Re: [bolger] Re: Isometric of Bolger's 1 Man live-aboard concept.
On Thu, Sep 2, 2010 at 10:05 AM, Bruce Hallman<hallman@...>wrote:One of the benefits I get from modeling a whole bunch of Bolger
boats, is that I sometimes get glimpses into the thought process of
PCB and PB&F
Bruce,
I want you to know how much I look forward to every new model you post. They're fascinating, and I think all of us here appreciate what you are doing.
If the AS-29 was reconfigured where the hull bottom was
to be stepped with a box keel, the biggest thing that would change
would be the amount of ballast.
That's exactly right. A box keel is a submerged body, and even a narrow one displaces a lot of water. Total displacement goes up, even with the main hull floating higher, and more ballast would need to be added. The benefit of the box keel is that that ballast can be inexpensive steel plate which also protects the bottom and is located at the lowest possible point on the boat, lowering the center of gravity.
fred s.
> Yes, I have seen this, and it's what originally got me to thinking about the benefits of a box keel.One of the benefits I get from modeling a whole bunch of Bolger
boats, is that I sometimes get glimpses into the thought process of
PCB and PB&F as he/they worked out trade-offs that go into the
development of their design ideas. To me, the biggest issue that
comes up with box keels is the effect on hull displacement and mass.
Fundamentally, the AS-29 is an extreme case of box keel. And, the
AS-29 needs lots of ballast to make her settle down into her
waterline. If the AS-29 was reconfigured where the hull bottom was
to be stepped with a box keel, the biggest thing that would change
would be the amount of ballast.
On Wed, Sep 1, 2010 at 1:25 PM, prairiedog2332<arvent@...>wrote:Fred,
Have you seen this?
http://groups.yahoo.com/group/bolger_study_plans_only/files/Small%20Moto\
rsailer/
Sort of a scaled down version of the Alaskan Motor Sailor. I think the
box keel creates too much wetted surface to make for good sailing
performance in a hull this short, but is an ideal location for a tiny
diesel engine. This cartoon also points out another disadvantage - lack
of storage space - mainly due to the deadrise in the hull shape.
Anything stored in the box keel - you lose standing headroom there.
NelsYes, I have seen this, and it's what originally got me to thinking about the benefits of a box keel.
If a box keel has the same profile as a salient keel, it has virtually the same wetted area, especially if its on a box boat. The two sides of the box keel are the same as the two sides of the salient keel; the bottom of the keel replaces the bottom of the main hull. The added area comes from curvature and, when following Bolger's pressure equalizing "Sea of Peas" formula, more area toward the bow of the boat, since it would not have the "drag" (cut away forefoot) of the salient keel.
As you note, several problems enter because of the deadrise hull. There is less lateral plane (only 9") because of the deadrise coming down to meet the box keel, and the dead rise hull has nearly the same inefficiency of space utilization as a complex curved boat. It would pound less than a box boat, especially in a chop or at anchor.
The box form provides so much usable space that a much smaller boat becomes functional. There is also more lateral plane, since the box keel extends lower below the main hull. A narrower box keel would also provide more lateral resistance. On Bolger's boat, it's 2.5 feet; on my sketch I kept it at 2 feet. A box keel is a totally submerged body and would act somewhat like a submarine. It would not create the same wave making resistance as a surface body of equal displacement. I wonder if a bulbous bow would be useful.
A center cockpit boat can use a box keel to great advantage. Tankage can be placed under the cockpit. As for placing the engine in the box keel, I like the direction Phil and Susanne have gone with the use of lightweight air cooled diesels placed above the water line with sail outdrives. They used Deutz engines. I think for smaller boats, another German manufacturer, Hatz, makes a nice line of small, lightweight industrial diesels that would work. Their vertical shaft models could be mated to an outboard's lower unit.
The box keel allows for reduction of top hamper and replacement of lead ballast with cheap steel plate that also protects the bottom and lowers the center of gravity. Over the past few years, Phil and Susanne moved away from the full length box keel, only retaining the cutwater portion. Perhaps they discovered some serious problems with it. However, I'm thinking of knocking together a quick and dirty 5/8 scale test boat (10.5' x 4' x 1.2', 700# estimated displacement) just to see how a box keel Micro would act.
fred s.
Fred,
Have you seen this?
http://groups.yahoo.com/group/bolger_study_plans_only/files/Small%20Moto\
rsailer/
Sort of a scaled down version of the Alaskan Motor Sailor. I think the
box keel creates too much wetted surface to make for good sailing
performance in a hull this short, but is an ideal location for a tiny
diesel engine. This cartoon also points out another disadvantage - lack
of storage space - mainly due to the deadrise in the hull shape.
Anything stored in the box keel - you lose standing headroom there.
Nels
Have you seen this?
http://groups.yahoo.com/group/bolger_study_plans_only/files/Small%20Moto\
rsailer/
Sort of a scaled down version of the Alaskan Motor Sailor. I think the
box keel creates too much wetted surface to make for good sailing
performance in a hull this short, but is an ideal location for a tiny
diesel engine. This cartoon also points out another disadvantage - lack
of storage space - mainly due to the deadrise in the hull shape.
Anything stored in the box keel - you lose standing headroom there.
Nels
--- Inbolger@yahoogroups.com, Fred Schumacher <fredschum@...> wrote:
>
> On Tue, Aug 24, 2010 at 3:43 PM, Bruce Hallman hallman@... wrote:
>
> >
> >
> >http://hallman.org/bolger/1man/
> >
> > This has long been one of my favorite Bolger designs, for several
> > reasons. It simply crams in maximum capability into minimum space,
> > with a strong emphasis on function. 19 feet x 7'6" means it is a
> > modest project to tackle, and to keep up and berth.
> >
>
> Bruce,
>
> Was this a design from Phil's pre-box days, before he abandoned
complex
> curves for the possibilities of parsimony? I thought it a good mental
> exercise to take this concept and apply it to the more space
utilization
> efficient Micro and see what comes up.
>
> By replacing Micro's salient keel with a narrow, two foot wide box
keel
> under a 9/8ths scale up of Micro, it's possible to achieve the
functionality
> of the One Man boat in a smaller (17.5 x 6.75 x2) boat that would be
easier
> to build. It would have standing headroom, without the need of a pilot
> house, two berths, galley and head with shower space, room for a
Tortoise on
> top and 7 feet of cockpit, 50 gallons tankage and 75 cubic feet of
storage.
>
> I think whole books could be written about the possibilities of the
Micro
> form factor.
>
> fred s.
>
On Tue, Aug 24, 2010 at 3:43 PM, Bruce Hallman<hallman@...>wrote:http://hallman.org/bolger/1man/
This has long been one of my favorite Bolger designs, for several
reasons. It simply crams in maximum capability into minimum space,
with a strong emphasis on function. 19 feet x 7'6" means it is a
modest project to tackle, and to keep up and berth.
Bruce,
Was this a design from Phil's pre-box days, before he abandoned complex curves for the possibilities of parsimony? I thought it a good mental exercise to take this concept and apply it to the more space utilization efficient Micro and see what comes up.
By replacing Micro's salient keel with a narrow, two foot wide box keel under a 9/8ths scale up of Micro, it's possible to achieve the functionality of the One Man boat in a smaller (17.5 x 6.75 x2) boat that would be easier to build. It would have standing headroom, without the need of a pilot house, two berths, galley and head with shower space, room for a Tortoise on top and 7 feet of cockpit, 50 gallons tankage and 75 cubic feet of storage.
I think whole books could be written about the possibilities of the Micro form factor.
fred s.
> I think you would call the mainsail a gunter rig, yes. It has theI would second guess the choice of the gunter. It's a pretty long and heavy spar for one man if it should have to be handled in a seaway. I think some more usual tabernacle would be a good alternative.
> mainmast installed loose in a free draining box, so the mast can
> rotate to improve the set of the sail.
I guess the differences between the gunter and the Solent lug (as used in the revised Black Skimmer rig) are all in the details.
Bruce,
I enjoy your drawings, and very much appreciate your sharing them with us.
Cheers,
David G
Harbor Woodworks
**********************
I enjoy your drawings, and very much appreciate your sharing them with us.
Cheers,
David G
Harbor Woodworks
**********************
--- Inbolger@yahoogroups.com, Bruce Hallman <hallman@...> wrote:
>
>http://hallman.org/bolger/1man/
>
> This has long been one of my favorite Bolger designs, for several
> reasons. It simply crams in maximum capability into minimum space,
> with a strong emphasis on function. 19 feet x 7'6" means it is a
> modest project to tackle, and to keep up and berth. He said it could
> be strip built, or it could be lapstraked, with the bulk of the sides
> of the hull being made from flat plywood, and the lap straking just at
> the turn of the bilge. Wild guess now, I suspect that there would be
> a 800 pound casting of lead ballast bolted on at the bottom of the
> keel.
>
Here is an excerpt in my files from a mail Bolger sent to the prospective builder a long time ago. No idea where it came from - maybe from you?
"The deckhouse was an afterthought and may be an example of my leading failing as a designer not knowing when to stop. First, I thought she needed something to keep snow off the companionway in winter. Yet a cockpit with this kind of low shelter provides a marvelous place to sit, any time you're anchored or tied up, in fair weather or foul. Then I started thinking how little had to be added to a hatch hood to get stand- ing headroom for cooking and dressing. I could thus avoid the problem you see in designs where the cook is supposed to stand with his head out the hatch. This doesn't work because he can't see what his hands are doing under the deck, and because the dresser and stovetop are too high to use with the hatch closed. The house won't hurt her sailing much; the extra weight and wind resistance aren't important. And it probably doesn't involve a lot more time and money to install than a really good sliding hatch with a spray shroud. Also, for a single-hander, the view from the helm isn't bad, as you can stand up abaft it and look ahead, and see by the sides without much contortion. A word of caution: I doubt it'd be possible to build a house strong enough to be really fit to go to sea, especially if one meant to stay out in a gale, and Lake Huron qualifies as "sea" in terms of this kind of boat. Except for lowering the galley flat and adding a stool for sit- down cooking, the house could be eliminated without changing the cabin."
Even Mr. Bolger's "afterthoughts" are worthy of study, and your isometric shows how it can be done!
Nels
"The deckhouse was an afterthought and may be an example of my leading failing as a designer not knowing when to stop. First, I thought she needed something to keep snow off the companionway in winter. Yet a cockpit with this kind of low shelter provides a marvelous place to sit, any time you're anchored or tied up, in fair weather or foul. Then I started thinking how little had to be added to a hatch hood to get stand- ing headroom for cooking and dressing. I could thus avoid the problem you see in designs where the cook is supposed to stand with his head out the hatch. This doesn't work because he can't see what his hands are doing under the deck, and because the dresser and stovetop are too high to use with the hatch closed. The house won't hurt her sailing much; the extra weight and wind resistance aren't important. And it probably doesn't involve a lot more time and money to install than a really good sliding hatch with a spray shroud. Also, for a single-hander, the view from the helm isn't bad, as you can stand up abaft it and look ahead, and see by the sides without much contortion. A word of caution: I doubt it'd be possible to build a house strong enough to be really fit to go to sea, especially if one meant to stay out in a gale, and Lake Huron qualifies as "sea" in terms of this kind of boat. Except for lowering the galley flat and adding a stool for sit- down cooking, the house could be eliminated without changing the cabin."
Even Mr. Bolger's "afterthoughts" are worthy of study, and your isometric shows how it can be done!
Nels
--- In bolger@yahoogroups.com, Bruce Hallman <hallman@...> wrote:
>
> On Tue, Aug 24, 2010 at 2:23 PM, prairiedog2332 arvent@... wrote:
> >
> >
> >
> > Interesting sail plan. Is that a gunter?
> >
> > Also no place to put a motor as far as I can tell. The doghouse,
> > apparently added as an afterthought is my all time favorite.
> >
> > Nels
>
> I dunno about the doghouse being an afterthought, as while working out
> the 3D model in freeship it seemed well integrated into the full
> design in my opinion. I like how there is a convenient way to stand
> up in the cockpit for visibility and that there is also a comfortable
> place to hang out for shelter from the elements. The Tortoise dingy
> would need to be towed while sailing I think because it blocks the
> view pretty effectively, but how many other 19foot boats can claim to
> be a full time live-aboard, with full standing headroom, a full
> washroom plus on-deck storage of a dingy.
>
> I think you would call the mainsail a gunter rig, yes. It has the
> mainmast installed loose in a free draining box, so the mast can
> rotate to improve the set of the sail.
>
> Also, with the mizzen and boomkin mounted off center port side, there
> would be room for a conventional sailboat swinging outboard mount on
> the starboard side of the transom.
>
> http://www.overtons.com/assets/images/products/large/37391_L1.jpg
>
What a great design, that classic look would fit in anywhere. That long
keel for tracking yet the the w/stern hung rudder and missin(sp?),can't
she her ever getting stuck in irons. Curious, with such a long yard,
does that stay up all the time and the sail is tracked to it for reefing?
I once saw a Tom Thumb , a short steel(prone to pitching) design and
they spent a little extra money and had a outboard motor mount built w/a
1.5 inch diameter screw to raise and lower outboard keeping it close to
transom, owner said he had very little cavitation. Seems like it would
work well here w/the hollow quarters.
Looks like the dingy /hatch give you a place to pull up pants coming out
of the head, maybe take a solar shower in a basin....a real cruiser this one
Bruce Hallman wrote:
keel for tracking yet the the w/stern hung rudder and missin(sp?),can't
she her ever getting stuck in irons. Curious, with such a long yard,
does that stay up all the time and the sail is tracked to it for reefing?
I once saw a Tom Thumb , a short steel(prone to pitching) design and
they spent a little extra money and had a outboard motor mount built w/a
1.5 inch diameter screw to raise and lower outboard keeping it close to
transom, owner said he had very little cavitation. Seems like it would
work well here w/the hollow quarters.
Looks like the dingy /hatch give you a place to pull up pants coming out
of the head, maybe take a solar shower in a basin....a real cruiser this one
Bruce Hallman wrote:
>
>http://hallman.org/bolger/1man/
>
> This has long been one of my favorite Bolger designs, for several
> reasons. It simply crams in maximum capability into minimum space,
> with a strong emphasis on function. 19 feet x 7'6" means it is a
> modest project to tackle, and to keep up and berth. He said it could
> be strip built, or it could be lapstraked, with the bulk of the sides
> of the hull being made from flat plywood, and the lap straking just at
> the turn of the bilge. Wild guess now, I suspect that there would be
> a 800 pound casting of lead ballast bolted on at the bottom of the
> keel.
>
>
On Tue, Aug 24, 2010 at 2:23 PM, prairiedog2332 <arvent@...> wrote:
the 3D model in freeship it seemed well integrated into the full
design in my opinion. I like how there is a convenient way to stand
up in the cockpit for visibility and that there is also a comfortable
place to hang out for shelter from the elements. The Tortoise dingy
would need to be towed while sailing I think because it blocks the
view pretty effectively, but how many other 19foot boats can claim to
be a full time live-aboard, with full standing headroom, a full
washroom plus on-deck storage of a dingy.
I think you would call the mainsail a gunter rig, yes. It has the
mainmast installed loose in a free draining box, so the mast can
rotate to improve the set of the sail.
Also, with the mizzen and boomkin mounted off center port side, there
would be room for a conventional sailboat swinging outboard mount on
the starboard side of the transom.
http://www.overtons.com/assets/images/products/large/37391_L1.jpg
>I dunno about the doghouse being an afterthought, as while working out
>
>
> Interesting sail plan. Is that a gunter?
>
> Also no place to put a motor as far as I can tell. The doghouse,
> apparently added as an afterthought is my all time favorite.
>
> Nels
the 3D model in freeship it seemed well integrated into the full
design in my opinion. I like how there is a convenient way to stand
up in the cockpit for visibility and that there is also a comfortable
place to hang out for shelter from the elements. The Tortoise dingy
would need to be towed while sailing I think because it blocks the
view pretty effectively, but how many other 19foot boats can claim to
be a full time live-aboard, with full standing headroom, a full
washroom plus on-deck storage of a dingy.
I think you would call the mainsail a gunter rig, yes. It has the
mainmast installed loose in a free draining box, so the mast can
rotate to improve the set of the sail.
Also, with the mizzen and boomkin mounted off center port side, there
would be room for a conventional sailboat swinging outboard mount on
the starboard side of the transom.
http://www.overtons.com/assets/images/products/large/37391_L1.jpg
very cool boat
thanks for all your work, they are much appreciated
-----Original Message-----
From: Bruce Hallman <hallman@...>
To: bolger@yahoogroups.com
Sent: Tue, Aug 24, 2010 4:43 pm
Subject: [bolger] Isometric of Bolger's 1 Man live-aboard concept.
From: Bruce Hallman <hallman@...>
To: bolger@yahoogroups.com
Sent: Tue, Aug 24, 2010 4:43 pm
Subject: [bolger] Isometric of Bolger's 1 Man live-aboard concept.
http://hallman.org/bolger/1man/
This has long been one of my favorite Bolger designs, for several
reasons. It simply crams in maximum capability into minimum space,
with a strong emphasis on function. 19 feet x 7'6" means it is a
modest project to tackle, and to keep up and berth. He said it could
be strip built, or it could be lapstraked, with the bulk of the sides
of the hull being made from flat plywood, and the lap straking just at
the turn of the bilge. Wild guess now, I suspect that there would be
a 800 pound casting of lead ballast bolted on at the bottom of the
keel.
This has long been one of my favorite Bolger designs, for several
reasons. It simply crams in maximum capability into minimum space,
with a strong emphasis on function. 19 feet x 7'6" means it is a
modest project to tackle, and to keep up and berth. He said it could
be strip built, or it could be lapstraked, with the bulk of the sides
of the hull being made from flat plywood, and the lap straking just at
the turn of the bilge. Wild guess now, I suspect that there would be
a 800 pound casting of lead ballast bolted on at the bottom of the
keel.
Interesting sail plan. Is that a gunter?
Also no place to put a motor as far as I can tell. The doghouse,
apparently added as an afterthought is my all time favorite.
Nels
Also no place to put a motor as far as I can tell. The doghouse,
apparently added as an afterthought is my all time favorite.
Nels
--- Inbolger@yahoogroups.com, Bruce Hallman <hallman@...> wrote:
>
>http://hallman.org/bolger/1man/
>
> This has long been one of my favorite Bolger designs, for several
> reasons. It simply crams in maximum capability into minimum space,
> with a strong emphasis on function. 19 feet x 7'6" means it is a
> modest project to tackle, and to keep up and berth. He said it could
> be strip built, or it could be lapstraked, with the bulk of the sides
> of the hull being made from flat plywood, and the lap straking just at
> the turn of the bilge. Wild guess now, I suspect that there would be
> a 800 pound casting of lead ballast bolted on at the bottom of the
> keel.
>
http://hallman.org/bolger/1man/
This has long been one of my favorite Bolger designs, for several
reasons. It simply crams in maximum capability into minimum space,
with a strong emphasis on function. 19 feet x 7'6" means it is a
modest project to tackle, and to keep up and berth. He said it could
be strip built, or it could be lapstraked, with the bulk of the sides
of the hull being made from flat plywood, and the lap straking just at
the turn of the bilge. Wild guess now, I suspect that there would be
a 800 pound casting of lead ballast bolted on at the bottom of the
keel.
This has long been one of my favorite Bolger designs, for several
reasons. It simply crams in maximum capability into minimum space,
with a strong emphasis on function. 19 feet x 7'6" means it is a
modest project to tackle, and to keep up and berth. He said it could
be strip built, or it could be lapstraked, with the bulk of the sides
of the hull being made from flat plywood, and the lap straking just at
the turn of the bilge. Wild guess now, I suspect that there would be
a 800 pound casting of lead ballast bolted on at the bottom of the
keel.