> Todd
> No need to speculate on the performance difference. Post the offsets
> and I will compare the resistance in displacement mode. At the
> higher end above 15kts the flat bottom will benefit from more lift
> due to planing than the V section.
>
> Rick
> On 16/05/2011, at 4:18 PM, tsstproa wrote:
>
> > No I produced a reasonably shaped 20' V hull for 400lb dis. 30''
> > sheer height, 20'' beam, that sits on a 14'' draft. With a 10''
> > waterline beam
> >
> > Square hull bottom 20' hull 20''sheer height,14'' beam with a 14''
> > waterline beam.
> >
> > V and Square bottoms are both flat panels/slab sided. Why do you
> > think the larger cross section would be more efficient just because
> > of its lift coefficient?
> >
> > V hull with greater lateral surface area on a smaller narrower
> > cross section is efficiency. Requiring even small boards for
> > steering vs lateral resistance.
> >
> > Todd
> >
> > --- In harryproa@yahoogroups.com.au, Rick Willoughby <rickwill@>
> > wrote:
> > >
> > > Todd
> > > The V hull will produce lift but nowhere near as efficiently as a
> > > cambered centreboard. I also doubt that it will be more efficient
> > > than a flat bottom hull. Using your numbers you have increased the
> > > wetted surface more than 30% just to increase the lateral surface
> > > area. There is a huge cost in terms of extra hull drag. The lift
> > > coefficient for a deep V section could easily be half that of a flat
> > > panel. So 18sq.ft V may not be any better than 7sq.ft flat.
> > >
> > > I have some reasonable models for flat panel planing and Savisky for
> > > planing V hulls but it stops at 35 degrees deadrise for vertical
> > > lift. I know anything steeper than 45 degrees deadrise will dig in
> > > rather than slip sideways. So if the deadrise is greater than 45
> > > degrees it should be good at preventing leeway but still not as good
> > > as a slab side.
> > >
> > > Rick
> > >
> > >
> > > On 16/05/2011, at 2:11 PM, tsstproa wrote:
> > >
> > > > Hull length for length. Hull displacement for displacement.
> > > >
> > > > Say on a 20 foot hull with a 400lb displacement.
> > > >
> > > > V hull with a 13'' draft and Square bottom hull with a 6'' draft.
> > > >
> > > > V hull 38sqft wetted surface area, square bottom hull 28sqft
> > wetted
> > > > surface area.
> > > >
> > > > V hull with 18 sqft lateral area and Square bottom hull 7 sqft
> > > > lateral area.
> > > >
> > > > V hull skidding out and not producing lift I doubt it!!!
> > > >
> > > > V hull with more than double the area how do you figure it would
> > > > and not produce lift?
> > > >
> > > > Also at high angles of heel do you see the difference in under
> > > > water plane shape? The wider the square bottom hull becomes the
> > > > more defined is becomes.
> > > >
> > > > Placement of rudders on beam is more about convenience for the
> > > > models. The rudder placement on the model in this clip is to close
> > > > to the hull. If you look at the end of the clip. The same model
> > > > with the reverse flow sail design on it you might see what looks
> > > > like rudder ventilation. I use rudders to test balance of hull to
> > > > sail. Not to test foil designs. Except of course the large leefoil
> > > > and windward foil design models.
> > > >
> > > > Todd
> > > >
> > > >
> > >
> > > Rick Willoughby
> > > rickwill@
> > > 03 9796 2415
> > > 0419 104 821
> > >
> >
> >
>
> Rick Willoughby
> rickwill@...
> 03 9796 2415
> 0419 104 821
>