----- Original Message -----From: tsstproaSent: Monday, September 19, 2011 9:48 PMSubject: [harryproa] Re: Video of Blind dateInduced heel angle would anticipate heel force either by precanting hull Like on echeleon for example with a 10-15 degree induced cant so when heeled hull will see 0 cant angle. But there are two other ways in which to compensate for heel force buoyancy and ride height as well. Get all three right an you have reduced the negative effects of heeling , not to be confused with reducing heel force. Hopefully the force is still there just not being absorbed by heeling of the hulls. Instead driving the boat forward on hulls intended foot print. Basic principal really flat is fast. But when you have more than one hull flat takes on a whole different dimension.
Todd
--- In harryproa@yahoogroups.com.au, "Peter Southwood" <peter.southwood@...> wrote:
>
> How does it differ from heel?
> Cheers,
> Peter
>
> ----- Original Message -----
> From: tsstproa
> To: harryproa@yahoogroups.com.au
> Sent: Monday, September 19, 2011 7:29 PM
> Subject: [harryproa] Re: Video of Blind date
>
>
>
> rotational direction of hull due to sail heeling force. When you have canceled out ever other force by design or counter measure except rotation of hull due to sail force
>
> http://www.youtube.com/watch?v=8NO385N9sqU
>
> Todd
>
> --- In harryproa@yahoogroups.com.au, "Peter Southwood" <peter.southwood@> wrote:
> >
> > What is heel induced cant?
> > Cheers,
> > Peter
> > ----- Original Message -----
> > From: tsstproa
> > To: harryproa@yahoogroups.com.au
> > Sent: Monday, September 19, 2011 5:22 PM
> > Subject: [harryproa] Re: Video of Blind date
> >
> >
> >
> > To me its not about the spray/spume Its about efficiency and what looks and sonunds like to me the hull is topping out on its ability to push any more water aside with out requiring quit abit of extra force. In the the video someone said 20-25 knots of wind and they where doing 16knots average on a beam reach.
> >
> > My question is what happens to boat speed and boat trim when heading up in those same conditions.
> >
> > Stopping the heel induced cant with a little extra buoyancy instead of weight to windward couldn't hurt. Reducing draft of leeward hull when static and improving anti cant angle when active.
> >
> > Todd
> >
> > --- In harryproa@yahoogroups.com.au, Rick Willoughby <rickwill@> wrote:
> > >
> > > Gardner
> > > I believe there is merit in a little rocker but not so much to bring
> > > the stem clear of the water in static condition.
> > >
> > > Initially the chine at the bow is submerged. If the dynamic lift is
> > > significant then the chine could be clear of the water at speed.
> > > This will reduce the water sheeting up the sides and forming spume.
> > >
> > > However the energy loss in forming spume is insignificant - maybe 1
> > > or 2W compared with the 10,000+W to achieve that speed on that boat.
> > > I cannot see any reason to be concerned about a bit of spume coming
> > > of the lw bow. The spume does not even get near the helm position.
> > > If it was a great concern then you could mould spray rails into the
> > > bows but they make building more complex and add more weight.
> > >
> > > Rick
> > > On 19/09/2011, at 11:29 AM, Gardner Pomper wrote:
> > >
> > > > Rick,
> > > >
> > > >
> > > > I am afraid that I am not following your reply. I get that it won't
> > > > slam, but I am not sure if you are agreeing with a little rocker or
> > > > disagreeing. I am trying to reduce the spray from the bow entry and
> > > > hope that it will get some lift. Do you think that is a good idea
> > > > or not?
> > > >
> > > > - Gardner
> > > >
> > > > On Sun, Sep 18, 2011 at 9:06 PM, Rick Willoughby
> > > > <rickwill@> wrote:
> > > >
> > > > Gardner
> > > >
> > > > I put rocker in the ends but there is still positive draft at the
> > > > ends in static condition. A lw hull with flat bottom starts to get
> > > > significant dynamic lift above 10kts. Depending on the
> > > > displacement and length 50% or more of the displacement could be
> > > > supported dynamically. In this condition the stem would be above
> > > > nominal water level.
> > > >
> > > > A hull that is 12m long and maybe 0.4m wide on the bottom is not
> > > > going to slam. It needs a substantial proportion of the length
> > > > immersed to generate the dynamic lift. There might be a bit of
> > > > wave slap in ripples at high speed but it will not be slamming.
> > > > The lift coefficient can never get very high because it takes only
> > > > 1 degree or so of bow up trim before the immersed length is reduced
> > > > and the lift area starts to reduce. If the hull has a high flared
> > > > bow, the sides might pump as they are forced into waves - geed
> > > > reason to keep reserve buoyancy in the ends low. A lightly loaded
> > > > ww hull with a flat bottom is more inclined to pound at speed so
> > > > slight "V" might improve it - really only an issue if you intend to
> > > > go close to flying a hull.
> > > >
> > > > Rick
> > > >
> > > > On 19/09/2011, at 9:23 AM, Gardner Pomper wrote:
> > > >
> > > >>
> > > >> I was also watching the spray off the lee bow in the video. It
> > > >> looks like the sharp bow ends up having the water crawl up it
> > > >> vertically. It made me think that maybe just a little bit of
> > > >> rocker would both cut down on the spray and also push the bow up a
> > > >> little. Wouldn't a bow up force be good?
> > > >>
> > > >>
> > > >> I thought that Rick had an idea along the same lines; if the
> > > >> "keel" gets flattened out a bit and the "foot" of the bow gets
> > > >> trimmed so that it slants up from a couple feet back to maybe 6"
> > > >> above the nominal waterline, there would be an upwards push
> > > >> without changing the buoyancy much, since the lee bow is so fine
> > > >> at that point. I know a flat bottom is typically a slamming
> > > >> concern, but the flat section is at most a foot or so where the
> > > >> water would be hitting it, so I don't see how it can slam.
> > > >>
> > > >> Thoughts?
> > > >>
> > > >> - Gardner
> > > >>
> > > >> On Mon, Sep 12, 2011 at 4:24 PM, tsstproa <bitme1234@>
> > > >> wrote:
> > > >>
> > > >> Wow I'm impressed on how rock solid it is while sailing over all
> > > >> the boat looks at ease sailing at speed. Though to me just an
> > > >> observation , cant feel what the boat is doing , just looks like
> > > >> the leeward hull seems to be tring to hard going through the
> > > >> water. Is it topping out in its max speed potential for hull form
> > > >> or can the hull be pushed harder above 15knots with out any ill
> > > >> effect just more spray. I'm not one to worry much about spray as
> > > >> long as I'm not standing in the direct path of a fire hydrant!
> > > >>
> > > >> Same look here with this hull at 15 knots.
> > > >>
> > > >> I thought you said your boats are dry Rob :0
> > > >>
> > > >> http://www.youtube.com/watch?
> > > >> v=5pOsgqrO59A&feature=BFa&list=PL16877B8994035140&lf=results_main
> > > >>
> > > >> Todd
> > > >>
> > > >>
> > > >>
> > > >> --- In harryproa@yahoogroups.com.au, "Henny van Oortmarssen"
> > > >> <henny@> wrote:
> > > >> >
> > > >> > As promised I have made a video of Blind Date, now sailing with
> > > >> her renewed "old" rudders, sailing last Sunday September 11 under
> > > >> the lee shore of the dyke between Lelystad and Enkhuizen, wind
> > > >> from S to SW Bf. 4 to 5, max speed 12.8 kn, see
> > > >> >
> > > >> > http://www.youtube.com/watch?v=wftyqI2aJlo
> > > >> >
> > > >> > On my blog you can also find an image of the track and speed.
> > > >> Unfortunatly I cannot figure out yet how to show this in Google
> > > >> Earth (to be continued)
> > > >> >
> > > >> > http://framsblog.wordpress.com/2011/09/12/sailing-with-blind-
> > > >> date-a-harryproa-visionnary/
> > > >> >
> > > >> > Not to bad compared with BD's second generation rudders. My
> > > >> experience with BD so far was with these second generation
> > > >> rudders. They just didn't work. With the latest modifications,
> > > >> reinforcing the original rudder sleeves by Rudolf and Nol to
> > > >> replace the original rudders and removing these second generation
> > > >> rudders by Nol and me, BD is now reborn and healthy again.
> > > >> >
> > > >> > Only for remembering purpose, and only for that ;-) below is a
> > > >> short video of the second generation rudders (they now RIP)
> > > >> >
> > > >> > http://www.youtube.com/watch?v=bSnrijWJ5Pk
> > > >> >
> > > >> > Henny van Oortmarssen
> > > >> >
> > > >> >
> > > >> > ----- Original Message -----
> > > >> > From: Henny van Oortmarssen
> > > >> > To: harryproa@yahoogroups.com.au
> > > >> > Sent: Monday, September 05, 2011 6:03 PM
> > > >> > Subject: {Disarmed} Re: {Disarmed} Re: [harryproa] Re: Wantoo vs
> > > >> Expeditionarry
> > > >> >
> > > >> >
> > > >> >
> > > >> >
> > > >> >
> > > >> > I guess he first has to recover from the work last Saturday ;-) ;-)
> > > >> >
> > > >> > Nol and I removed the new rudders of BD and that was hard work.
> > > >> Rudolf had made it to last for centuries. Real hard work and still
> > > >> a lot of itch over my whole body.
> > > >> >
> > > >> > So Nol and I have the appointment to undergo a tough test in
> > > >> high winds with the "new" old rudders, as soon as we both have
> > > >> time and the wind is blowing 20kn or more. I promise to take a
> > > >> video camera with me.
> > > >> >
> > > >> > To be continued.
> > > >> >
> > > >> > Henny van Oortmarssen
> > > >> >
> > > >>
> > > >>
> > > >>
> > > >>
> > > >
> > > > Rick Willoughby
> > > > rickwill@
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > > Rick Willoughby
> > > rickwill@
> > >
> >
> >
> >
> >
> >
> >
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