Subject: [harryproa] Leeway prevention
From: "Colin" <colcampey@hotmail.com>
Date: 1/2/2011, 7:21 AM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

 

Hi Dennis,

If steering without rudders works, what about a Leeboard for leeway prevention - only when close-hauled, symmetrical for use in both directions, pivoting on a pin midway along the top of the leeward side of the leeward hull. It's held down with cords ("fore and aft") which go to those cleats which give under impact.
With a schooner, the pin could go right through to the windward side of the (reinforced) hull.
When off the wind, the board is up out of the water.

I'm thinking of using one on my 6 meter "Cantarry". Might wait til I see how yours goes :-)

Cheers,

Col

--- In harryproa@yahoogroups.com.au, Dennis <dec720@...> wrote:
>
> Yeah, in my readings I found it very interesting how the traditional Polynesian boat did almost all their travels with balance like you suggest. I'd really like that idea with respect to the schooner configuration. I think most of my analysis for sizing was for leeway prevention... Not turning. I'm hoping I can get the hull out of the leeway prevention job... Running clean.
>
> -----Original Message-----
> From: Colin
> Sent: Friday, December 31, 2010 4:49 PM
> To: harryproa@yahoogroups.com.au
> Subject: [harryproa] Re: down south over new year's
>
>
>
> Happy New Year to all.
>
> Rare Bird's rudder repairs saga is almost at an end - delayed recently by incessant rain. Hopefully sailing again this month.
>
> Dennis, commiserations for your weather too. With regard to MLM steering, have you considered seeing how much you can steer with just the sails, before you add the rudders? You may be able to achieve a stable angle to the wind just through sail balance, with or without just a little help from a steering oar.
>
> Cheers,
>
> Col Campey
>
>
> --- In harryproa@yahoogroups.com.au, Dennis <dec720@> wrote:
> >
> > Well... I'm here to tell you... Its the coldest damn winter I've seen here in Atlanta in the past 20 years! Guess... Obama fixed global warming in his first term.
>
> Would love to be there to be a deck hand. I'll be thinking of you... You bum. :(
>
> Dennis
> >
> > -----Original Message-----
> > From: Doug Haines
> > Sent: Thursday, December 30, 2010 2:04 AM
> > To: harryproa@yahoogroups.com.au
> > Subject: [harryproa] down south over new year's
> >
> > Well i hear there is snow around the US and europe.
> > As per usual Western Australia is dry and sunny - too sunny, UV ra`diation is quite strong.
> > Anyhow I have a good looking weahter window coming up and it should be nice down in Albany where the boat is over the weekend, and then I see a forecast of very low sell and nice easing off winds.
> > Hopefully a clean run all the way back around cape Leeuwin, past Margaret River, then into the coastal plain - this is where the cliffs and rocks stop and the shore line is a more friendly sand dune.
> >
> > Doug
> >
> > --- On Thu, 30/12/10, Doug Haines <doha720@> wrote:
> >
> > From: Doug Haines <doha720@>
> > Subject: Re: [harryproa] Re: Hull slenderness ratios ww hull lengths
> > To: harryproa@yahoogroups.com.au
> > Date: Thursday, 30 December, 2010, 11:56
> >
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> > well you might save 10-15kgs, by not having an extra 2m of b0w.
> >
> > --- On Thu, 30/12/10, tsstproa <bitme1234@> wrote:
> >
> > From: tsstproa <bitme1234@>
> > Subject: [harryproa] Re: Hull slenderness ratios ww hull lengths
> > To: harryproa@yahoogroups.com.au
> > Date: Thursday, 30 December, 2010, 2:26
> >
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> > How do you save weight by having shorter hull? If that's the hull you have all your gear stowed in and its the hull you sail from?
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> >
> > --- In harryproa@yahoogroups.com.au, Doug Haines <doha720@> wrote:
> >
> > >
> >
> > > Thinking now - maybe higher bridge deck/beam clearance.
> >
> > > SWome splash guards deflecting spray and white water and even green (or can it be blue as well) water out of cockpit.
> >
> > > The El camper is only 8:1 ww hull compared with 12:1 harry ww hull. I wonder what Sol and $Rapscallion length to beam ratios are?
> >
> > >
> >
> > > A little extra lenght or buoyancy or free board and a pointier bow is what i'd want.
> >
> > >  
> >
> > > I don't mind saving weight with a short ww hull, but it has to go THROUGH the waves almost as much as the lw hull (which performs sweetly in slicing through chop).
> >
> > >
> >
> > > I was sthinking say doing somethging based on solitarry, with two beams and schooner.
> >
> > > Maybe not 8m wide, maybe like about 6m wide.
> >
> > > Something similar to Rob's ww cabin, but the way that the cabin ends just right on the bow with the flares all coming in to that point and the beams as well , it just looks like there is a anothere forward section missing fromit.
> >
> > > Another 2m with a foredeck would be nicer I reckon.
> >
> > > How much extra weight is that?
> >
> > > 10kgs?15 kgs?
> >
> > > Not much more.
> >
> > > So that is a 7m ww hull, plus 2x2m = 11m ww hull all up.
> >
> > > I think a Vis is 12m.
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> > >
> >
> > > Doug
> >
> > >
> >
> > > --- On Wed, 29/12/10, proaconstrictor <proaconstrictor@> wrote:
> >
> > >
> >
> > > From: proaconstrictor <proaconstrictor@>
> >
> > > Subject: [harryproa] Re: Hull slenderness ratios
> >
> > > To: harryproa@yahoogroups.com.au
> >
> > > Date: Wednesday, 29 December, 2010, 19:51
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> > > > I mean ideally you would have a ww hull as narrow as the lw wouldn't  you?
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> > > > I fact why not a 15m ww hull as well?
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> > > That presupposes that longer hull = better. That isn't always the case. But it becomes a difficult issue to discuss when the objectives of the various parties aren't agreed upon.
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> > > When the HP is sailing full throttle the main hull is being lifted up, and the LW is being pressed down. So relative to drag, how dissimilar are their resistances. relative to longi stability, one can always ask the further question that while one could extend the WW hull waterline length would that weight, slight as it could be, be better spent extending the length of the LW hull which is the one getting tossed around by the rig and various drive action.
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> > > It is assume in the Multihull case often, that longer and narrower are always faster. That isn't true of all boats. Boats that are paddled can start to experience increased drag when they assume higher wetted surface areas. Another complex issues with lots of types. While this might not be an issue when heavily driven, I wonder if two equally long hulls will perform as well it light conditions.
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> > > There used also to be some stuff about how the proa hulls encounter waves, that suggested that shorter WW hulls where better. I leave that to those who are interested in making the case. What about shunting, is there any advantage there to a shorter hull given the different path it gets dragged through, and rocker.
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> > > There is also a lot of posturing on over and under length issues. What waterline length is the length for record, and for comparison purposes. is a Harryproa a 20+ foot boat with a 40' waterline, or a forty foot ama with a really short main hull. What features have been optimized to create what relative benefits.
> >
> > >
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> [The entire original message is not included.]
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