Re: Boat Offsets and Stitch n Tape
--- In bolger@y..., filmokentucky@a... wrote:
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Westie Farmer had some great tales about Sam's experience in designing a
flash amphibian aircraft, worth looking up at the library ('My Old Boat
Shop'). Good book anyway, no matter what Thomas Firth Jones says..
David Romasco
-----Original Message-----
From: jhkohnen@... [mailto:jhkohnen@...]
Sent: Saturday, March 02, 2002 1:21 PM
To: bolger@yahoogroups.com
Subject: Re: [bolger] Re: Boat Offsets and Stitch n Tape
THE book on developing panel shapes is:
Ship And Aircraft Fairing And Development for Draftsmen and Loftsmen and
Sheet Metal Workers by Sam Rabl
It's available for reasonable prices used (see http://www.abe.com), but
I've also heard that it's been reprinted recently (or maybe it never
went
out of print?).
Yes, that's the same Sam Rabl who wrote Boatbuilding in Your Own Back
Yard.
--
John <jkohnen@...>
http://www.boat-links.com/
Nobody ought to wear a Greek fisherman's hat unless they meet two
conditions:
1. He is a Greek
2. He is a Fisherman <Roy Blount Jr.>
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Bolger rules!!!
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- pls take "personals" off-list, stay on topic, and punctuate
- add your comments at the TOP and SIGN your posts, snip all you like
- To order plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
01930, Fax: (978) 282-1349
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[Non-text portions of this message have been removed]
flash amphibian aircraft, worth looking up at the library ('My Old Boat
Shop'). Good book anyway, no matter what Thomas Firth Jones says..
David Romasco
-----Original Message-----
From: jhkohnen@... [mailto:jhkohnen@...]
Sent: Saturday, March 02, 2002 1:21 PM
To: bolger@yahoogroups.com
Subject: Re: [bolger] Re: Boat Offsets and Stitch n Tape
THE book on developing panel shapes is:
Ship And Aircraft Fairing And Development for Draftsmen and Loftsmen and
Sheet Metal Workers by Sam Rabl
It's available for reasonable prices used (see http://www.abe.com), but
I've also heard that it's been reprinted recently (or maybe it never
went
out of print?).
Yes, that's the same Sam Rabl who wrote Boatbuilding in Your Own Back
Yard.
--
John <jkohnen@...>
http://www.boat-links.com/
Nobody ought to wear a Greek fisherman's hat unless they meet two
conditions:
1. He is a Greek
2. He is a Fisherman <Roy Blount Jr.>
Yahoo! Groups Sponsor
ADVERTISEMENT
<http://rd.yahoo.com/M=215002.1818248.3328688.1261774/D=egroupweb/S=1705
065791:HM/A=847665/R=0/*http:/ads.x10.com/?bHlhaG9vbW9uc3RlcjcuZGF0=1015
095251%3eM=215002.1818248.3328688.1261774/D=egroupweb/S=1705065791:HM/A=
847665/R=1>
<http://us.adserver.yahoo.com/l?M=215002.1818248.3328688.1261774/D=egrou
pmail/S=1705065791:HM/A=847665/rand=298844448>
Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- pls take "personals" off-list, stay on topic, and punctuate
- add your comments at the TOP and SIGN your posts, snip all you like
- To order plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
01930, Fax: (978) 282-1349
- Unsubscribe: bolger-unsubscribe@yahoogroups.com
Your use of Yahoo! Groups is subject to the Yahoo!
<http://docs.yahoo.com/info/terms/> Terms of Service.
[Non-text portions of this message have been removed]
THE book on developing panel shapes is:
Ship And Aircraft Fairing And Development for Draftsmen and Loftsmen and
Sheet Metal Workers by Sam Rabl
It's available for reasonable prices used (see http://www.abe.com), but
I've also heard that it's been reprinted recently (or maybe it never went
out of print?).
Yes, that's the same Sam Rabl who wrote Boatbuilding in Your Own Back Yard.
--
John <jkohnen@...>
http://www.boat-links.com/
Nobody ought to wear a Greek fisherman's hat unless they meet two conditions:
1. He is a Greek
2. He is a Fisherman <Roy Blount Jr.>
Ship And Aircraft Fairing And Development for Draftsmen and Loftsmen and
Sheet Metal Workers by Sam Rabl
It's available for reasonable prices used (see http://www.abe.com), but
I've also heard that it's been reprinted recently (or maybe it never went
out of print?).
Yes, that's the same Sam Rabl who wrote Boatbuilding in Your Own Back Yard.
--
John <jkohnen@...>
http://www.boat-links.com/
Nobody ought to wear a Greek fisherman's hat unless they meet two conditions:
1. He is a Greek
2. He is a Fisherman <Roy Blount Jr.>
Greg,
I've enjoyed your hulls software immensely. It provides such scope
for the imagination. I don't worry about how it works, I just use it
for hours on end pulling and pushing and contemplating the new hull
shapes. It works well for designing decks and structures, wings, and
fuselages too. Thanks a million.
Tom Pannell
Tulls Bay, NC
I've enjoyed your hulls software immensely. It provides such scope
for the imagination. I don't worry about how it works, I just use it
for hours on end pulling and pushing and contemplating the new hull
shapes. It works well for designing decks and structures, wings, and
fuselages too. Thanks a million.
Tom Pannell
Tulls Bay, NC
--- In bolger@y..., "ghartc" <gcarlson@c...> wrote:
> I wrote the "Hulls" program freeware which you can get from
> carlsondesign.com. You design in 3D and it develops the flat panels
> to cut. You can model an existing design, which you know is
> "developable". On a scratch design, my program doesn't restrict you
>
I wrote the "Hulls" program freeware which you can get from
carlsondesign.com. You design in 3D and it develops the flat panels
to cut. You can model an existing design, which you know is
"developable". On a scratch design, my program doesn't restrict you
to conical development (which means each panel lies on a cone or
cylinder), mainly because it doesn't know how. In Hulls, you can
freely bend and twist panels, so they *might* be tortured.
It's a little like bumblees flying - they can't fly, but since they
don't know that, they do anyway. Practically, what happens when you
really bend and twist is that your panel might want to "cup" some
from the straight line segments going around the bulkhead. The
program doesn't know any different. You might see some in short, fat
panels/boats with a lot of torture, though it's generally less
than "manufacturing" (sawing and epoxy-ing) tolerances.
Actually, its a lot more intuitive than it sounds - what looks
pleasing to the eye and streamlined to the water is not going to be
tortured much if at all. So, lots of hulls get built by people who
never heard of donical cevelopment. (Pls send your broadsides to me
directly.)
{That's the difference between engineers or "applied scientists"
(like me) who design to +/-10% and get it built, and scientists who
enjoy rigor. But, I will concede here that I will NOT be volunteering
for the Mars shot that makes it 90% or so of the way back to earth;-}
To output, you can 1.) send the hulls output to a sailmaker who has
one of my plotting machines and would put it on paper for you, 2.)
find a draftsman with a big roll paper plotter and give him the HPGL
or DXF output to plot, 3.) use the handplot.txt and tape meausure to
loft out the panels, or 4.) under the hulls nesting feature, nest the
panels and plot them directly, X by Y, onto the plywood as shown by
the program. The optical method sounds like a lot of extra work (?)
Gregg Carlson
www.carlsondesign.com
carlsondesign.com. You design in 3D and it develops the flat panels
to cut. You can model an existing design, which you know is
"developable". On a scratch design, my program doesn't restrict you
to conical development (which means each panel lies on a cone or
cylinder), mainly because it doesn't know how. In Hulls, you can
freely bend and twist panels, so they *might* be tortured.
It's a little like bumblees flying - they can't fly, but since they
don't know that, they do anyway. Practically, what happens when you
really bend and twist is that your panel might want to "cup" some
from the straight line segments going around the bulkhead. The
program doesn't know any different. You might see some in short, fat
panels/boats with a lot of torture, though it's generally less
than "manufacturing" (sawing and epoxy-ing) tolerances.
Actually, its a lot more intuitive than it sounds - what looks
pleasing to the eye and streamlined to the water is not going to be
tortured much if at all. So, lots of hulls get built by people who
never heard of donical cevelopment. (Pls send your broadsides to me
directly.)
{That's the difference between engineers or "applied scientists"
(like me) who design to +/-10% and get it built, and scientists who
enjoy rigor. But, I will concede here that I will NOT be volunteering
for the Mars shot that makes it 90% or so of the way back to earth;-}
To output, you can 1.) send the hulls output to a sailmaker who has
one of my plotting machines and would put it on paper for you, 2.)
find a draftsman with a big roll paper plotter and give him the HPGL
or DXF output to plot, 3.) use the handplot.txt and tape meausure to
loft out the panels, or 4.) under the hulls nesting feature, nest the
panels and plot them directly, X by Y, onto the plywood as shown by
the program. The optical method sounds like a lot of extra work (?)
Gregg Carlson
www.carlsondesign.com
--- In bolger@y..., "steelcb" <steelcb@y...> wrote:
>Don't know if this is what you have in mind, but I have been using
>the chine designer software I downloaded through the "files" section
>to develop some interesting hull shapes which I modeled in cardboard.
>
>After printing them out, I scanned in those images and inserted
>scanned images into Micrsoft Powerpoint slides. I adjusted these
>inserted images to take up whole page and superimposed a gridwork...
> I recall reading that Jim Michalak uses the method of joiningIt's all based on the concept that the ply doesn't stretch, so the
> triangles.
triangles all stay the same size and shape. Suppose you have a chine
hull drawn with the usual 11 stations (0-10). To lay out the
topsides, you could start with the triangle that has the base at the
chine and rail at station 5, and the peak at the rail on station 6.
The next triangle would have a base at the chine and rail at station
6 and the peak on the chine at station 5. Etc, both ways.
So far as I know, all the fancy software works basically the same
way, except they use a larger number of stations (and/or cleverly
chosen triangles) to cut down the error.
Exercise for the student: What happens when you try this process with
a "non-developable" hull shape? Hint: the trouble begins because the
straight-line length of a triangle side is not the same as the length
measured along the curve of the hull.
Peter
--- In bolger@y..., "rlspell2000" <richard@s...> wrote:
triangles. I.E. A piece of curved plywood can always be reduced to
a grid of ajoined triangles with the length of the legs determined.
If you flatten out the group of triangles, then you know the shape of
the plywood to cut.
In other words, draw a zig-zag line from edge to edge for the full
length of each plywood panel, each of the spaces between the lines
and plywood edge is a triangle. The length of the lines is the same
whether the plywood is bent or flat. You know the length of each
line, so you can layout your cuts.
> Why don't you send Jim Michalak an email?I recall reading that Jim Michalak uses the method of joining
> He developes his panels by
> hand, so he should have the method down.
triangles. I.E. A piece of curved plywood can always be reduced to
a grid of ajoined triangles with the length of the legs determined.
If you flatten out the group of triangles, then you know the shape of
the plywood to cut.
In other words, draw a zig-zag line from edge to edge for the full
length of each plywood panel, each of the spaces between the lines
and plywood edge is a triangle. The length of the lines is the same
whether the plywood is bent or flat. You know the length of each
line, so you can layout your cuts.
Dale, there are free programs like Robert Lainé's "Carene" which
rigorously develop conical surfaces. There's also "Unfold" which does
the same starting from a table of offsets, but it assumes that the
surface is developable. Gregg's "Hull Designer", while much better
than the others in terms of user interface, does not (yet?) perform a
rigorous developability check. You have to use common sense when
working on strongly flared sections of the boats (for example,
modeling the Chebacco hull is practically impossible at the bow).
Of course many commercial hull fairing programs do the plate
development.
The best description of the conical development method I've seen is
in John Teale's "How to design a boat". Also Stephen
Pollard's "boatbuilding with aluminum" has a good description.
For what I know, the most used algorithm is the Kilgore's one, first
described in some publication on fishing boats in the third world
(FAO or some similar organization).
Best, Pippo
rigorously develop conical surfaces. There's also "Unfold" which does
the same starting from a table of offsets, but it assumes that the
surface is developable. Gregg's "Hull Designer", while much better
than the others in terms of user interface, does not (yet?) perform a
rigorous developability check. You have to use common sense when
working on strongly flared sections of the boats (for example,
modeling the Chebacco hull is practically impossible at the bow).
Of course many commercial hull fairing programs do the plate
development.
The best description of the conical development method I've seen is
in John Teale's "How to design a boat". Also Stephen
Pollard's "boatbuilding with aluminum" has a good description.
For what I know, the most used algorithm is the Kilgore's one, first
described in some publication on fishing boats in the third world
(FAO or some similar organization).
Best, Pippo
> Is there a mathematical method to develop the shapes for stitch n
> glue construction of a chined boat from offsets.
Michalak sells a book on designing plywood boats which discusses this.
He also makes reference to a book by Rable which is where he got the
technique. But doesn't Hulls, or whatever it's called, do this?
He also makes reference to a book by Rable which is where he got the
technique. But doesn't Hulls, or whatever it's called, do this?
--- In bolger@y..., "rlspell2000" <richard@s...> wrote:
> Why don't you send Jim Michalak an email? He developes his panels by
> hand, so he should have the method down.
>
> --- In bolger@y..., "imduds" <dalerogers@m...> wrote:
> > Hello, I have a question regarding boat lofting for stitch and
tape.
> > Its slightly off topic for bolger but very relevant in boat
> building.
> >
> > Is there a mathematical method to develop the shapes for stitch n
> > glue construction of a chined boat from offsets.
> >
> > My method until this point is to model the boat from offsets and
> then
> > transfer the shapes from the model. Unfortunately this method is
> > prone to some errors as well as requiring a model to be built. I
> know
> > that there is some CAD software that can do this automatically,
> > however I would prefer a method by hand or using a spreadsheet or
> > tables.
> >
> > Thanks in advance for your help.
> >
> > I am planning a replica 'Egret' Sharpie reduced to 5.4m 18'.
> >
> > PS if anyone is interested I have created a great little
> spreadsheet
> > for converting offsets from ',",18ths to mm and reducing or
> > increasing scale and producing scaled offsets for models.
> >
> > Regards Dale
emmm. Gregg's hulls program, which is what i'm assuming you are
using, will print out a "handplot" file, with the offsets in it for
hand measuring...
using, will print out a "handplot" file, with the offsets in it for
hand measuring...
--- In bolger@y..., "steelcb" <steelcb@y...> wrote:
> Dale,
>
> Don't know if this is what you have in mind, but I have been using
> the chine designer software I downloaded through the "files"
section
> to develop some interesting hull shapes which I modeled in
cardboard.
>
>
> I recently developed an Indian-style canoe that caught my fancy
> enough that I'm transferring it to full size and building it at
about
> the 16 ft length. I am getting the full-size chine shapes by
> printing out the chines on a laser printer at the size the software
> generates(I don't have a plotter which prints full size I've
read).
>
> After printing them out, I scanned in those images and inserted
these
> scanned images into Micrsoft Powerpoint slides. I adjusted these
> inserted images to take up a whole page and superimposed a gridwork
> of squares over this image representing 1 1/2" per square(I assumed
> an 8' length for the image and started halving the distances to get
> this set of grid lines). Using this gridwork, I determined the
> coordinates for set points every foot for a 4' X 8' sheet. I have
now
> transferred these points to a 4' X 8' sheet of thin paneling to cut
a
> pattern. I did this by drawing one foot lines on the paneling and
> transferring the calculated measurements onto these lines.
>
> I also had to transfer the end points of the chines(a little more
> difficult). After these points were all transferred to the
paneling
> sheet, I used a 1" X 1/4" X 9' batten and some small nails to lay
out
> the curved chine shapes. The software prints out shapes that have
> straight lines roughly approximating a curve, but the batten should
> make these chines smoother and hopefully still fit.
>
> I am at the halfway point now, getting ready to prepare the other
> half of the pattern(2nd 4 x 8 sheet). You only have to lay out
half
> of the chines, since the other side of the hull is obtained by
> turning them over.
>
> I haven't finished this process yet, but it looks promising. I
will
> attempt to iron out any mis-matches in the chines while in the
> pattern stage, so when I cut out the luan pieces they will fit
> adequately. Stitch-n-glue likes a sloppy joint anyway, because
more
> of the epoxy gets into a rough joint.
>
> This method is not specifically mathematical, being more
graphically
> derived, but I think it will do what I plan, and has the benefit of
> being free assuming access to a graphic program like
> Powerpoint(except
> for materials). Actually, if you have a few drafting skills, you
> could just take a printout of the chine shapes and draw this grid
> over it with pen & ink. I may have gone overboard with the
> Powerpoint, but I work long nights and it keeps me busy.
>
> Hope this helps.
>
> Tom Pannell
> Tulls Bay, NC
>
>
> > Hello, I have a question regarding boat lofting for stitch and
tape.
> > Its slightly off topic for bolger but very relevant in boat
> building.
> >
> > Is there a mathematical method to develop the shapes for stitch n
> > glue construction of a chined boat from offsets.
> >
> > My method until this point is to model the boat from offsets and
> then
> > transfer the shapes from the model. Unfortunately this method is
> > prone to some errors as well as requiring a model to be built. I
> know
> > that there is some CAD software that can do this automatically,
> > however I would prefer a method by hand or using a spreadsheet or
> > tables.
> >
> > Thanks in advance for your help.
> >
> > I am planning a replica 'Egret' Sharpie reduced to 5.4m 18'.
> >
> > PS if anyone is interested I have created a great little
> spreadsheet
> > for converting offsets from ',",18ths to mm and reducing or
> > increasing scale and producing scaled offsets for models.
> >
> > Regards Dale
Dale,
Don't know if this is what you have in mind, but I have been using
the chine designer software I downloaded through the "files" section
to develop some interesting hull shapes which I modeled in cardboard.
I recently developed an Indian-style canoe that caught my fancy
enough that I'm transferring it to full size and building it at about
the 16 ft length. I am getting the full-size chine shapes by
printing out the chines on a laser printer at the size the software
generates(I don't have a plotter which prints full size I've read).
After printing them out, I scanned in those images and inserted these
scanned images into Micrsoft Powerpoint slides. I adjusted these
inserted images to take up a whole page and superimposed a gridwork
of squares over this image representing 1 1/2" per square(I assumed
an 8' length for the image and started halving the distances to get
this set of grid lines). Using this gridwork, I determined the
coordinates for set points every foot for a 4' X 8' sheet. I have now
transferred these points to a 4' X 8' sheet of thin paneling to cut a
pattern. I did this by drawing one foot lines on the paneling and
transferring the calculated measurements onto these lines.
I also had to transfer the end points of the chines(a little more
difficult). After these points were all transferred to the paneling
sheet, I used a 1" X 1/4" X 9' batten and some small nails to lay out
the curved chine shapes. The software prints out shapes that have
straight lines roughly approximating a curve, but the batten should
make these chines smoother and hopefully still fit.
I am at the halfway point now, getting ready to prepare the other
half of the pattern(2nd 4 x 8 sheet). You only have to lay out half
of the chines, since the other side of the hull is obtained by
turning them over.
I haven't finished this process yet, but it looks promising. I will
attempt to iron out any mis-matches in the chines while in the
pattern stage, so when I cut out the luan pieces they will fit
adequately. Stitch-n-glue likes a sloppy joint anyway, because more
of the epoxy gets into a rough joint.
This method is not specifically mathematical, being more graphically
derived, but I think it will do what I plan, and has the benefit of
being free assuming access to a graphic program like
Powerpoint(except
for materials). Actually, if you have a few drafting skills, you
could just take a printout of the chine shapes and draw this grid
over it with pen & ink. I may have gone overboard with the
Powerpoint, but I work long nights and it keeps me busy.
Hope this helps.
Tom Pannell
Tulls Bay, NC
Don't know if this is what you have in mind, but I have been using
the chine designer software I downloaded through the "files" section
to develop some interesting hull shapes which I modeled in cardboard.
I recently developed an Indian-style canoe that caught my fancy
enough that I'm transferring it to full size and building it at about
the 16 ft length. I am getting the full-size chine shapes by
printing out the chines on a laser printer at the size the software
generates(I don't have a plotter which prints full size I've read).
After printing them out, I scanned in those images and inserted these
scanned images into Micrsoft Powerpoint slides. I adjusted these
inserted images to take up a whole page and superimposed a gridwork
of squares over this image representing 1 1/2" per square(I assumed
an 8' length for the image and started halving the distances to get
this set of grid lines). Using this gridwork, I determined the
coordinates for set points every foot for a 4' X 8' sheet. I have now
transferred these points to a 4' X 8' sheet of thin paneling to cut a
pattern. I did this by drawing one foot lines on the paneling and
transferring the calculated measurements onto these lines.
I also had to transfer the end points of the chines(a little more
difficult). After these points were all transferred to the paneling
sheet, I used a 1" X 1/4" X 9' batten and some small nails to lay out
the curved chine shapes. The software prints out shapes that have
straight lines roughly approximating a curve, but the batten should
make these chines smoother and hopefully still fit.
I am at the halfway point now, getting ready to prepare the other
half of the pattern(2nd 4 x 8 sheet). You only have to lay out half
of the chines, since the other side of the hull is obtained by
turning them over.
I haven't finished this process yet, but it looks promising. I will
attempt to iron out any mis-matches in the chines while in the
pattern stage, so when I cut out the luan pieces they will fit
adequately. Stitch-n-glue likes a sloppy joint anyway, because more
of the epoxy gets into a rough joint.
This method is not specifically mathematical, being more graphically
derived, but I think it will do what I plan, and has the benefit of
being free assuming access to a graphic program like
Powerpoint(except
for materials). Actually, if you have a few drafting skills, you
could just take a printout of the chine shapes and draw this grid
over it with pen & ink. I may have gone overboard with the
Powerpoint, but I work long nights and it keeps me busy.
Hope this helps.
Tom Pannell
Tulls Bay, NC
> Hello, I have a question regarding boat lofting for stitch and tape.building.
> Its slightly off topic for bolger but very relevant in boat
>then
> Is there a mathematical method to develop the shapes for stitch n
> glue construction of a chined boat from offsets.
>
> My method until this point is to model the boat from offsets and
> transfer the shapes from the model. Unfortunately this method isknow
> prone to some errors as well as requiring a model to be built. I
> that there is some CAD software that can do this automatically,spreadsheet
> however I would prefer a method by hand or using a spreadsheet or
> tables.
>
> Thanks in advance for your help.
>
> I am planning a replica 'Egret' Sharpie reduced to 5.4m 18'.
>
> PS if anyone is interested I have created a great little
> for converting offsets from ',",18ths to mm and reducing or
> increasing scale and producing scaled offsets for models.
>
> Regards Dale
Why don't you send Jim Michalak an email? He developes his panels by
hand, so he should have the method down.
hand, so he should have the method down.
--- In bolger@y..., "imduds" <dalerogers@m...> wrote:
> Hello, I have a question regarding boat lofting for stitch and tape.
> Its slightly off topic for bolger but very relevant in boat
building.
>
> Is there a mathematical method to develop the shapes for stitch n
> glue construction of a chined boat from offsets.
>
> My method until this point is to model the boat from offsets and
then
> transfer the shapes from the model. Unfortunately this method is
> prone to some errors as well as requiring a model to be built. I
know
> that there is some CAD software that can do this automatically,
> however I would prefer a method by hand or using a spreadsheet or
> tables.
>
> Thanks in advance for your help.
>
> I am planning a replica 'Egret' Sharpie reduced to 5.4m 18'.
>
> PS if anyone is interested I have created a great little
spreadsheet
> for converting offsets from ',",18ths to mm and reducing or
> increasing scale and producing scaled offsets for models.
>
> Regards Dale
There is no magic method to solve your problem that I know of.
Building a model and lifting the panel shapes and then enlarging them
works but, as you say, there is the probability of error.
If you have the offsets and know that the shape is "developable" in
plywood, then you can loft full size from the offsets.
If you just want to make the boat shorter and retain the beam, you
can reduce the station spacing and proceed as above to loft it.
Willi-nilly changing the size of a boat opens up other problems.
Computer programs exist to generate panel shapes from offsets but
they are not generally foolproof and require some practical knowlege
of the difference between theoretical surfaces and real materials, or
so I am informed by those who do this.
After I had completed the design of my latest boat, I had one of
these gurus to feed it into his software (Autoyacht) which faired the
lines (lofted) and generated the panel layouts. That option is open
if you can find a designer to do this for you.
Building a model and lifting the panel shapes and then enlarging them
works but, as you say, there is the probability of error.
If you have the offsets and know that the shape is "developable" in
plywood, then you can loft full size from the offsets.
If you just want to make the boat shorter and retain the beam, you
can reduce the station spacing and proceed as above to loft it.
Willi-nilly changing the size of a boat opens up other problems.
Computer programs exist to generate panel shapes from offsets but
they are not generally foolproof and require some practical knowlege
of the difference between theoretical surfaces and real materials, or
so I am informed by those who do this.
After I had completed the design of my latest boat, I had one of
these gurus to feed it into his software (Autoyacht) which faired the
lines (lofted) and generated the panel layouts. That option is open
if you can find a designer to do this for you.
--- In bolger@y..., "imduds" <dalerogers@m...> wrote:
> Hello, I have a question regarding boat lofting for stitch and tape.
> Its slightly off topic for bolger but very relevant in boat
building.
>
> Is there a mathematical method to develop the shapes for stitch n
> glue construction of a chined boat from offsets.
>
> My method until this point is to model the boat from offsets and
then
> transfer the shapes from the model. Unfortunately this method is
> prone to some errors as well as requiring a model to be built. I
know
> that there is some CAD software that can do this automatically,
> however I would prefer a method by hand or using a spreadsheet or
> tables.
>
> Thanks in advance for your help.
>
> I am planning a replica 'Egret' Sharpie reduced to 5.4m 18'.
>
> PS if anyone is interested I have created a great little
spreadsheet
> for converting offsets from ',",18ths to mm and reducing or
> increasing scale and producing scaled offsets for models.
>
> Regards Dale
Hello, I have a question regarding boat lofting for stitch and tape.
Its slightly off topic for bolger but very relevant in boat building.
Is there a mathematical method to develop the shapes for stitch n
glue construction of a chined boat from offsets.
My method until this point is to model the boat from offsets and then
transfer the shapes from the model. Unfortunately this method is
prone to some errors as well as requiring a model to be built. I know
that there is some CAD software that can do this automatically,
however I would prefer a method by hand or using a spreadsheet or
tables.
Thanks in advance for your help.
I am planning a replica 'Egret' Sharpie reduced to 5.4m 18'.
PS if anyone is interested I have created a great little spreadsheet
for converting offsets from ',",18ths to mm and reducing or
increasing scale and producing scaled offsets for models.
Regards Dale
Its slightly off topic for bolger but very relevant in boat building.
Is there a mathematical method to develop the shapes for stitch n
glue construction of a chined boat from offsets.
My method until this point is to model the boat from offsets and then
transfer the shapes from the model. Unfortunately this method is
prone to some errors as well as requiring a model to be built. I know
that there is some CAD software that can do this automatically,
however I would prefer a method by hand or using a spreadsheet or
tables.
Thanks in advance for your help.
I am planning a replica 'Egret' Sharpie reduced to 5.4m 18'.
PS if anyone is interested I have created a great little spreadsheet
for converting offsets from ',",18ths to mm and reducing or
increasing scale and producing scaled offsets for models.
Regards Dale