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## Re: Angle of vanishing stability

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• Message 1 of 8 , May 9, 2009
--- In BaylinerBuccaneerGroup@yahoogroups.com, Pb Pirate <pirate_pb@...> wrote:
>
> Try this sight http://www.sailingusa.info/cal__avs.htm
> Captain Ryan
>
> --- On Fri, 5/8/09, mtboat1 <mtboat1@...> wrote:
>
> From: mtboat1 <mtboat1@...>
> Subject: [BaylinerBuccaneerGroup] Angle of vanishing stability
> To: BaylinerBuccaneerGroup@yahoogroups.com
> Date: Friday, May 8, 2009, 9:27 PM
>
> Great thanks! I now need to find out the weight of a 240, the keel weight, and the ballast weight....and I don't really get the latter two. So far I have found at least three differant sets of figures for a 240. Three different weights...3000 lbs. 3800lbs. and 4000lbs. A figure of 1300 for keel weight, and 1050 for ballast. I worked it every way I could and still come out with a rediculously high number for stability. Ok I admit it I am not numerically oriented. I was banking on somebody all ready worked it out.
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> I am wondering if anybody can tell me what the numeric value in angle of vanishing stability is for a 74' 240. I hav3 been trying to calculate it out but can't really be sure of my figures. I get 147. That seems like it must be off.
>
• Utterly useless formula. So much more than beam and ballast is needed. Keeper keels with the same ballast would drastically change it for example. A wider
Message 2 of 8 , May 9, 2009
Utterly useless formula. So much more than beam and ballast is needed. Keeper keels with the same ballast would drastically change it for example. A wider beam near the waterline compared to a more vee-shaped hull would drastically change it, as would a taller or heavier rig. etc. Initial stability and vanishing stability are more art judged by eye than math.

Many of these formulas (such as theoretical hull speed and capsize screening formula) are mostly meaningless in the real world. I sailed my Santana20 above "hull speed" quite often, not just the occasional surfing but for distances on smooth water.

>
> I am wondering if anybody can tell me what the numeric value in angle of vanishing stability is for a 74' 240. I hav3 been trying to calculate it out but can't really be sure of my figures. I get 147. That seems like it must be off.
>

It's not very good. Reef early.
• ... Thanks. I will probably quit the calculations now. I am surely going to be careful but I would really like to know just how far over this boat heels
Message 3 of 8 , May 9, 2009
--- In BaylinerBuccaneerGroup@yahoogroups.com, "Phil Collins" <PandD_Collins@...> wrote:
>
> Utterly useless formula. So much more than beam and ballast is needed. Keeper keels with the same ballast would drastically change it for example. A wider beam near the waterline compared to a more vee-shaped hull would drastically change it, as would a taller or heavier rig. etc. Initial stability and vanishing stability are more art judged by eye than math.
>
> Many of these formulas (such as theoretical hull speed and capsize screening formula) are mostly meaningless in the real world. I sailed my Santana20 above "hull speed" quite often, not just the occasional surfing but for distances on smooth water.
>
>
> >
> > I am wondering if anybody can tell me what the numeric value in angle of vanishing stability is for a 74' 240. I hav3 been trying to calculate it out but can't really be sure of my figures. I get 147. That seems like it must be off.
> >
>
> It's not very good. Reef early.
>
Thanks. I will probably quit the calculations now. I am surely going to be careful but I would really like to know just how far over this boat heels comfortably, just a ballpark figure would do. I did the same thing in whitewater dories, just pushed it a little to see what is possible. Like my recent posts on reefing show...I am still a first time sailboat owner, and have been trying to cram as much as possible. Been working on reefing, and boom vangs and their functions...next up how to rig a preventer that can be set and trimmed from the cockpit.
• You have a high freeboard and a relatively narrow beam, it will take a knockdown and come back (provided it s not overloaded, especially up high, and the crew
Message 4 of 8 , May 10, 2009
You have a high freeboard and a relatively narrow beam, it will take a knockdown and come back (provided it's not overloaded, especially up high, and the crew isnt hanging on the lifelines and you ease the sheets to allow it to come up.) But a deeper keel would be a plus, so although I'd not worry about a knockdown, I'd worry if it went mast under water.

The round bottom shape and the shallow keel will give it less initial stability, it will heel earlier, but also a kindlier motion (not as important in a boat that doesnt/shouldn't go offshore.) But it does have enough ballast to self right. No worries.

Which reminds me, time to step onto my soapbox again. One of the best things you can do for your boat and your safety - if you have horn cleats (mooring cleats!) for the jib sheets - get rid of them. Install cam cleats. (Ratchet blocks on the lead cars is good too.) Nothing like getting hammered in a sudden gust and trying to undo cleated sheets... It's dangerous!

--- In BaylinerBuccaneerGroup@yahoogroups.com, "mtboat1" <mtboat1@...> wrote:
>
> --- In BaylinerBuccaneerGroup@yahoogroups.com, "Phil Collins" <PandD_Collins@> wrote:
> >
> > Utterly useless formula. So much more than beam and ballast is needed. Keeper keels with the same ballast would drastically change it for example. A wider beam near the waterline compared to a more vee-shaped hull would drastically change it, as would a taller or heavier rig. etc. Initial stability and vanishing stability are more art judged by eye than math.
> >
> > Many of these formulas (such as theoretical hull speed and capsize screening formula) are mostly meaningless in the real world. I sailed my Santana20 above "hull speed" quite often, not just the occasional surfing but for distances on smooth water.
> >
> >
> > >
> > > I am wondering if anybody can tell me what the numeric value in angle of vanishing stability is for a 74' 240. I hav3 been trying to calculate it out but can't really be sure of my figures. I get 147. That seems like it must be off.
> > >
> >
> > It's not very good. Reef early.
> >
> Thanks. I will probably quit the calculations now. I am surely going to be careful but I would really like to know just how far over this boat heels comfortably, just a ballpark figure would do. I did the same thing in whitewater dories, just pushed it a little to see what is possible. Like my recent posts on reefing show...I am still a first time sailboat owner, and have been trying to cram as much as possible. Been working on reefing, and boom vangs and their functions...next up how to rig a preventer that can be set and trimmed from the cockpit.
>
• ... Thanks Phil, good info. It just happens I know a Phil on this lake with the same boat and I am going to see if I can get him to take me out and get my
Message 5 of 8 , May 10, 2009
--- In BaylinerBuccaneerGroup@yahoogroups.com, "Phil Collins" <PandD_Collins@...> wrote:
>
> You have a high freeboard and a relatively narrow beam, it will take a knockdown and come back (provided it's not overloaded, especially up high, and the crew isnt hanging on the lifelines and you ease the sheets to allow it to come up.) But a deeper keel would be a plus, so although I'd not worry about a knockdown, I'd worry if it went mast under water.
>
> The round bottom shape and the shallow keel will give it less initial stability, it will heel earlier, but also a kindlier motion (not as important in a boat that doesnt/shouldn't go offshore.) But it does have enough ballast to self right. No worries.
>
> Which reminds me, time to step onto my soapbox again. One of the best things you can do for your boat and your safety - if you have horn cleats (mooring cleats!) for the jib sheets - get rid of them. Install cam cleats. (Ratchet blocks on the lead cars is good too.) Nothing like getting hammered in a sudden gust and trying to undo cleated sheets... It's dangerous!
>
> --- In BaylinerBuccaneerGroup@yahoogroups.com, "mtboat1" <mtboat1@> wrote:
> >
> > --- In BaylinerBuccaneerGroup@yahoogroups.com, "Phil Collins" <PandD_Collins@> wrote:
> > >
> > > Utterly useless formula. So much more than beam and ballast is needed. Keeper keels with the same ballast would drastically change it for example. A wider beam near the waterline compared to a more vee-shaped hull would drastically change it, as would a taller or heavier rig. etc. Initial stability and vanishing stability are more art judged by eye than math.
> > >
> > > Many of these formulas (such as theoretical hull speed and capsize screening formula) are mostly meaningless in the real world. I sailed my Santana20 above "hull speed" quite often, not just the occasional surfing but for distances on smooth water.
> > >
> > >
> > > >
> > > > I am wondering if anybody can tell me what the numeric value in angle of vanishing stability is for a 74' 240. I hav3 been trying to calculate it out but can't really be sure of my figures. I get 147. That seems like it must be off.
> > > >
> > >
> > > It's not very good. Reef early.
> > >
> > Thanks. I will probably quit the calculations now. I am surely going to be careful but I would really like to know just how far over this boat heels comfortably, just a ballpark figure would do. I did the same thing in whitewater dories, just pushed it a little to see what is possible. Like my recent posts on reefing show...I am still a first time sailboat owner, and have been trying to cram as much as possible. Been working on reefing, and boom vangs and their functions...next up how to rig a preventer that can be set and trimmed from the cockpit.
> >
>
Thanks Phil, good info. It just happens I know a Phil on this lake with the same boat and I am going to see if I can get him to take me out and get my confidence up.
• Phil, Good advise on not cleating off sheets. I lost a mast in Feb in a gale force wind on the gulf. Had a hard time uncleating and retriving all that cable
Message 6 of 8 , May 12, 2009
Phil,
Good advise on not cleating off sheets. I lost a mast in Feb in a gale force wind on the gulf. Had a hard time uncleating and retriving all that cable and rope wound up in the mast and sails.
Bob. (Just bought a 275).

--- In BaylinerBuccaneerGroup@yahoogroups.com, "mtboat1" <mtboat1@...> wrote:
>
> --- In BaylinerBuccaneerGroup@yahoogroups.com, "Phil Collins" <PandD_Collins@> wrote:
> >
> > You have a high freeboard and a relatively narrow beam, it will take a knockdown and come back (provided it's not overloaded, especially up high, and the crew isnt hanging on the lifelines and you ease the sheets to allow it to come up.) But a deeper keel would be a plus, so although I'd not worry about a knockdown, I'd worry if it went mast under water.
> >
> > The round bottom shape and the shallow keel will give it less initial stability, it will heel earlier, but also a kindlier motion (not as important in a boat that doesnt/shouldn't go offshore.) But it does have enough ballast to self right. No worries.
> >
> > Which reminds me, time to step onto my soapbox again. One of the best things you can do for your boat and your safety - if you have horn cleats (mooring cleats!) for the jib sheets - get rid of them. Install cam cleats. (Ratchet blocks on the lead cars is good too.) Nothing like getting hammered in a sudden gust and trying to undo cleated sheets... It's dangerous!
> >
> > --- In BaylinerBuccaneerGroup@yahoogroups.com, "mtboat1" <mtboat1@> wrote:
> > >
> > > --- In BaylinerBuccaneerGroup@yahoogroups.com, "Phil Collins" <PandD_Collins@> wrote:
> > > >
> > > > Utterly useless formula. So much more than beam and ballast is needed. Keeper keels with the same ballast would drastically change it for example. A wider beam near the waterline compared to a more vee-shaped hull would drastically change it, as would a taller or heavier rig. etc. Initial stability and vanishing stability are more art judged by eye than math.
> > > >
> > > > Many of these formulas (such as theoretical hull speed and capsize screening formula) are mostly meaningless in the real world. I sailed my Santana20 above "hull speed" quite often, not just the occasional surfing but for distances on smooth water.
> > > >
> > > >
> > > > >
> > > > > I am wondering if anybody can tell me what the numeric value in angle of vanishing stability is for a 74' 240. I hav3 been trying to calculate it out but can't really be sure of my figures. I get 147. That seems like it must be off.
> > > > >
> > > >
> > > > It's not very good. Reef early.
> > > >
> > > Thanks. I will probably quit the calculations now. I am surely going to be careful but I would really like to know just how far over this boat heels comfortably, just a ballpark figure would do. I did the same thing in whitewater dories, just pushed it a little to see what is possible. Like my recent posts on reefing show...I am still a first time sailboat owner, and have been trying to cram as much as possible. Been working on reefing, and boom vangs and their functions...next up how to rig a preventer that can be set and trimmed from the cockpit.
> > >
> >
> Thanks Phil, good info. It just happens I know a Phil on this lake with the same boat and I am going to see if I can get him to take me out and get my confidence up.
>
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