Re: [bolger] Re: Aerated Power Boat Bottoms /Sneakeasy
I just heard from someone on the WB forum who's been around Hunter's Child
and confirmed that it does in fact have the aeration system. She's going to
ask Steve Pettingill how it worked for me.
JB
and confirmed that it does in fact have the aeration system. She's going to
ask Steve Pettingill how it worked for me.
JB
----- Original Message -----
From: "tom28571" <harbinger@...>
| I still don't see how they could get enough pressure differential to
| pull air through the hull at that point without introducing drag
| that might be greater than the benefit, but what do I know? The
| Laser tried that on the original models but it never worked as a
| bailer until they put in the extended venturi.
|
|
I believe that Project Amazon, an around-the-world singlehander also
had an aeration scheme. The boat was designed by Eric Sponberg, but
as I recall, the aeration was the owners design. Sponberg's web site
doesn't have details of the design anymore. Maybe someone out there
knows more.
http://www.sponbergyachtdesign.com/SailDesigns.htm
Peter
had an aeration scheme. The boat was designed by Eric Sponberg, but
as I recall, the aeration was the owners design. Sponberg's web site
doesn't have details of the design anymore. Maybe someone out there
knows more.
http://www.sponbergyachtdesign.com/SailDesigns.htm
Peter
This concept is already in production by the US for their Seal
Teams. They have a heavily modified, narrow beam, step chined boat
that can cruise at 70 knots with an ultra smooth ride. Very Slender
Vessel (VSV). The VSV is designed as a wave piercing craft; in lieu
of the standard high speed boat, which produces an extremely
uncomfortable ride over long, high-speed transits in higher sea
states. The VSV is expected to deliver SEAL or other SOF operators to
objective areas who are much more mission capable.
Check out the photo's I put up at Bolger 2.
http://groups.yahoo.com/group/Bolger2/files/Modified%20Sneakeasy/
These boats are very fuel efficient but they give no details of the
power supply's or how they induce the air under the hull be it fans
or venturi effect. They are amazing craft and not to far from the
Wyo/Sneakeasy profile. I also am adding a picture of an air assisted
test bed catamaran. The 'Surface-effect-cat' concept is an air-
assisted catamaran with wave-slicing fine-entry side hulls. Air is
blown into the recesses in the side-hulls. This method of lift
reduces power requirements to about 1/2 that of a conventional
catamaran at cruise speed.
I also took the liberty to use another designers concept boat as a
modified Sneakeasy with reverse bow. It would not be hard to modify
the Sneakeasy the same way. With a LWL at 38' a little air induction
from a cyclone air bilge pump on the drive shaft and it would be a
very sexy missile. The picture is in the same file, a sort of art-
nouveau Sneakeasy. Looks cool anyway.
John
Teams. They have a heavily modified, narrow beam, step chined boat
that can cruise at 70 knots with an ultra smooth ride. Very Slender
Vessel (VSV). The VSV is designed as a wave piercing craft; in lieu
of the standard high speed boat, which produces an extremely
uncomfortable ride over long, high-speed transits in higher sea
states. The VSV is expected to deliver SEAL or other SOF operators to
objective areas who are much more mission capable.
Check out the photo's I put up at Bolger 2.
http://groups.yahoo.com/group/Bolger2/files/Modified%20Sneakeasy/
These boats are very fuel efficient but they give no details of the
power supply's or how they induce the air under the hull be it fans
or venturi effect. They are amazing craft and not to far from the
Wyo/Sneakeasy profile. I also am adding a picture of an air assisted
test bed catamaran. The 'Surface-effect-cat' concept is an air-
assisted catamaran with wave-slicing fine-entry side hulls. Air is
blown into the recesses in the side-hulls. This method of lift
reduces power requirements to about 1/2 that of a conventional
catamaran at cruise speed.
I also took the liberty to use another designers concept boat as a
modified Sneakeasy with reverse bow. It would not be hard to modify
the Sneakeasy the same way. With a LWL at 38' a little air induction
from a cyclone air bilge pump on the drive shaft and it would be a
very sexy missile. The picture is in the same file, a sort of art-
nouveau Sneakeasy. Looks cool anyway.
John
--- In bolger@y..., Chance Curtis <sneakeasy2002@y...> wrote:
>
> The bubbles might have more to do with turbulence. The US Navy did
studies of this affect on fish with scales vs fishskin like sharks.
Fish with scales are faster but fish with skin are quieter. The navy
did develop subs producing bubbles and they were faster, but those
Sonobouys could hear them coming miles away.
> CCG
> dbaldnz wrote:Not strictly a Bolger topic, but an addition to the
current
> Wyo/Sneakeasy bottom discussion.
> During the 1960's, a modern pioneer multihull designer and
> aerodynamics engineer, J.S. Taylor in Australia, built a 23ft ocean
> going sailing trimaran called Maui. It sailed 306 miles in 24 hours
> at sea, remarkable at that time for such a small sailing cruiser.
> The boat had a low deadrise chine hull. The interesting innovation
> however was the double bottom with air space between. Along the
> bottom of the hull, running diagonally from keel to chine, were
> close spaced narrow slits. The air in the bottom space was slightly
> pressurized by a battery driven fan, causing a carpet of bubbles to
> disperse right along the bottom of the hull. I don't know if the
> bubbles acted like a carpet of ball bearings, or whether they
> sheared and lessened resistance. Magazine articles were published
at
> the time, but I have seen nothing like it since. Perhaps others
have
> tried the idea, and I wondered whether it may be applicable to the
> fast powerboats being discussed in this Group.
> DonB
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred'
posts
> - add your comments at the TOP and SIGN your posts and <snip>
away
> - To order plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester,
MA, 01930, Fax: (978) 282-1349
> - Unsubscribe: bolger-unsubscribe@y...
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Service.
>
>
>
> ---------------------------------
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> [Non-text portions of this message have been removed]
The bubbles might have more to do with turbulence. The US Navy did studies of this affect on fish with scales vs fishskin like sharks. Fish with scales are faster but fish with skin are quieter. The navy did develop subs producing bubbles and they were faster, but those Sonobouys could hear them coming miles away.
CCG
dbaldnz wrote:Not strictly a Bolger topic, but an addition to the current
Wyo/Sneakeasy bottom discussion.
During the 1960's, a modern pioneer multihull designer and
aerodynamics engineer, J.S. Taylor in Australia, built a 23ft ocean
going sailing trimaran called Maui. It sailed 306 miles in 24 hours
at sea, remarkable at that time for such a small sailing cruiser.
The boat had a low deadrise chine hull. The interesting innovation
however was the double bottom with air space between. Along the
bottom of the hull, running diagonally from keel to chine, were
close spaced narrow slits. The air in the bottom space was slightly
pressurized by a battery driven fan, causing a carpet of bubbles to
disperse right along the bottom of the hull. I don't know if the
bubbles acted like a carpet of ball bearings, or whether they
sheared and lessened resistance. Magazine articles were published at
the time, but I have seen nothing like it since. Perhaps others have
tried the idea, and I wondered whether it may be applicable to the
fast powerboats being discussed in this Group.
DonB
Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
- add your comments at the TOP and SIGN your posts and <snip> away
- To order 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
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
---------------------------------
Do you Yahoo!?
New DSL Internet Access from SBC & Yahoo!
[Non-text portions of this message have been removed]
CCG
dbaldnz wrote:Not strictly a Bolger topic, but an addition to the current
Wyo/Sneakeasy bottom discussion.
During the 1960's, a modern pioneer multihull designer and
aerodynamics engineer, J.S. Taylor in Australia, built a 23ft ocean
going sailing trimaran called Maui. It sailed 306 miles in 24 hours
at sea, remarkable at that time for such a small sailing cruiser.
The boat had a low deadrise chine hull. The interesting innovation
however was the double bottom with air space between. Along the
bottom of the hull, running diagonally from keel to chine, were
close spaced narrow slits. The air in the bottom space was slightly
pressurized by a battery driven fan, causing a carpet of bubbles to
disperse right along the bottom of the hull. I don't know if the
bubbles acted like a carpet of ball bearings, or whether they
sheared and lessened resistance. Magazine articles were published at
the time, but I have seen nothing like it since. Perhaps others have
tried the idea, and I wondered whether it may be applicable to the
fast powerboats being discussed in this Group.
DonB
Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
- add your comments at the TOP and SIGN your posts and <snip> away
- To order 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
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
---------------------------------
Do you Yahoo!?
New DSL Internet Access from SBC & Yahoo!
[Non-text portions of this message have been removed]
--- In bolger@y..., "John Bell" <jmbell@m...> wrote:
area for that '94 BOC race off the jetty in Charleston. It was
amazing.
I still don't see how they could get enough pressure differential to
pull air through the hull at that point without introducing drag
that might be greater than the benefit, but what do I know? The
Laser tried that on the original models but it never worked as a
bailer until they put in the extended venturi.
Tom
> Tom,It wasn't
>
> It was aft of the keel, on the canoe body underneath the cockpit.
> installed until the last leg of the race from South America to thefinish in
> Charleston, SC. There was precious little coverage at the time,but I
> distinctly remember reading about in on Compuserve Sailing forumso long
> ago.John, I was sailing around with 500 other boats in the starting
>
> JB
>
area for that '94 BOC race off the jetty in Charleston. It was
amazing.
I still don't see how they could get enough pressure differential to
pull air through the hull at that point without introducing drag
that might be greater than the benefit, but what do I know? The
Laser tried that on the original models but it never worked as a
bailer until they put in the extended venturi.
Tom
Tom,
It was aft of the keel, on the canoe body underneath the cockpit. It wasn't
installed until the last leg of the race from South America to the finish in
Charleston, SC. There was precious little coverage at the time, but I
distinctly remember reading about in on Compuserve Sailing forum so long
ago.
JB
It was aft of the keel, on the canoe body underneath the cockpit. It wasn't
installed until the last leg of the race from South America to the finish in
Charleston, SC. There was precious little coverage at the time, but I
distinctly remember reading about in on Compuserve Sailing forum so long
ago.
JB
----- Original Message -----
From: "tom28571" <harbinger@...>
To: <bolger@yahoogroups.com>
Sent: Monday, September 30, 2002 10:41 PM
Subject: [bolger] Re: Aerated Power Boat Bottoms /Sneakeasy
| --- In bolger@y..., "dbaldnz" <oink@p...> wrote:
| > Hi Tom, have you ever heard whether whether there is a speed
| > improvement?
| > DonB
| >
| >
| Don, I have not heard or don't remember any specific data on speed
| improvement from introducing air under a boat without steps. Of
| course, if sufficient air is not let in behind a step, there will be
| a lot of added drag. I will check to see if Marchaj has anything to
| say about that.
|
| John, I did not know about the keel thing on Thursday's Child and
| would be skeptical that any naturally aspirated system could work on
| a keel since it is so far below the water. Also, because of
| increasing pressure, probably none of the air could get past the
| highest openings in the keel if it did work at all.
|
|
|
| Bolger rules!!!
| - no cursing, flaming, trolling, spamming, or flogging dead horses
| - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
| - add your comments at the TOP and SIGN your posts and <snip> away
| - To order 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
|
| Your use of Yahoo! Groups is subject tohttp://docs.yahoo.com/info/terms/
|
|
--- In bolger@y..., "dbaldnz" <oink@p...> wrote:
improvement from introducing air under a boat without steps. Of
course, if sufficient air is not let in behind a step, there will be
a lot of added drag. I will check to see if Marchaj has anything to
say about that.
John, I did not know about the keel thing on Thursday's Child and
would be skeptical that any naturally aspirated system could work on
a keel since it is so far below the water. Also, because of
increasing pressure, probably none of the air could get past the
highest openings in the keel if it did work at all.
> Hi Tom, have you ever heard whether whether there is a speedDon, I have not heard or don't remember any specific data on speed
> improvement?
> DonB
>
>
improvement from introducing air under a boat without steps. Of
course, if sufficient air is not let in behind a step, there will be
a lot of added drag. I will check to see if Marchaj has anything to
say about that.
John, I did not know about the keel thing on Thursday's Child and
would be skeptical that any naturally aspirated system could work on
a keel since it is so far below the water. Also, because of
increasing pressure, probably none of the air could get past the
highest openings in the keel if it did work at all.
During the BOC back in 94?, the Open 60 "Hunter's Child" had a such a system
installed. When the boat reached a certain was supposed to aspirate air
through a series of holes in the bottom aft of the keel, reducing frictional
drag. They got it to work, but I never heard if it actually helped.
JB
installed. When the boat reached a certain was supposed to aspirate air
through a series of holes in the bottom aft of the keel, reducing frictional
drag. They got it to work, but I never heard if it actually helped.
JB
----- Original Message -----
From: "dbaldnz" <oink@...>
To: <bolger@yahoogroups.com>
Sent: Monday, September 30, 2002 7:56 PM
Subject: [bolger] Re: Aerated Power Boat Bottoms /Sneakeasy
| Hi Tom, have you ever heard whether whether there is a speed
| improvement?
| DonB
|
| > Don,
| >
| > Many powerboat designers and experimenters have tried aeriating
| the
| > hull bottom but usually with step bottoms. Some have used air
| > inlets to augment the air that gets in the normal way through the
| > chine area and a few have closed off the chine at the step and
| > supplied all the air from the deck by power fans. Some have
| routed
| > the engine exhaust through the bottom. I have not heard of it
| being
| > done on a sailboat as you speak of though.
| >
| > Tom
|
|
|
| Bolger rules!!!
| - no cursing, flaming, trolling, spamming, or flogging dead horses
| - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
| - add your comments at the TOP and SIGN your posts and <snip> away
| - To order 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
|
| Your use of Yahoo! Groups is subject tohttp://docs.yahoo.com/info/terms/
|
|
Hi Tom, have you ever heard whether whether there is a speed
improvement?
DonB
improvement?
DonB
> Don,the
>
> Many powerboat designers and experimenters have tried aeriating
> hull bottom but usually with step bottoms. Some have used airrouted
> inlets to augment the air that gets in the normal way through the
> chine area and a few have closed off the chine at the step and
> supplied all the air from the deck by power fans. Some have
> the engine exhaust through the bottom. I have not heard of itbeing
> done on a sailboat as you speak of though.
>
> Tom
--- In bolger@y..., "dbaldnz" <oink@p...> wrote:
Many powerboat designers and experimenters have tried aeriating the
hull bottom but usually with step bottoms. Some have used air
inlets to augment the air that gets in the normal way through the
chine area and a few have closed off the chine at the step and
supplied all the air from the deck by power fans. Some have routed
the engine exhaust through the bottom. I have not heard of it being
done on a sailboat as you speak of though.
Tom
> Not strictly a Bolger topic, but an addition to the currentocean
> Wyo/Sneakeasy bottom discussion.
> During the 1960's, a modern pioneer multihull designer and
> aerodynamics engineer, J.S. Taylor in Australia, built a 23ft
> going sailing trimaran called Maui. It sailed 306 miles in 24hours
> at sea, remarkable at that time for such a small sailing cruiser.slightly
> The boat had a low deadrise chine hull. The interesting innovation
> however was the double bottom with air space between. Along the
> bottom of the hull, running diagonally from keel to chine, were
> close spaced narrow slits. The air in the bottom space was
> pressurized by a battery driven fan, causing a carpet of bubblesto
> disperse right along the bottom of the hull. I don't know if theat
> bubbles acted like a carpet of ball bearings, or whether they
> sheared and lessened resistance. Magazine articles were published
> the time, but I have seen nothing like it since. Perhaps othershave
> tried the idea, and I wondered whether it may be applicable to theDon,
> fast powerboats being discussed in this Group.
> DonB
Many powerboat designers and experimenters have tried aeriating the
hull bottom but usually with step bottoms. Some have used air
inlets to augment the air that gets in the normal way through the
chine area and a few have closed off the chine at the step and
supplied all the air from the deck by power fans. Some have routed
the engine exhaust through the bottom. I have not heard of it being
done on a sailboat as you speak of though.
Tom
Not strictly a Bolger topic, but an addition to the current
Wyo/Sneakeasy bottom discussion.
During the 1960's, a modern pioneer multihull designer and
aerodynamics engineer, J.S. Taylor in Australia, built a 23ft ocean
going sailing trimaran called Maui. It sailed 306 miles in 24 hours
at sea, remarkable at that time for such a small sailing cruiser.
The boat had a low deadrise chine hull. The interesting innovation
however was the double bottom with air space between. Along the
bottom of the hull, running diagonally from keel to chine, were
close spaced narrow slits. The air in the bottom space was slightly
pressurized by a battery driven fan, causing a carpet of bubbles to
disperse right along the bottom of the hull. I don't know if the
bubbles acted like a carpet of ball bearings, or whether they
sheared and lessened resistance. Magazine articles were published at
the time, but I have seen nothing like it since. Perhaps others have
tried the idea, and I wondered whether it may be applicable to the
fast powerboats being discussed in this Group.
DonB
Wyo/Sneakeasy bottom discussion.
During the 1960's, a modern pioneer multihull designer and
aerodynamics engineer, J.S. Taylor in Australia, built a 23ft ocean
going sailing trimaran called Maui. It sailed 306 miles in 24 hours
at sea, remarkable at that time for such a small sailing cruiser.
The boat had a low deadrise chine hull. The interesting innovation
however was the double bottom with air space between. Along the
bottom of the hull, running diagonally from keel to chine, were
close spaced narrow slits. The air in the bottom space was slightly
pressurized by a battery driven fan, causing a carpet of bubbles to
disperse right along the bottom of the hull. I don't know if the
bubbles acted like a carpet of ball bearings, or whether they
sheared and lessened resistance. Magazine articles were published at
the time, but I have seen nothing like it since. Perhaps others have
tried the idea, and I wondered whether it may be applicable to the
fast powerboats being discussed in this Group.
DonB