Re: [bolger] Re: bolger box stability?
And yet wooden masts have some bouyancy which, at least on small boats, limits the capsize roll to about 100 to 110 degrees. Bear in mind that boats in sheltered waters get knocked down by wind, while in open water, a boat may be capsized by wind and/or wave action (try playing in the surf if you doubt this!)
John T
John T
----- Original Message -----
From: Nels
To:bolger@yahoogroups.com
Sent: Sunday, September 05, 2004 12:33 AM
Subject: [bolger] Re: bolger box stability?
--- Inbolger@yahoogroups.com, "Jason Stancil" <jasonstancil@h...>
wrote:
> > An overlooked area that can really make a boat stable when
> inverted
> > is a large mast and all the standing wire rigging.
************************
Of course there is an error in the above - replace the word "stable"
with "unstable"
> I've thought about this as an 20' 80lbs aluminum keel is kinda
> disheartning....wonder if the foam would make it unstable when up
> right. Ithought of puting a bunch of those foam noodles kidsuse in
> pools.
probably the best is to plug most of the holes so water can't get in.
It should come back up before it gets all filled with water.
i bet you will have a wider range of stabiliy than a lot of slack
bilged, low-sided centerboard production boats!
>
> The best way to increase the range of stability is
> > with lead ballest down low. MICRO is a prime example:-)
> Hey i'v got the keel batten scarfed and ready to go as well as a
> foam mock up of the keel sheathing. However, i also have a martha
> jane leeboard sitting in my garage :)..........i think i'm going
for
> the keel mainly because my 200 sqft MJ sail is too much for the
> internally balasted micro/jukebox navigator.
Howcum only one leeboard? Sounds like you should have built a MJ
instead;-)
>
> > I have read many accounts about how quickly a MICRO rights itself.
> Go knock that thing down andletme know how it goes!
I have never heard of one actually getting knocked flat. Bernie
Wolfard tells about an incident he had when he had the main sheet
cleated and a gust hit. It heeled over and back up so fast he nearly
went overboard. He had two neophytes with him and they just figured
that he did it to scare them, little realizing he had scared himself
a lot more:-)
Another guy was turning a new inverted hull upright by putting it on
a spindle device and raising it up and got a surprise when he and
several friends were rotating it upright. Lots of leverage in that
little keel I guess.
>
> Jason
> PS.....Nels did you get those plans yet?
Not yet - but that is normal around here. I have another item coming
from Philly and it is not here either.
Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
- Pls add your comments at the TOP, SIGN your posts, and snip away
- Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax: (978) 282-1349
- Unsubscribe:bolger-unsubscribe@yahoogroups.com
- Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
Yahoo! Groups Sponsor
Get unlimited calls to
U.S./Canada
------------------------------------------------------------------------------
Yahoo! Groups Links
a.. To visit your group on the web, go to:
http://groups.yahoo.com/group/bolger/
b.. To unsubscribe from this group, send an email to:
bolger-unsubscribe@yahoogroups.com
c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Non-text portions of this message have been removed]
--- Inbolger@yahoogroups.com, "Jason Stancil" <jasonstancil@h...>
wrote:
Of course there is an error in the above - replace the word "stable"
with "unstable"
It should come back up before it gets all filled with water.
i bet you will have a wider range of stabiliy than a lot of slack
bilged, low-sided centerboard production boats!
instead;-)
Wolfard tells about an incident he had when he had the main sheet
cleated and a gust hit. It heeled over and back up so fast he nearly
went overboard. He had two neophytes with him and they just figured
that he did it to scare them, little realizing he had scared himself
a lot more:-)
Another guy was turning a new inverted hull upright by putting it on
a spindle device and raising it up and got a surprise when he and
several friends were rotating it upright. Lots of leverage in that
little keel I guess.
from Philly and it is not here either.
wrote:
> > An overlooked area that can really make a boat stable when************************
> inverted
> > is a large mast and all the standing wire rigging.
Of course there is an error in the above - replace the word "stable"
with "unstable"
> I've thought about this as an 20' 80lbs aluminum keel is kindaprobably the best is to plug most of the holes so water can't get in.
> disheartning....wonder if the foam would make it unstable when up
> right. Ithought of puting a bunch of those foam noodles kidsuse in
> pools.
It should come back up before it gets all filled with water.
i bet you will have a wider range of stabiliy than a lot of slack
bilged, low-sided centerboard production boats!
>for
> The best way to increase the range of stability is
> > with lead ballest down low. MICRO is a prime example:-)
> Hey i'v got the keel batten scarfed and ready to go as well as a
> foam mock up of the keel sheathing. However, i also have a martha
> jane leeboard sitting in my garage :)..........i think i'm going
> the keel mainly because my 200 sqft MJ sail is too much for theHowcum only one leeboard? Sounds like you should have built a MJ
> internally balasted micro/jukebox navigator.
instead;-)
>I have never heard of one actually getting knocked flat. Bernie
> > I have read many accounts about how quickly a MICRO rights itself.
> Go knock that thing down andletme know how it goes!
Wolfard tells about an incident he had when he had the main sheet
cleated and a gust hit. It heeled over and back up so fast he nearly
went overboard. He had two neophytes with him and they just figured
that he did it to scare them, little realizing he had scared himself
a lot more:-)
Another guy was turning a new inverted hull upright by putting it on
a spindle device and raising it up and got a surprise when he and
several friends were rotating it upright. Lots of leverage in that
little keel I guess.
>Not yet - but that is normal around here. I have another item coming
> Jason
> PS.....Nels did you get those plans yet?
from Philly and it is not here either.
> An overlooked area that can really make a boat stable wheninverted
> is a large mast and all the standing wire rigging. Paradox has aenoungh
> short, wood free-standing mast
> I would probably consider filling the mast on your boat with
> foam to seal it. However foam has weight as well and should beused
> with discretion.I've thought about this as an 20' 80lbs aluminum keel is kinda
disheartning....wonder if the foam would make it unstable when up
right. Ithought of puting a bunch of those foam noodles kidsuse in
pools.
The best way to increase the range of stability is
> with lead ballest down low. MICRO is a prime example:-)Hey i'v got the keel batten scarfed and ready to go as well as a
foam mock up of the keel sheathing. However, i also have a martha
jane leeboard sitting in my garage :)..........i think i'm going for
the keel mainly because my 200 sqft MJ sail is too much for the
internally balasted micro/jukebox navigator.
> I have read many accounts about how quickly a MICRO rights itself.Go knock that thing down andletme know how it goes!
Jason
PS.....Nels did you get those plans yet?
--- Inbolger@yahoogroups.com, "Jason Stancil" <jasonstancil@h...>
wrote:
water should be kept as low as possible. Everything lighter than
water should be as high as possible. That way the boat is stable when
upright and unstable when upside down.
In addition I love a boat that keeps out the water. This means the
interior is a large volume of lighter than water floatation. MICRO is
a prime example - doesn't even have a footwell. Paradox it another.
An overlooked area that can really make a boat stable when inverted
is a large mast and all the standing wire rigging. Paradox has a
short, wood free-standing mast.
Bolger also often mentions higher topsides as being a big advantage
to prevent swamping. Read his comments on catboat design in BWAOM
page 39-40. Also the article in WB mag where PCB&F review Jochems
Schooner and St. Valery (Not sure of the name of the second design.)
This article was obviously mostly written by Susanne:-)
I would probably consider filling the mast on your boat with enoungh
foam to seal it. However foam has weight as well and should be used
with discretion. The best way to increase the range of stability is
with lead ballest down low. MICRO is a prime example:-)
Everything about the square boats lend themselves to stability. So
long as they don't get to much weight up high.
I have read many accounts about how quickly a MICRO rights itself.
Cheers, Nels
wrote:
> I've read about everyone of bolger's article and he always saysThis is the simple way I look at it. Everything that is heavier than
> ballast low, bouyancy high and simply "they recover from knockdowns
> in a reassuring fashion" What the heck does that mean.....90
> degrees?
>
> Thanks,
> Jason
water should be kept as low as possible. Everything lighter than
water should be as high as possible. That way the boat is stable when
upright and unstable when upside down.
In addition I love a boat that keeps out the water. This means the
interior is a large volume of lighter than water floatation. MICRO is
a prime example - doesn't even have a footwell. Paradox it another.
An overlooked area that can really make a boat stable when inverted
is a large mast and all the standing wire rigging. Paradox has a
short, wood free-standing mast.
Bolger also often mentions higher topsides as being a big advantage
to prevent swamping. Read his comments on catboat design in BWAOM
page 39-40. Also the article in WB mag where PCB&F review Jochems
Schooner and St. Valery (Not sure of the name of the second design.)
This article was obviously mostly written by Susanne:-)
I would probably consider filling the mast on your boat with enoungh
foam to seal it. However foam has weight as well and should be used
with discretion. The best way to increase the range of stability is
with lead ballest down low. MICRO is a prime example:-)
Everything about the square boats lend themselves to stability. So
long as they don't get to much weight up high.
I have read many accounts about how quickly a MICRO rights itself.
Cheers, Nels
Hey folks,
I've been reading a whole bunch of design stuff trying to figure out
how various boats recover from knockdowns and capsize.
I've read that matt layden's paradox can right from about 150 degrees
(keel boat range).
Jim M's internally ballasted boats are only able to do so from
around 90 degrees.
What gives? Is it paradox's narrow beam with realitively high sides
and the fact it can't ship water when battened down?
Where do the bolger boats fall, like the new MJ, AS19, AS29 and
jessie cooper? At what point do these boats flounder?
I've read about everyone of bolger's article and he always says
ballast low, bouyancy high and simply "they recover from knockdowns
in a reassuring fashion" What the heck does that mean.....90
degrees?
Thanks,
Jason
I've been reading a whole bunch of design stuff trying to figure out
how various boats recover from knockdowns and capsize.
I've read that matt layden's paradox can right from about 150 degrees
(keel boat range).
Jim M's internally ballasted boats are only able to do so from
around 90 degrees.
What gives? Is it paradox's narrow beam with realitively high sides
and the fact it can't ship water when battened down?
Where do the bolger boats fall, like the new MJ, AS19, AS29 and
jessie cooper? At what point do these boats flounder?
I've read about everyone of bolger's article and he always says
ballast low, bouyancy high and simply "they recover from knockdowns
in a reassuring fashion" What the heck does that mean.....90
degrees?
Thanks,
Jason