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Parallax
 
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Default Stevenson Minicup

Got little done this weekend. The nerve of my wife thinking Mothers
Day takes precedence. However, did a little fairing of epoxy on #1
and put one side on #2. Bought a wood plane and shaped the
daggerboard of #1.

Am now leaning toward polytarp sails because I cannot get Tyvek in
great enough width and am not sure of joining pieces.
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Parallax
 
Posts: n/a
Default Stevenson Minicup

(Parallax) wrote in message . com...
(Parallax) wrote in message om...
Got little done this weekend. The nerve of my wife thinking Mothers
Day takes precedence. However, did a little fairing of epoxy on #1
and put one side on #2. Bought a wood plane and shaped the
daggerboard of #1.

Am now leaning toward polytarp sails because I cannot get Tyvek in
great enough width and am not sure of joining pieces.


I keep finding air bubbles under the fibreglas I applied to the edges
so I keep grinding them out and filling them with epoxy. The
fibreglas seems to have been a mistake because the adhesion of the
fibreglas resin to the wood is very poor.
Found that the rudder boxes I made are twisted so I cut them apart and
reglued them between two cement blocks so they cannot twist.
No progress on #2 yesterday.



For Bookie B. You sure do things the hard way. Do ALL calculations
in metric and then convert to english units in the end. This avoids
the craziness of converting ounces to pounds and feet to furlongs etc.
At any rate, for a diameter of 2.375" and wall thickness of 1/16" vs
a diameter of 2" and wall thickness of 1/8", I get a weight ratio of
1.6X. The reccomended numbers result in a total spar weight of about
20 lbs while for my tubing I get 33 lbs.

How significant is this? Now, not all the weight is at the top and to
get an approximation I estimate the weight is centered about 6' up.
At a 30 degree angle of heel, this gives a torque of 98 foot-pounds X
sin(30) = 49 foot-lbs. difference between my tubing and reccomended.
This means my 100 lb son must sit about .5 foot further out to balance
it (I do not multiply by sin(30) cuz I assume he can adjust his body
while leaning out to make his weight vector perpendicular to the
axis.). Being 187 lbs, I would have to sit about 4" further out.
Sorry bout all this stuff, but bein an engineer/physics person, I just
luv calculating stuff.

Thanks fer yer help
  #5   Report Post  
Parallax
 
Posts: n/a
Default Stevenson Minicup

(Parallax) wrote in message . com...
(Parallax) wrote in message . com...
(Parallax) wrote in message om...
Got little done this weekend. The nerve of my wife thinking Mothers
Day takes precedence. However, did a little fairing of epoxy on #1
and put one side on #2. Bought a wood plane and shaped the
daggerboard of #1.

Am now leaning toward polytarp sails because I cannot get Tyvek in
great enough width and am not sure of joining pieces.


I keep finding air bubbles under the fibreglas I applied to the edges
so I keep grinding them out and filling them with epoxy. The
fibreglas seems to have been a mistake because the adhesion of the
fibreglas resin to the wood is very poor.
Found that the rudder boxes I made are twisted so I cut them apart and
reglued them between two cement blocks so they cannot twist.
No progress on #2 yesterday.



For Bookie B. You sure do things the hard way. Do ALL calculations
in metric and then convert to english units in the end. This avoids
the craziness of converting ounces to pounds and feet to furlongs etc.
At any rate, for a diameter of 2.375" and wall thickness of 1/16" vs
a diameter of 2" and wall thickness of 1/8", I get a weight ratio of
1.6X. The reccomended numbers result in a total spar weight of about
20 lbs while for my tubing I get 33 lbs.

How significant is this? Now, not all the weight is at the top and to
get an approximation I estimate the weight is centered about 6' up.
At a 30 degree angle of heel, this gives a torque of 98 foot-pounds X
sin(30) = 49 foot-lbs. difference between my tubing and reccomended.
This means my 100 lb son must sit about .5 foot further out to balance
it (I do not multiply by sin(30) cuz I assume he can adjust his body
while leaning out to make his weight vector perpendicular to the
axis.). Being 187 lbs, I would have to sit about 4" further out.
Sorry bout all this stuff, but bein an engineer/physics person, I just
luv calculating stuff.

Thanks fer yer help



Got the first coat of primer on #1. Got rudder box installed. I like
the barrel bolt idea. 4 coats of poly on rudder and centerboard. Put
mast in place and made shims for it. Assembled rigging and raised it
(without sail). Although theory says the weight of my 1/8" wall
tubing is ok, I am a little worried it is too heavy for my kids. Will
try it and see. Bought a polytarp for a sail.
No progress on #2.


  #6   Report Post  
Parallax
 
Posts: n/a
Default Stevenson Minicup

(Parallax) wrote in message om...
(Parallax) wrote in message . com...
(Parallax) wrote in message . com...
(Parallax) wrote in message om...
Got little done this weekend. The nerve of my wife thinking Mothers
Day takes precedence. However, did a little fairing of epoxy on #1
and put one side on #2. Bought a wood plane and shaped the
daggerboard of #1.

Am now leaning toward polytarp sails because I cannot get Tyvek in
great enough width and am not sure of joining pieces.

I keep finding air bubbles under the fibreglas I applied to the edges
so I keep grinding them out and filling them with epoxy. The
fibreglas seems to have been a mistake because the adhesion of the
fibreglas resin to the wood is very poor.
Found that the rudder boxes I made are twisted so I cut them apart and
reglued them between two cement blocks so they cannot twist.
No progress on #2 yesterday.



For Bookie B. You sure do things the hard way. Do ALL calculations
in metric and then convert to english units in the end. This avoids
the craziness of converting ounces to pounds and feet to furlongs etc.
At any rate, for a diameter of 2.375" and wall thickness of 1/16" vs
a diameter of 2" and wall thickness of 1/8", I get a weight ratio of
1.6X. The reccomended numbers result in a total spar weight of about
20 lbs while for my tubing I get 33 lbs.

How significant is this? Now, not all the weight is at the top and to
get an approximation I estimate the weight is centered about 6' up.
At a 30 degree angle of heel, this gives a torque of 98 foot-pounds X
sin(30) = 49 foot-lbs. difference between my tubing and reccomended.
This means my 100 lb son must sit about .5 foot further out to balance
it (I do not multiply by sin(30) cuz I assume he can adjust his body
while leaning out to make his weight vector perpendicular to the
axis.). Being 187 lbs, I would have to sit about 4" further out.
Sorry bout all this stuff, but bein an engineer/physics person, I just
luv calculating stuff.

Thanks fer yer help



Got the first coat of primer on #1. Got rudder box installed. I like
the barrel bolt idea. 4 coats of poly on rudder and centerboard. Put
mast in place and made shims for it. Assembled rigging and raised it
(without sail). Although theory says the weight of my 1/8" wall
tubing is ok, I am a little worried it is too heavy for my kids. Will
try it and see. Bought a polytarp for a sail.
No progress on #2.



Painted deck with white paint with anti-skid. I will paint over the
white with fluorescent green spray paint. The anti-skid is nice
because it covers a lot of uneveness from my mistakes. Sides will be
a darker green.

Finally managed to obtain visqueen in 12' widths 6 mils thick so will
use it for sails. Installed all rigging and observed how big the sail
will be, IT IS HUGE. Am considering installing a "Topping Lift" to
hold up the aft end of the boom to take some stress off the sail, all
I need is a double pulley on the mast, another cleat on the mast, an
eye on the end of the boom and some more line. Went with 5/16" line
because it is easier ont he hands than 1/4".

I am a little worried about the screws holding the barrel bolts to
ther transom and am considering fastening a larger plywood plate tot
eh transom with the barrel bolts bolted to it from behind.
  #8   Report Post  
Parallax
 
Posts: n/a
Default Stevenson Minicup

(bookieb) wrote in message om...
(Parallax) wrote in message
snip
For Bookie B. You sure do things the hard way. Do ALL calculations
in metric and then convert to english units in the end. This avoids
the craziness of converting ounces to pounds and feet to furlongs etc.

snip

The 55% heavier I came up with is close enough to your 60% as makes no
odds, so I didn't screw up completely (or else we both did :-).

Yep, use Metric units all the time, esp. since even I can divide and
multiply by 10/100/1000 without too many mistakes.

In this group though, I think most readers are from the US,
and are more familiar with Imperial/US units, so that's what I try and
use.

Regards,


US should immediately go metric. I am tired of converting from one
bizarre set of units such as carats/acre-yard into lbs/cubic foot. It
amazes me that ppl put up with this nonsense. Although I am a
Southern redneck american (note capitalization on Southern but not on
american), I strongly urge the adoption of metric. Do all
calculations in MKS system (meters, Kilograms, Coulombs, Amperes,
Joules, etc) and you will never have to convert in the middle of a
calculation. I mean hp?, what is that in a real unit like Watts (1
Watt =1 joule-sec)? The so-called English system makes me want to
express all power units in something like Mt-FN (Megaton-Fortnights).

Back to boats:

The hdwre store reccomended spray painting, BIG MISTAKE. Will return
unused spray cans this afternoon.
I got worried about the little screws holding the rudder assembly to
transom via the barrel bolts and have decided to bolt the barrel bolts
to a larger plywood plate (about 8.5"x9"x3/8") with #8 nuts and bolts
and then glue and screw this plate to the transom.
I did order the lighter weight spars.
When I realized this project was really running up a bill, I decided
to tear up all receipts immediately so I will never know how much
these "Cheap" boats have really cost me.

bookieb.

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