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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. |
Stevenson Minicup
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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 |
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. |
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. |
Stevenson Minicup
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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. |
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, bookieb. OOOps, my metric tirade swhut down my brain. I mean 1 watt =1Joule/sec and I meant Mt/FN. |
Stevenson Minicup
(Parallax) wrote in message . com...
(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, bookieb. OOOps, my metric tirade swhut down my brain. I mean 1 watt =1Joule/sec and I meant Mt/FN. Made my first sail. I am glad I used visqueen because the first attempt was botched. Yielded a serviceable "back-up" sail but I will make another. |
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