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01-11-2012, 18:01
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#1
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Registered User
Join Date: Jan 2011
Location: Salted & Fresh Water
Boat: Dehler Varianta 65
Posts: 190
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Mast height, how to tell?
Hi there,
Can somebody tell me where I can find info on the mast height of some older designs?
I´m looking at boats between 22/27´but I cannot find any specs for them when regarding the mast height (bridge clearence is my concern).
Thanks,
Messias.
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01-11-2012, 18:06
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#2
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Registered User
Join Date: Dec 2007
Posts: 1,076
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Re: Mast height, how to tell?
Depends on the boat I guess. But I think some of the bigger sail lofts tend to have sail dimensions on file for popular models.
Otherwise best to ask here but about a specific model. Somebody will know
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01-11-2012, 18:11
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#3
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Registered User
Join Date: Mar 2011
Posts: 253
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check on sailboatdata.com
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01-11-2012, 18:29
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#4
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Registered User
Join Date: Oct 2010
Location: Kansas City, MO
Boat: In the hunt again, unknown
Posts: 1,331
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Re: Mast height, how to tell?
Quote:
Originally Posted by shamrock
check on sailboatdata.com
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+1
If you still aren't sure, you can still use the old Tan = opp/adj using a piece of line and protractor
Sine, Cosine, Tangent
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01-11-2012, 19:01
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#5
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Moderator Emeritus
Join Date: Sep 2007
Location: Eastern Tennessee
Boat: Research vessel for a university, retired now.
Posts: 10,406
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Re: Mast height, how to tell?
Tape the very end of a measuring tape to the main halyard and hoist away. Then make a close guestimate as to how close it gets to the very top of the mast. You should get it within a few inches. Then measure the distance between the waterline and the point at which the base of the mast meets the deck. Your accuracy should be much less than a foot, which should be close enough. You want to give yourself a few feet of fudge factor when passing under bridges anyway. With power lines you never want to be anywhere close because they can arc many many feet.
__________________
David
Life begins where land ends.
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01-11-2012, 20:28
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#6
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Moderator
Join Date: Feb 2010
Location: La Ciudad de la Misión Didacus de Alcalá en Alta California, Virreinato de Nueva España
Boat: Cal 20
Posts: 20,441
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Re: Mast height, how to tell?
Quote:
Originally Posted by messias
Hi there,
Can somebody tell me where I can find info on the mast height of some older designs?
I´m looking at boats between 22/27´but I cannot find any specs for them when regarding the mast height (bridge clearence is my concern).
Thanks,
Messias.
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This data is not generally listed. But you can scale it from photos or line drawings.
Go to SailboatData.com
If there is a line drawing for the boat in question, download a copy into MicroSoft Paint. A photo can work too if it is taken from directly abeam, slightly ahead or slightly behind and the result will over estimate the mastheight.
Paint shows the x,y coordinate for every pixel in a photo or bitmap.
Place the cursor directly on the bow and stern of the boat and record the values for each.
-Subtract X bow from X stern to get X length. Xb - Xs = Xl
Get the Y values for the masthead and waterline the same way.
-Subtract Y masthead from Y waterline to get Y height. Ym -Yw =Yh
LOA is one of the values listed on SailboatData.com.
Yh * [LOA/Xl] = Mastheight.
This estimate will be good to better than 4", and probably better than 2".
Items atop the mast should be added to this height.
If you want to know about a 'Tall Mast' version but don't have a line drawing, scale the mastheight for the standard boat. Then check the P values for the standard and tall mast versions.
Pdifference = Ptall - Pstandard.
Add Pdifference to the scaled mastheight of the standard boat to get the mastheight of the tallmast version. This assumes that the boom height on the mast was not changed but that is a reasonable assumption to make.
__________________
Num Me Vexo?
For all of your celestial navigation questions: https://navlist.net/
A house is but a boat so poorly built and so firmly run aground no one would think to try and refloat it.
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02-11-2012, 04:08
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#7
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Registered User
Join Date: Jan 2011
Location: Salted & Fresh Water
Boat: Dehler Varianta 65
Posts: 190
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Re: Mast height, how to tell?
Quote:
Originally Posted by Adelie
Paint shows the x,y coordinate for every pixel in a photo or bitmap.
Place the cursor directly on the bow and stern of the boat and record the values for each.
-Subtract X bow from X stern to get X length. Xb - Xs = Xl
Get the Y values for the masthead and waterline the same way.
-Subtract Y masthead from Y waterline to get Y height. Ym -Yw =Yh
LOA is one of the values listed on SailboatData.com.
Yh * [LOA/Xl] = Mastheight.
This estimate will be good to better than 4", and probably better than 2".
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Wow... we have some really dedicated "rocket science" going here
This forum is of precious knowlegde indeed!
Thank you very much for your answers, because i´m not actually asking (yet) for a specific boat, just browsing through some old designs and don´t want to bother you (again, yet ) with too much newbee questions... but i´ll get to it soon!
As soon as I find one that I think it´s "the one", I´ll flood you with questions!
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02-11-2012, 04:57
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#8
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Registered User
Join Date: Dec 2008
Location: St. Georges, Bda
Boat: Rhodes Reliant 41ft
Posts: 4,131
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Re: Mast height, how to tell?
[QUOTE=messias;1074452]Wow... we have some really dedicated "rocket science" going here
This forum is of precious knowlegde indeed!
/QUOTE]
Not all of us Motor under some bridges, and when you hit one, you will know that you are taller than that clearance height. A few help.
__________________
so many projects--so little time !!
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02-11-2012, 05:35
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#9
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Registered User
Join Date: Jun 2008
Location: Tampa, FL
Posts: 5,009
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Re: Mast height, how to tell?
Quote:
Originally Posted by Khagan1227
If you still aren't sure, you can still use the old Tan = opp/adj using a piece of line and protractor
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That was going to be my suggestion--go find a sixth-grader who just finished geometry.
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02-11-2012, 06:01
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#10
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Registered User
Join Date: Apr 2009
Location: Malvernshire, on the sunny side of the hill.
Boat: 50' steel canal and river cruiser
Posts: 1,905
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Re: Mast height, how to tell?
Pythagoras.
Angle of dangle = ..........
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02-11-2012, 06:06
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#11
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Moderator
Join Date: Feb 2010
Location: La Ciudad de la Misión Didacus de Alcalá en Alta California, Virreinato de Nueva España
Boat: Cal 20
Posts: 20,441
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Re: Mast height, how to tell?
Quote:
Originally Posted by messias
Wow... we have some really dedicated "rocket science" going here
This forum is of precious knowlegde indeed!
Thank you very much for your answers, because i´m not actually asking (yet) for a specific boat, just browsing through some old designs and don´t want to bother you (again, yet ) with too much newbee questions... but i´ll get to it soon!
As soon as I find one that I think it´s "the one", I´ll flood you with questions!
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It's not rocket science, it's high school geometry and math plus a bit of experience. I know this because I tried to be a rocket scientist when I was in college and I couldn't hack the math.
__________________
Num Me Vexo?
For all of your celestial navigation questions: https://navlist.net/
A house is but a boat so poorly built and so firmly run aground no one would think to try and refloat it.
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02-11-2012, 06:09
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#12
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Registered User
Join Date: Sep 2009
Location: Hurricane Highway
Boat: O'Day 28
Posts: 3,920
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Re: Mast height, how to tell?
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02-11-2012, 06:36
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#13
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Registered User
Join Date: Jan 2011
Location: Salted & Fresh Water
Boat: Dehler Varianta 65
Posts: 190
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Re: Mast height, how to tell?
I hope it won´t come to that, but hey... if my math is as near good as my present sailing proficiency...
In that matter of "clearance" and starting to appologise for the probable dumb question, but... is there any kind of "pivotting-mast" system in a 22´~28´ boat?
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02-11-2012, 07:06
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#14
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Moderator
Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 18,398
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Re: Mast height, how to tell?
Quote:
Originally Posted by messias
I hope it won´t come to that, but hey... if my math is as near good as my present sailing proficiency...
In that matter of "clearance" and starting to appologise for the probable dumb question, but... is there any kind of "pivotting-mast" system in a 22´~28´ boat?
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Yes, the name you are after is tabernacle, popular with trailer sailer type of yachts.
Pete
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02-11-2012, 07:22
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#15
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Registered User
Join Date: Jan 2011
Location: Salted & Fresh Water
Boat: Dehler Varianta 65
Posts: 190
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Re: Mast height, how to tell?
THANKS Pete!
I´ll look into it right away, because when I was searching for "pivotting", I only had some kind of Race-setup...
And if it´s not too much to ask, is it possible to transform a non-tabernacle into a tabernacle keeping the same mast/sails, or it has to be a fully redesigned one? No races, no best-performances, no nothing... just fooling arround in the bay learning how to sail...
Thanks again!
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