Re: A nine inch mast
> An interesting comment. I would have thought the board feet andepoxy
> would be about the same.The economic advantage was that the width of the desinged staves (on
>
> The disadvantage of the Parker Hex is that an elaborate jig is
> required to get all the staves in alignment, while the bird's mouth
> is (supposed to be!) self_aligning. The bird's mouth concept can be
> adapted to any useful number of staves.
Bolgers design) were impossible to find in France and a good
portionwound up being either routed out or planed away.e or hard to
make and just winds up being part of the spar table for the glue...
The jig is neither elaborate or hard to make and just winds up being
part of the spar table for the glue...Took about fiftten minutes to
make them.
Bob
St Thomas
> I instead used ReuelAn interesting comment. I would have thought the board feet and epoxy
> Parker's hex building method which was a lot more economical than
> Bolger's.
would be about the same.
The disadvantage of the Parker Hex is that an elaborate jig is
required to get all the staves in alignment, while the bird's mouth
is (supposed to be!) self_aligning. The bird's mouth concept can be
adapted to any useful number of staves.
I had just looked over Parker's book before reading your post, and I
must say that I don't understand his scarfing jig at all. (I'm not a
craftsman.)
On the issue of which Bolger boats require hollow masts, I would say
that it would probably be more precise to ask which Bolger plans show
hollow masts. This is one area where builders seem to feel free to
improvise. Note the comment about Sweet Chariot in Different
Boats: " .. the prototype was given much heavier masts than those I
designed for her; a 10-inch-diameter aluminum mainmast in place of a
7 1/2 inch oblong wooden one."
Peter
Peter
For Loose Moose 2 I did something I always advise others not to do
and went another direction than on the plans...I instead used Reull
Parkers hex building method which was a lot more economical than
Bolgers. The construction took a week and a half...two days prepping
and scarfing the pieces one day of total madness in glueing up the
mast and a relaxing week of final shaping and varnishing. Total cost
of the mast was $300 for the wood ( douglas fir) $56. for the epoxy
and another $200 for the stainless top cap,side panels and ballast
bucket(for want of a better term)and somewhere in the region of $65
for the lead ballast.
But talk to Gougon as they have some really neat ideas for spars!
Bob
St Thomas USVI
and went another direction than on the plans...I instead used Reull
Parkers hex building method which was a lot more economical than
Bolgers. The construction took a week and a half...two days prepping
and scarfing the pieces one day of total madness in glueing up the
mast and a relaxing week of final shaping and varnishing. Total cost
of the mast was $300 for the wood ( douglas fir) $56. for the epoxy
and another $200 for the stainless top cap,side panels and ballast
bucket(for want of a better term)and somewhere in the region of $65
for the lead ballast.
But talk to Gougon as they have some really neat ideas for spars!
Bob
St Thomas USVI
--- In bolger@y..., "porcupinefysh" <porcupine@d...> wrote:
some unknown degree of chance. Exactly what degree you cannot really
know until the moment of truth. Further, many other things can cause
failure beyond bad materials. [workmanship, design, connections,
luck, ...] Bad materials may not be the "weak link".
Where I work, [building bridges] when we face big time exposure to
risk of failure, we do a proof test.
IWO, if the mast absolutely must support XXX lbs of bending load: put
the mast in a mockup, pull on it with a calibrated hydraulic jack to
150% of the required strength. If it doesn't fail, you can feel
pretty safe. If it fails, only the wood is damaged, no loss of life.
Or, sometimes we use a gravity "proof load", we lift a large concrete
block of known weight.
I think that EVEN IF you use gold plated materials; when life and
death are at stake AND you want assurances of safety, you should do a
test. If you used cheap materials, and you pass the test, you won a
gamble.
> The costs related to the potentialSpending money on quality materials protects you from failure only by
> sinking of the vessel, not to mention injury or death to the crew,
> are simply too great.
some unknown degree of chance. Exactly what degree you cannot really
know until the moment of truth. Further, many other things can cause
failure beyond bad materials. [workmanship, design, connections,
luck, ...] Bad materials may not be the "weak link".
Where I work, [building bridges] when we face big time exposure to
risk of failure, we do a proof test.
IWO, if the mast absolutely must support XXX lbs of bending load: put
the mast in a mockup, pull on it with a calibrated hydraulic jack to
150% of the required strength. If it doesn't fail, you can feel
pretty safe. If it fails, only the wood is damaged, no loss of life.
Or, sometimes we use a gravity "proof load", we lift a large concrete
block of known weight.
I think that EVEN IF you use gold plated materials; when life and
death are at stake AND you want assurances of safety, you should do a
test. If you used cheap materials, and you pass the test, you won a
gamble.
Porky --
All good points. Sometimes "good enough" is the same as "exactly right"
I suppose the point of my sketching it this:
1)I've always found it easier to finish something than to start in
the first place. To that end I favor of underestimating the
cost/difficultly so as to remove or at least reduce issues of inertia
2) I've had some surprising luck finding clear wood at H.D. or other
lumber yards. Never in 32' lengths, but I did fin a 28' 2"x12" that
was perfectly clear, and I find 2x4s on a pretty regular basis. Even
lumber from Condon's is going to require scarfing. I'm not sure that
I couldn't find enough clear lumber at H.D. to do the job. In any
event, it's fun to think about what *might* be done with materials
that are readily available.
3) It's going to be a while until I see the real specs (whatever they
may be) Other than a couple of Gulls Sue and I are going to build
later this Spring, these sketches are going to be the best I can do
for a while.
YIBB,
David
415 W.46th Street
New York, New York 10036
http://www.crumblingempire.com
(212) 247-0296
All good points. Sometimes "good enough" is the same as "exactly right"
I suppose the point of my sketching it this:
1)I've always found it easier to finish something than to start in
the first place. To that end I favor of underestimating the
cost/difficultly so as to remove or at least reduce issues of inertia
2) I've had some surprising luck finding clear wood at H.D. or other
lumber yards. Never in 32' lengths, but I did fin a 28' 2"x12" that
was perfectly clear, and I find 2x4s on a pretty regular basis. Even
lumber from Condon's is going to require scarfing. I'm not sure that
I couldn't find enough clear lumber at H.D. to do the job. In any
event, it's fun to think about what *might* be done with materials
that are readily available.
3) It's going to be a while until I see the real specs (whatever they
may be) Other than a couple of Gulls Sue and I are going to build
later this Spring, these sketches are going to be the best I can do
for a while.
YIBB,
David
>I think that you'll find the specs for the mast a la Bolger are goingC.E.P.
>to be a bit more demanding than you are hoping. In a previous post
>that was eaten by the cyberspacedawgs, I mentioned the mast for the
>Loose Moose 2. This spar is 25 cm (10") diameter by 10.83 M (about
>34') high. It is to be built round and hollow from clear spruce with
>2.5 cm thick walls. These specs are mainly to allow the use of a
>tabernacle without a heavy winch to raise the mast. Still, the mast
>needs a 183.7 Kg (404 lbs.) counterweight on the low end to function.
>The mast has to be light.
>
>I'm not sure I understand why you're hoping to built your masts "bread
>and butter" fashion of lumberyard wood. Although the technique
>appears simple and cheap, it still requires scarfs (12:1, usually)
>unless you can locate clear boards the full length of the spar, which
>is unlikely. And that "clear wood" spec is not a ostentatious option.
>These are two largely unsupported sticks carrying 400-500 square feet
>of sail on a heavily ballasted 8000 lbs boat. Although a few tight
>small knots can be accepted, any substantial splint, split, large
>knot or other inperfection will serve as a point of failure. You do
>not want an 8"x30' chunk of wood crashing down on your deck (or your
>head). Saving a few dollars (okay, a few hundred dollars) on cheap,
>weak wood would be false economy. The costs related to the potential
>sinking of the vessel, not to mention injury or death to the crew,
>are simply too great.
>
>The AS-29 needs a hollow 6" diameter mast of clear Douglas fir, BTW.
>It is shaped from a square section built of 1.75" thick staves,
>
>--- In bolger@y..., David Ryan <david@c...> wrote:
>> FBBB --
>>
>> Err, make that:
>>
>>http://www.crumblingempire.com/insolent/9inchbrute.gif
>>
>> YIBB,
>>
>> David
>>
>> C.E.P.
>> 415 W.46th Street
>> New York, New York 10036
>>http://www.crumblingempire.com
>> (212) 247-0296
>
>
>
>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 tohttp://docs.yahoo.com/info/terms/
415 W.46th Street
New York, New York 10036
http://www.crumblingempire.com
(212) 247-0296
David,
I think that you'll find the specs for the mast a la Bolger are going
to be a bit more demanding than you are hoping. In a previous post
that was eaten by the cyberspacedawgs, I mentioned the mast for the
Loose Moose 2. This spar is 25 cm (10") diameter by 10.83 M (about
34') high. It is to be built round and hollow from clear spruce with
2.5 cm thick walls. These specs are mainly to allow the use of a
tabernacle without a heavy winch to raise the mast. Still, the mast
needs a 183.7 Kg (404 lbs.) counterweight on the low end to function.
The mast has to be light.
I'm not sure I understand why you're hoping to built your masts "bread
and butter" fashion of lumberyard wood. Although the technique
appears simple and cheap, it still requires scarfs (12:1, usually)
unless you can locate clear boards the full length of the spar, which
is unlikely. And that "clear wood" spec is not a ostentatious option.
These are two largely unsupported sticks carrying 400-500 square feet
of sail on a heavily ballasted 8000 lbs boat. Although a few tight
small knots can be accepted, any substantial splint, split, large
knot or other inperfection will serve as a point of failure. You do
not want an 8"x30' chunk of wood crashing down on your deck (or your
head). Saving a few dollars (okay, a few hundred dollars) on cheap,
weak wood would be false economy. The costs related to the potential
sinking of the vessel, not to mention injury or death to the crew,
are simply too great.
The AS-29 needs a hollow 6" diameter mast of clear Douglas fir, BTW.
It is shaped from a square section built of 1.75" thick staves,
I think that you'll find the specs for the mast a la Bolger are going
to be a bit more demanding than you are hoping. In a previous post
that was eaten by the cyberspacedawgs, I mentioned the mast for the
Loose Moose 2. This spar is 25 cm (10") diameter by 10.83 M (about
34') high. It is to be built round and hollow from clear spruce with
2.5 cm thick walls. These specs are mainly to allow the use of a
tabernacle without a heavy winch to raise the mast. Still, the mast
needs a 183.7 Kg (404 lbs.) counterweight on the low end to function.
The mast has to be light.
I'm not sure I understand why you're hoping to built your masts "bread
and butter" fashion of lumberyard wood. Although the technique
appears simple and cheap, it still requires scarfs (12:1, usually)
unless you can locate clear boards the full length of the spar, which
is unlikely. And that "clear wood" spec is not a ostentatious option.
These are two largely unsupported sticks carrying 400-500 square feet
of sail on a heavily ballasted 8000 lbs boat. Although a few tight
small knots can be accepted, any substantial splint, split, large
knot or other inperfection will serve as a point of failure. You do
not want an 8"x30' chunk of wood crashing down on your deck (or your
head). Saving a few dollars (okay, a few hundred dollars) on cheap,
weak wood would be false economy. The costs related to the potential
sinking of the vessel, not to mention injury or death to the crew,
are simply too great.
The AS-29 needs a hollow 6" diameter mast of clear Douglas fir, BTW.
It is shaped from a square section built of 1.75" thick staves,
--- In bolger@y..., David Ryan <david@c...> wrote:
> FBBB --
>
> Err, make that:
>
>http://www.crumblingempire.com/insolent/9inchbrute.gif
>
> YIBB,
>
> David
>
> C.E.P.
> 415 W.46th Street
> New York, New York 10036
>http://www.crumblingempire.com
> (212) 247-0296
FBBB --
Err, make that:
http://www.crumblingempire.com/insolent/9inchbrute.gif
YIBB,
David
C.E.P.
415 W.46th Street
New York, New York 10036
http://www.crumblingempire.com
(212) 247-0296
Err, make that:
http://www.crumblingempire.com/insolent/9inchbrute.gif
YIBB,
David
C.E.P.
415 W.46th Street
New York, New York 10036
http://www.crumblingempire.com
(212) 247-0296
FBBB --
Springing from Peter V's comment regarding heeling and inertia, I
sketched up an idea for a 9" diameter mast that could be glued up
from Home Depot 2x10s.
http://www.crumblingempire.com/insolent/9inchbrute.html
2x8s are $.77/foot, so let's allow $1/foot for 2x10, or $192/mast not
counting any loss for scarfing. A comparable bird's mouth mast
requires staves 1.8" x 3.6", tantalizingly close to a dressed 2x4. Oh
well.
YIBB,
David
C.E.P.
415 W.46th Street
New York, New York 10036
http://www.crumblingempire.com
(212) 247-0296
Springing from Peter V's comment regarding heeling and inertia, I
sketched up an idea for a 9" diameter mast that could be glued up
from Home Depot 2x10s.
http://www.crumblingempire.com/insolent/9inchbrute.html
2x8s are $.77/foot, so let's allow $1/foot for 2x10, or $192/mast not
counting any loss for scarfing. A comparable bird's mouth mast
requires staves 1.8" x 3.6", tantalizingly close to a dressed 2x4. Oh
well.
YIBB,
David
C.E.P.
415 W.46th Street
New York, New York 10036
http://www.crumblingempire.com
(212) 247-0296