Tod: Thanks for the info. It's great to have people on the list that know such stuff! --Gary Hyde N24 'Sailabration' M15 #235 'Vanilla' On Dec 09, 2004, at 4:25 PM, htmills@bright.net wrote:
Typically, naval architects work with a reference grid that starts where the stem meets the designed waterline and, in a longitudinal direction concludes at either the rudder post or at the end of the designed waterline and that distance, basically the waterline length, is divided into "stations". The station at the bow (where the stem meets the designed waterline) is usually known as the "fore perpendicular" and is numbered "0". The number of stations is pretty arbitrary but the n.a. will select a spacing that is close enough to adequately define the shape of the curves for calculations and construction. In Lyle Hess' day (pre-computerized design), the last station, aft perpendicular, would typically be an even number, e.g. 8 or 10 or 12. This was for convenience for calculating the displacement of the boat, which was usually done with a method known as "Simpson's Rule" or with a mechanical device known as a "planimeter". And, finally, to answer your question, LCB, longitudinal center of buoyancy, is typically a percentage of the waterline, measured from station 0. VCB, vertical center of buoyancy, is typically expressed in actual measurement above a "baseline", often located at the bottom of the keel.
The other planes, besides "stations", are "waterlines", "buttocks", and "diagonals". The first three are all perpendicular to each other in Cartesian fashion while the diagonals are just that, slices through the hull starting along the centerline and angling out towards the bilges of the boat.
picture: "now that I've got all my ducks in a row..." www.bright.net/~htmills/SLD02.jpg
Tod
-----Original Message----- From: montgomery_boats-bounces+htmills=bright.net@mailman.xmission.com [mailto:montgomery_boats- bounces+htmills=bright.net@mailman.xmission.com] On Behalf Of Gary M. Hyde Sent: Thursday, December 09, 2004 4:57 PM To: For and about Montgomery Sailboats Subject: Re: M_Boats: CG and CB for M - 17s
Larry: For those of us ignorant of designations for LCB, etc. could you give us a little explanation? I.e., is LCB 0.55 of the length back from the bow or what? Thanks. --Gary Hyde N24 'Sailabration' M15 #235 'Vanilla'
On Dec 09, 2004, at 12:31 PM, jerry wrote:
Don't know about the center of bouyancy, but the LCB would be right around .55 as per all of Lyle's boats. Jerry jerrymontgomery.org
----- Original Message ----- From: "Frederick M Berthrong" <fthrong@juno.com> To: <montgomery_boats@mailman.xmission.com> Sent: Thursday, December 09, 2004 10:17 AM Subject: M_Boats: CG and CB for M - 17s
Hey All You Salty M-17ers,
Has anyone seen a diagram, drawing, cutaway ... whatever that shows the location of the Centers of Gravity and Buoyancy of the M-17 for various degrees of heel? I searched on the MSOG site and the Montgomery site and didn't see anything.
Thanks!
Fred Berthrong "Dulce" M17 300
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