Re: [bolger] Bolger plate on Rudder
Gene--I once had to break up a fight between two eight year old boys who were arguing about whether a Ferrari was faster than a Lamborghini. Obviously, neither knew what they were talking about and, in this case, I'm not at all sure I know what I'm talking about!
In the case of a tip plate, the plate traps the water that is trying to sneak around the end of the rudder. Intuitively, I would guess that this creates more down force on one side than up force on the other.
The tip Plate that Bolger designed for Sweet Pea worked well. I built a rudder with a tip plate for my Marsh Hen and it was a disastor. Mud Hens have a sharply raked stern post and so the rudder pivots at an angle, raising the trailing edge of the tip plate and creating drag. To add to the fun, the rudder is balanced and part of it extends forward under the boat. My new rudder turned out to be bouyant and there was enpugh play in the pitels to allow the balanced part of the rudder to foul the bottom. All of this is a tribute to enthusiasm overwhelming thought, planning, and sober contemplation and has nothing to do with the validity of tip plates on shallow rudders!
This is an area where careful experimentation could resolve some problems. I hope someone else experiments and tells us about it.
John T
In the case of a tip plate, the plate traps the water that is trying to sneak around the end of the rudder. Intuitively, I would guess that this creates more down force on one side than up force on the other.
The tip Plate that Bolger designed for Sweet Pea worked well. I built a rudder with a tip plate for my Marsh Hen and it was a disastor. Mud Hens have a sharply raked stern post and so the rudder pivots at an angle, raising the trailing edge of the tip plate and creating drag. To add to the fun, the rudder is balanced and part of it extends forward under the boat. My new rudder turned out to be bouyant and there was enpugh play in the pitels to allow the balanced part of the rudder to foul the bottom. All of this is a tribute to enthusiasm overwhelming thought, planning, and sober contemplation and has nothing to do with the validity of tip plates on shallow rudders!
This is an area where careful experimentation could resolve some problems. I hope someone else experiments and tells us about it.
John T
----- Original Message -----
From: Gene T.
To:bolger@yahoogroups.com
Sent: Monday, May 16, 2005 1:16 PM
Subject: Re: [bolger] Bolger plate on Rudder
John,
My elementary view of the actions at the end of the
rudder... I see water from the high pressure side
slipping over the end of the rudder to get to the low
pressure side. This results in a swirrling vortex
like on the wing tip of an aircraft. The plate makes
this path very long and the water runs past the boat
before it has a chance to sneak around the rudder.
This results in half of the plate being pushed down
and half being pushed (pulled) up by the pressure
differential. This there should be no tendency for
the plate to cant up or down. It should follow the
water flow along the boat.
Gene T.
--- "John B. Trussell"
<John.Trussell@...> wrote:
> If I understand the purpose of an end plate, it is
> to "trap" the water that eddys off the tip. I am
> guessing, but I think that the water that is trying
> to eddy of the tip exerts some foce on the tip
> plate. The trick to a pivoting tip plate would seem
> to be placing the pivot point where the plate would
> continue to "trap" the eddies while still pivoting
> to remain in a horizontal plane as the rudder kicks
> up. I'm not sure this is possible and if it is, it
> is going to take someone who knows a lot more about
> hydrodynamics than I do to identify the location of
> the pivot point!
>
> John T
> ----- Original Message -----
> From: Gene T.
> To:bolger@yahoogroups.com
> Sent: Saturday, May 14, 2005 8:53 PM
> Subject: Re: [bolger] Bolger plate on Rudder
>
>
> Could the rudder plate pivot at the front so that
> it
> did not act as a brake when kicking up?
>
> Gene T.
>
>
> --- David Davis <sharpie3444@...> wrote:
> > Has anyone tried the Bolger bottom plate on a
> > kick-up rudder?
> >
> > I know the plate would act as a brake when the
> > rudder kicked up. but
> > would one gain speed in light airs due to less
> of a
> > rudder angle?
> >
> > A 3/8 inch steel plate would also act as a "sink
> > weight" to aid in
> > keeping the rudder down.
> >
> > How would the plate be sized in relation to the
> > rudder width and
> > length?
> >
> > Thank You
> >
> > David Davis
> >
> >
> >
> >
> > ------------------------ Yahoo! Groups Sponsor
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> 'Ed,
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> - 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
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> - Open discussion:
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>
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John,
My elementary view of the actions at the end of the
rudder... I see water from the high pressure side
slipping over the end of the rudder to get to the low
pressure side. This results in a swirrling vortex
like on the wing tip of an aircraft. The plate makes
this path very long and the water runs past the boat
before it has a chance to sneak around the rudder.
This results in half of the plate being pushed down
and half being pushed (pulled) up by the pressure
differential. This there should be no tendency for
the plate to cant up or down. It should follow the
water flow along the boat.
Gene T.
--- "John B. Trussell"
<John.Trussell@...> wrote:
My elementary view of the actions at the end of the
rudder... I see water from the high pressure side
slipping over the end of the rudder to get to the low
pressure side. This results in a swirrling vortex
like on the wing tip of an aircraft. The plate makes
this path very long and the water runs past the boat
before it has a chance to sneak around the rudder.
This results in half of the plate being pushed down
and half being pushed (pulled) up by the pressure
differential. This there should be no tendency for
the plate to cant up or down. It should follow the
water flow along the boat.
Gene T.
--- "John B. Trussell"
<John.Trussell@...> wrote:
> If I understand the purpose of an end plate, it ishttp://us.click.yahoo.com/0xaSZB/UOnJAA/Y3ZIAA/_0TolB/TM
> to "trap" the water that eddys off the tip. I am
> guessing, but I think that the water that is trying
> to eddy of the tip exerts some foce on the tip
> plate. The trick to a pivoting tip plate would seem
> to be placing the pivot point where the plate would
> continue to "trap" the eddies while still pivoting
> to remain in a horizontal plane as the rudder kicks
> up. I'm not sure this is possible and if it is, it
> is going to take someone who knows a lot more about
> hydrodynamics than I do to identify the location of
> the pivot point!
>
> John T
> ----- Original Message -----
> From: Gene T.
> To:bolger@yahoogroups.com
> Sent: Saturday, May 14, 2005 8:53 PM
> Subject: Re: [bolger] Bolger plate on Rudder
>
>
> Could the rudder plate pivot at the front so that
> it
> did not act as a brake when kicking up?
>
> Gene T.
>
>
> --- David Davis <sharpie3444@...> wrote:
> > Has anyone tried the Bolger bottom plate on a
> > kick-up rudder?
> >
> > I know the plate would act as a brake when the
> > rudder kicked up. but
> > would one gain speed in light airs due to less
> of a
> > rudder angle?
> >
> > A 3/8 inch steel plate would also act as a "sink
> > weight" to aid in
> > keeping the rudder down.
> >
> > How would the plate be sized in relation to the
> > rudder width and
> > length?
> >
> > Thank You
> >
> > David Davis
> >
> >
> >
> >
> > ------------------------ Yahoo! Groups Sponsor
> > --------------------~-->
> > Has someone you know been affected by illness or
> > disease?
> > Network for Good is THE place to support health
> > awareness efforts!
> >
>
>
> >--------------------------------------------------------------------~->
>
>
> >------------------------------------------------------------------------------
> >
> > 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 Links
> >
> >
> >bolger-unsubscribe@yahoogroups.com
> >
> >
> >
> >
> >
>
>
> 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 Links------------------------------------------------------------------------------
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>
>
>
>
>
>http://us.click.yahoo.com/B9pRWD/3MnJAA/Y3ZIAA/_0TolB/TM
>
> No virus found in this incoming message.
> Checked by AVG Anti-Virus.
> Version: 7.0.308 / Virus Database: 266.11.10 -
> Release Date: 5/13/2005
>
>
> [Non-text portions of this message have been
> removed]
>
>
>
> ------------------------ Yahoo! Groups Sponsor
> --------------------~-->
> In low income neighborhoods, 84% do not own
> computers.
> At Network for Good, help bridge the Digital Divide!
>
>--------------------------------------------------------------------~->
>
>
> 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
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>
>
>
>
>
Bill--I'm with you. The primary use of a rudder with an end plate is for a boat which is supposed to sail in shallow water. Bolger's Sweet Pea with its "slipping keel" is an example. When I built my Sweet Pea, I figured the "slipping keel" was a needless complication, so I installed the keel permanently with a rudder and tips (per PCB's design). With this rig, I could sail in foot deep water and maneuver easily. Bolger's more popular shallow water sailor, the Dovekie, uses a pivoting rudder. When it kicks up, it is still effective, but the helm gets very heavy.
If you are going to be sailing in anything deeper than 2 ft deep water (with, perhaps, the occasional bump), a kick up rudder is the way to go. But if you are going to explore flats and need reliable steering with minimum draft, a rudder with a tip plate is a pretty good choice.
I am currently building a 19 ft sail boat which will operate occassionally in shallow water, and I'm building a kick up rudder. It may not be perfect when I'm in really shallow water, but I won't be in really shallow water that much.
John T
If you are going to be sailing in anything deeper than 2 ft deep water (with, perhaps, the occasional bump), a kick up rudder is the way to go. But if you are going to explore flats and need reliable steering with minimum draft, a rudder with a tip plate is a pretty good choice.
I am currently building a 19 ft sail boat which will operate occassionally in shallow water, and I'm building a kick up rudder. It may not be perfect when I'm in really shallow water, but I won't be in really shallow water that much.
John T
----- Original Message -----
From:wmrpage@...
To:bolger@yahoogroups.com
Sent: Sunday, May 15, 2005 3:13 PM
Subject: Re: [bolger] Bolger plate on Rudder
In a message dated 5/15/05 8:46:54 AM Central Daylight Time,
John.Trussell@...writes:
> If I understand the purpose of an end plate, it is to "trap" the water that
> eddys off the tip.
I'm of the impression is that the function of an end plate is to make a
shallow, fixed rudder as effective as a deeper one. My experience with "tip-up"
rudders is that they get out of the way (mostly) and are undamaged (usually) and
give some residual steering ability (sometimes) when the water gets to shoal
for them. It seems doubtful to me that there are many sailing environments
where trying to combine the virtues of both would warrant the complication of
trying to combine both solutions. The draft of any sailboat's keel, centerboard,
bilge boards or leeboards is generally significantly greater than that of the
rudder(s). If you run aground with a keel boat, you have run aground, and
raising the rudder won''t change anything. If you run aground with the others, it
is certainly useful to get the rudder up as well, but you aren't going to be
sailing anywhere under control until you are in deep enough water to get the
centerboard or its alternatives back down.
Ciao for Niao,
Bill in MN
[Non-text portions of this message have been removed]
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
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[Non-text portions of this message have been removed]
In a message dated 5/15/05 8:46:54 AM Central Daylight Time,
John.Trussell@...writes:
shallow, fixed rudder as effective as a deeper one. My experience with "tip-up"
rudders is that they get out of the way (mostly) and are undamaged (usually) and
give some residual steering ability (sometimes) when the water gets to shoal
for them. It seems doubtful to me that there are many sailing environments
where trying to combine the virtues of both would warrant the complication of
trying to combine both solutions. The draft of any sailboat's keel, centerboard,
bilge boards or leeboards is generally significantly greater than that of the
rudder(s). If you run aground with a keel boat, you have run aground, and
raising the rudder won''t change anything. If you run aground with the others, it
is certainly useful to get the rudder up as well, but you aren't going to be
sailing anywhere under control until you are in deep enough water to get the
centerboard or its alternatives back down.
Ciao for Niao,
Bill in MN
[Non-text portions of this message have been removed]
John.Trussell@...writes:
> If I understand the purpose of an end plate, it is to "trap" the water thatI'm of the impression is that the function of an end plate is to make a
> eddys off the tip.
shallow, fixed rudder as effective as a deeper one. My experience with "tip-up"
rudders is that they get out of the way (mostly) and are undamaged (usually) and
give some residual steering ability (sometimes) when the water gets to shoal
for them. It seems doubtful to me that there are many sailing environments
where trying to combine the virtues of both would warrant the complication of
trying to combine both solutions. The draft of any sailboat's keel, centerboard,
bilge boards or leeboards is generally significantly greater than that of the
rudder(s). If you run aground with a keel boat, you have run aground, and
raising the rudder won''t change anything. If you run aground with the others, it
is certainly useful to get the rudder up as well, but you aren't going to be
sailing anywhere under control until you are in deep enough water to get the
centerboard or its alternatives back down.
Ciao for Niao,
Bill in MN
[Non-text portions of this message have been removed]
If I understand the purpose of an end plate, it is to "trap" the water that eddys off the tip. I am guessing, but I think that the water that is trying to eddy of the tip exerts some foce on the tip plate. The trick to a pivoting tip plate would seem to be placing the pivot point where the plate would continue to "trap" the eddies while still pivoting to remain in a horizontal plane as the rudder kicks up. I'm not sure this is possible and if it is, it is going to take someone who knows a lot more about hydrodynamics than I do to identify the location of the pivot point!
John T
John T
----- Original Message -----
From: Gene T.
To:bolger@yahoogroups.com
Sent: Saturday, May 14, 2005 8:53 PM
Subject: Re: [bolger] Bolger plate on Rudder
Could the rudder plate pivot at the front so that it
did not act as a brake when kicking up?
Gene T.
--- David Davis <sharpie3444@...> wrote:
> Has anyone tried the Bolger bottom plate on a
> kick-up rudder?
>
> I know the plate would act as a brake when the
> rudder kicked up. but
> would one gain speed in light airs due to less of a
> rudder angle?
>
> A 3/8 inch steel plate would also act as a "sink
> weight" to aid in
> keeping the rudder down.
>
> How would the plate be sized in relation to the
> rudder width and
> length?
>
> Thank You
>
> David Davis
>
>
>
>
> ------------------------ Yahoo! Groups Sponsor
> --------------------~-->
> Has someone you know been affected by illness or
> disease?
> Network for Good is THE place to support health
> awareness efforts!
>
http://us.click.yahoo.com/0xaSZB/UOnJAA/Y3ZIAA/_0TolB/TM
>
--------------------------------------------------------------------~->
>
>
> 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 Links
>
>
>bolger-unsubscribe@yahoogroups.com
>
>
>
>
>
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
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[Non-text portions of this message have been removed]
Could the rudder plate pivot at the front so that it
did not act as a brake when kicking up?
Gene T.
--- David Davis <sharpie3444@...> wrote:
did not act as a brake when kicking up?
Gene T.
--- David Davis <sharpie3444@...> wrote:
> Has anyone tried the Bolger bottom plate on ahttp://us.click.yahoo.com/0xaSZB/UOnJAA/Y3ZIAA/_0TolB/TM
> kick-up rudder?
>
> I know the plate would act as a brake when the
> rudder kicked up. but
> would one gain speed in light airs due to less of a
> rudder angle?
>
> A 3/8 inch steel plate would also act as a "sink
> weight" to aid in
> keeping the rudder down.
>
> How would the plate be sized in relation to the
> rudder width and
> length?
>
> Thank You
>
> David Davis
>
>
>
>
> ------------------------ Yahoo! Groups Sponsor
> --------------------~-->
> Has someone you know been affected by illness or
> disease?
> Network for Good is THE place to support health
> awareness efforts!
>
>--------------------------------------------------------------------~->
>
>
> 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 Links
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>bolger-unsubscribe@yahoogroups.com
>
>
>
>
>
>The idea is that you gain speed by needing less total area immersed.I think the biggest reason Bolger likes endplates on rudders is that they
are effective on shoal draft boats.
Angle effect should be about the same. The idea is that you gain speed
by needing less total area immersed. The endplate makes a given area
more efficient, and allows the rudder to be smaller. I may also reduce
foil-end turbulence, but that's an awfully complicated subject and even
tank testing doesn't reflect real-world applications accurately enough
to tell us all we want to know.
--Rob
by needing less total area immersed. The endplate makes a given area
more efficient, and allows the rudder to be smaller. I may also reduce
foil-end turbulence, but that's an awfully complicated subject and even
tank testing doesn't reflect real-world applications accurately enough
to tell us all we want to know.
--Rob
> > I know the plate would act as a brake when the rudder kicked up. but
> > would one gain speed in light airs due to less of a rudder angle?
I believe you'd actually lose speed by adding an end plate. The parasitic
drag would increase due to the added surface area, and the induced drag
would remain the same. (Induced drag is the work you're doing on the water
to generate the yawing moment needed, but you knew that.) Of course, if
you're generating turbulence, then all bets are off as to which is more
effective/less draggy.
Roger
derbyrm@...
http://home.earthlink.net/~derbyrm
drag would increase due to the added surface area, and the induced drag
would remain the same. (Induced drag is the work you're doing on the water
to generate the yawing moment needed, but you knew that.) Of course, if
you're generating turbulence, then all bets are off as to which is more
effective/less draggy.
Roger
derbyrm@...
http://home.earthlink.net/~derbyrm
----- Original Message -----
From: "David Davis" <sharpie3444@...>
<snip>
> I know the plate would act as a brake when the rudder kicked up. but
> would one gain speed in light airs due to less of a rudder angle?
Dave: Putting an end plate on that's fixed on a pivoting rudder blade
might have some unintended consequences. If you're blasting along at 5
yo 6 knots and the rudder kicks up ... you're looking at some severe
strains on the gear. It's the closest you'll ever get to having brakes.
Note the strain isn't just going to be on the rudder & its gear. If you
go from 5 or 6 to 1 or 2 all of a sudden, your mast is going to snap
forward impressively. (BTW, the wings on my pivoting keel are fixed and
when it's all the way up, the wings are at about a 45 degree angle to
the water and the speed is cut at least in half...)
The way to do this, if you want to pursue it, is to have a pivoting
plate. You would have the swinging rudder blade be hollow and run a
control bar or line through the middle to the horizontal plate. Look at
the Insolent 60 drawings (posted on Bolger 2, 3, or 4) to get an idea
of how that would work on a keel. Or if you're a subscriber to
Duckworks Magazine, go to the December 2004 article "Wing Keel
Travails." That shows the prototype Bolger did for me of the I-60 keel
and there's a drawing of how the hollow-in-the-middle concept works.
You need some close toleraces to reduce turbulence and drag, but it
might be worth it. (The I-60 design, as a second generation, is much
better than mine on streamlining)
I'm hoping to experiment with this concept on a leeboard someday,
because it can be so useful in the shallow waters where we sail. It
could also be useful on short daggerboards or dagger leeboards. The
catch here is once the plats or wings are attached, there's no way to
remove the board from the boat, without removing the plate. If you hit
a real shallow patch and have to pull the board all the way up, it
would interfere with the boom in a tack or gybe if the board is too
long.
Gary Blankenship
might have some unintended consequences. If you're blasting along at 5
yo 6 knots and the rudder kicks up ... you're looking at some severe
strains on the gear. It's the closest you'll ever get to having brakes.
Note the strain isn't just going to be on the rudder & its gear. If you
go from 5 or 6 to 1 or 2 all of a sudden, your mast is going to snap
forward impressively. (BTW, the wings on my pivoting keel are fixed and
when it's all the way up, the wings are at about a 45 degree angle to
the water and the speed is cut at least in half...)
The way to do this, if you want to pursue it, is to have a pivoting
plate. You would have the swinging rudder blade be hollow and run a
control bar or line through the middle to the horizontal plate. Look at
the Insolent 60 drawings (posted on Bolger 2, 3, or 4) to get an idea
of how that would work on a keel. Or if you're a subscriber to
Duckworks Magazine, go to the December 2004 article "Wing Keel
Travails." That shows the prototype Bolger did for me of the I-60 keel
and there's a drawing of how the hollow-in-the-middle concept works.
You need some close toleraces to reduce turbulence and drag, but it
might be worth it. (The I-60 design, as a second generation, is much
better than mine on streamlining)
I'm hoping to experiment with this concept on a leeboard someday,
because it can be so useful in the shallow waters where we sail. It
could also be useful on short daggerboards or dagger leeboards. The
catch here is once the plats or wings are attached, there's no way to
remove the board from the boat, without removing the plate. If you hit
a real shallow patch and have to pull the board all the way up, it
would interfere with the boom in a tack or gybe if the board is too
long.
Gary Blankenship
The origin of this thread mentioned reduced drag, from reduced rudder
angle. I suspect that the end plate will itself increase drag more
than it helps via reduced blade angle. In aircraft, it has been
found that the junction of two surfaces causes more drag than one
would expect unless it is well faired. I cannot say if it works the
same in the water. It would probably take fairly sophisticated
testing to prove it either way.
Doug
angle. I suspect that the end plate will itself increase drag more
than it helps via reduced blade angle. In aircraft, it has been
found that the junction of two surfaces causes more drag than one
would expect unless it is well faired. I cannot say if it works the
same in the water. It would probably take fairly sophisticated
testing to prove it either way.
Doug
David Davis wrote:
Bolger designs without kick-up rudders (Reuben's Nymph, June Bug, to
name but two). Since it's easy to swap different rudders and they're not
a huge investment in time or materials to fabricate, it seems to be a
good area in which to experiment with different design ideas.
rudder end plate and then take a more or less educated guess. I doubt
the exact size is critical.
Dan
> Has anyone tried the Bolger bottom plate on a kick-up rudder?No, but I've given serious consideration to using one on a number of
Bolger designs without kick-up rudders (Reuben's Nymph, June Bug, to
name but two). Since it's easy to swap different rudders and they're not
a huge investment in time or materials to fabricate, it seems to be a
good area in which to experiment with different design ideas.
> A 3/8 inch steel plate would also act as a "sink weight" to aid inI can't argue with htat.
> keeping the rudder down.
> How would the plate be sized in relation to the rudder width andNo idea, I'd have a look at other Bolger designs that already used a
> length?
rudder end plate and then take a more or less educated guess. I doubt
the exact size is critical.
Dan
A plate can increase the effectiveness of a rudder, centerboard, bilge
board, leeboard or daggerboard, especially in a good strong breeze. An
increase in effectiveness of centerboard, leeboard or daggerboard won't
noticeably shift the boat's overall center of lateral resistance, because
it's very close to it.
Working against putting plates on centerboards, bilge boards and leeboards
is their need to function when raised part way. Maybe kick-up rudders do
too, but often they can be left all the way down until just before they are
raised right out of the water. Some last-second braking when beaching could
be used to advantage?
So, the plate idea doesn't fly on centerboards, bilge boards or lee boards.
Except for Bolger's articulated plate, which seems a bit too complex to
become widely used.
A plate on a daggerboard could work, if... hmm, I'm working on that one.
- Bill
_____
From:bolger@yahoogroups.com[mailto:bolger@yahoogroups.com] On Behalf Of
Clyde Wisner
Sent: Thursday, May 12, 2005 8:15 AM
To:bolger@yahoogroups.com
Subject: Re: [bolger] Bolger plate on Rudder
I think the purpose of the plate is to change the center of lateral
resistence if necessary, much as the bottom plate on a center board or
wing keel. Clyde
David Davis wrote:
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:
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[Non-text portions of this message have been removed]
board, leeboard or daggerboard, especially in a good strong breeze. An
increase in effectiveness of centerboard, leeboard or daggerboard won't
noticeably shift the boat's overall center of lateral resistance, because
it's very close to it.
Working against putting plates on centerboards, bilge boards and leeboards
is their need to function when raised part way. Maybe kick-up rudders do
too, but often they can be left all the way down until just before they are
raised right out of the water. Some last-second braking when beaching could
be used to advantage?
So, the plate idea doesn't fly on centerboards, bilge boards or lee boards.
Except for Bolger's articulated plate, which seems a bit too complex to
become widely used.
A plate on a daggerboard could work, if... hmm, I'm working on that one.
- Bill
_____
From:bolger@yahoogroups.com[mailto:bolger@yahoogroups.com] On Behalf Of
Clyde Wisner
Sent: Thursday, May 12, 2005 8:15 AM
To:bolger@yahoogroups.com
Subject: Re: [bolger] Bolger plate on Rudder
I think the purpose of the plate is to change the center of lateral
resistence if necessary, much as the bottom plate on a center board or
wing keel. Clyde
David Davis wrote:
> Has anyone tried the Bolger bottom plate on a kick-up rudder?[Non-text portions of this message have been removed]
>
> I know the plate would act as a brake when the rudder kicked up. but
> would one gain speed in light airs due to less of a rudder angle?
>
> A 3/8 inch steel plate would also act as a "sink weight" to aid in
> keeping the rudder down.
>
> How would the plate be sized in relation to the rudder width and
> length?
>
> Thank You
>
> David Davis
>
>
>
>
> 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 Links
>
> * To visit your group on the web, go to:
>http://groups.yahoo.com/group/bolger/
>
> * To unsubscribe from this group, send an email to:
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> Service <http://docs.yahoo.com/info/terms/>.
>
>
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
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<http://docs.yahoo.com/info/terms/> Service.
[Non-text portions of this message have been removed]
I think the purpose of the plate is to change the center of lateral
resistence if necessary, much as the bottom plate on a center board or
wing keel. Clyde
David Davis wrote:
resistence if necessary, much as the bottom plate on a center board or
wing keel. Clyde
David Davis wrote:
> Has anyone tried the Bolger bottom plate on a kick-up rudder?[Non-text portions of this message have been removed]
>
> I know the plate would act as a brake when the rudder kicked up. but
> would one gain speed in light airs due to less of a rudder angle?
>
> A 3/8 inch steel plate would also act as a "sink weight" to aid in
> keeping the rudder down.
>
> How would the plate be sized in relation to the rudder width and
> length?
>
> Thank You
>
> David Davis
>
>
>
>
> 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 Links
>
> * To visit your group on the web, go to:
>http://groups.yahoo.com/group/bolger/
>
> * To unsubscribe from this group, send an email to:
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> Service <http://docs.yahoo.com/info/terms/>.
>
>
--- Inbolger@yahoogroups.com, "John B. Trussell"
Thanks John, I am at that point where I decide to taper the bottom
of the rudder or leave it square so as to experiment with the bottom
plate.
Already cut the wood so this one won't get any longer. Do want to
try the bottom plate and a balanced rudder blade sometime in the
future.
I hadn't thought of a plate on the bottom of the lee board, would
create the braking problem as well. Could make them so as the
bottom plate was easily removible.
<John.Trussell@w...> wrote:
are trying to accomplish.
keels on America Cup boats are advantageous because the 12 meter
formula set some limits on keel depth. Bolger uses end plates on
very shallow rudders. With a kickup rudder, the length of the rudder
blade is not an issue and you can make it as long as you want.
build it how you want, and have fun:>)
Thanks John, I am at that point where I decide to taper the bottom
of the rudder or leave it square so as to experiment with the bottom
plate.
Already cut the wood so this one won't get any longer. Do want to
try the bottom plate and a balanced rudder blade sometime in the
future.
I hadn't thought of a plate on the bottom of the lee board, would
create the braking problem as well. Could make them so as the
bottom plate was easily removible.
<John.Trussell@w...> wrote:
> David--If you really want to get fancy, you could probably rig apivoting plate, but you might want to give some thought to what you
are trying to accomplish.
>airplane wing) has the same effect oas a longer blade. The winged
> An end plate on a rudder (or keel, or even a "winglet" on an
keels on America Cup boats are advantageous because the 12 meter
formula set some limits on keel depth. Bolger uses end plates on
very shallow rudders. With a kickup rudder, the length of the rudder
blade is not an issue and you can make it as long as you want.
>the way we want them and experiment with our ideas. It's your boat,
> But we build our own boats, at least in part, so we can have them
build it how you want, and have fun:>)
>but
> John T
> ----- Original Message -----
> From: David Davis
> To:bolger@yahoogroups.com
> Sent: Wednesday, May 11, 2005 6:46 PM
> Subject: [bolger] Bolger plate on Rudder
>
>
> Has anyone tried the Bolger bottom plate on a kick-up rudder?
>
> I know the plate would act as a brake when the rudder kicked up.
> would one gain speed in light airs due to less of a rudder angle?in
>
> A 3/8 inch steel plate would also act as a "sink weight" to aid
> keeping the rudder down.horses
>
> How would the plate be sized in relation to the rudder width and
> length?
>
> Thank You
>
> David Davis
>
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks,Fred' posts
> - Pls add your comments at the TOP, SIGN your posts, and snipaway
> - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,01930, Fax: (978) 282-1349
> - Unsubscribe:bolger-unsubscribe@yahoogroups.comsubscribe@yahoogroups.com
> - Open discussion: bolger_coffee_lounge-
>-----------
>
>
> -------------------------------------------------------------------
> Yahoo! Groups Linksof Service.
>
> 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
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>-----------
>
>
>
> -------------------------------------------------------------------
>5/10/2005
>
> No virus found in this incoming message.
> Checked by AVG Anti-Virus.
> Version: 7.0.308 / Virus Database: 266.11.8 - Release Date:
>
>
> [Non-text portions of this message have been removed]
David--If you really want to get fancy, you could probably rig a pivoting plate, but you might want to give some thought to what you are trying to accomplish.
An end plate on a rudder (or keel, or even a "winglet" on an airplane wing) has the same effect oas a longer blade. The winged keels on America Cup boats are advantageous because the 12 meter formula set some limits on keel depth. Bolger uses end plates on very shallow rudders. With a kickup rudder, the length of the rudder blade is not an issue and you can make it as long as you want.
But we build our own boats, at least in part, so we can have them the way we want them and experiment with our ideas. It's your boat, build it how you want, and have fun:>)
John T
An end plate on a rudder (or keel, or even a "winglet" on an airplane wing) has the same effect oas a longer blade. The winged keels on America Cup boats are advantageous because the 12 meter formula set some limits on keel depth. Bolger uses end plates on very shallow rudders. With a kickup rudder, the length of the rudder blade is not an issue and you can make it as long as you want.
But we build our own boats, at least in part, so we can have them the way we want them and experiment with our ideas. It's your boat, build it how you want, and have fun:>)
John T
----- Original Message -----
From: David Davis
To:bolger@yahoogroups.com
Sent: Wednesday, May 11, 2005 6:46 PM
Subject: [bolger] Bolger plate on Rudder
Has anyone tried the Bolger bottom plate on a kick-up rudder?
I know the plate would act as a brake when the rudder kicked up. but
would one gain speed in light airs due to less of a rudder angle?
A 3/8 inch steel plate would also act as a "sink weight" to aid in
keeping the rudder down.
How would the plate be sized in relation to the rudder width and
length?
Thank You
David Davis
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
------------------------------------------------------------------------------
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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.
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No virus found in this incoming message.
Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.11.8 - Release Date: 5/10/2005
[Non-text portions of this message have been removed]
Has anyone tried the Bolger bottom plate on a kick-up rudder?
I know the plate would act as a brake when the rudder kicked up. but
would one gain speed in light airs due to less of a rudder angle?
A 3/8 inch steel plate would also act as a "sink weight" to aid in
keeping the rudder down.
How would the plate be sized in relation to the rudder width and
length?
Thank You
David Davis
I know the plate would act as a brake when the rudder kicked up. but
would one gain speed in light airs due to less of a rudder angle?
A 3/8 inch steel plate would also act as a "sink weight" to aid in
keeping the rudder down.
How would the plate be sized in relation to the rudder width and
length?
Thank You
David Davis