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
Frederick M Berthrong wrote:
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
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
I think with a boat as small as the M 17 you could experimentally find the restoring moment by hauling the boat on to her beam ends by a block and line attached to the masthead crane with the boat tied to a dock and a large spring fishing scale terminating this line at the base of the mast. I was able to pull my Nonsuch 26 over to about 60 deg this way and she is 9000 lbs diaplacement. Dick
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
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
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
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
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
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
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
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
I had mine delivered to my driveway, by a really generous and kind previous owner. I think that he really loved the boat, and just wanted to spend as much time before he passed her on. Probably also wanted to make sure that she was going to a suitable home, as well. And we were and are already good friends! I was aboard when he first sailed aboard her, at a local lake when a scary lightning storm came up (do you remember that, Mike?). I love the stories of the long distances traveled for acquiring these lovely boats! ---Thomas Howe O --------(\ ---------- ~ (\ ~ ~ ~ ~ ~ ~ ~ ~ (\ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
I had my 17 trucked from Libby, Montana to Sandusky, Ohio. Would've driven out to pick it up except I wasn't sure my tow vehicle at the time was up to the trip. She had come to Libby from Port Angeles, Washington and to Port Angeles from San Diego. Tod M17 #408 BuscaBrisas
Ok here's my tale. I picked up my M17 in Vancouver, B.C. so I actually had to leave the country to get her (it was about a 1000 mile round trip). The M23 came from Minnesota. The seller agreed to meet me in Billings, Montana which was only about a 2200 mile round trip(as opposed to the 4000 it would have been otherwise). The tough part about that trip was crossing the northern Rockies in December with my new boat! Mark Dvorscak M23 #74 Faith
. . . some epic trip in Alaska or something prior to your owner her? ----- Original Message ----- From: htmills@bright.net To: 'For and about Montgomery Sailboats' Sent: Wednesday, December 15, 2004 10:55 PM Subject: How Far? I had my 17 trucked from Libby, Montana to Sandusky, Ohio. Would've driven out to pick it up except I wasn't sure my tow vehicle at the time was up to the trip. She had come to Libby from Port Angeles, Washington and to Port Angeles from San Diego. Tod M17 #408 BuscaBrisas
That was on her own bottom, though Port Angeles, WA to Bella Coola, BC and back. A seven week cruise. Rod's story is in the MSOG newsletter archives. Part 1: http://msog.org/mon/mon4-4/mon4-4-1.htm http://msog.org/mon/mon4-4/mon4-4-3.htm http://msog.org/mon/mon4-4/mon4-4-6.htm http://msog.org/mon/mon4-4/mon4-4-8.htm Part 2: http://msog.org/mon/mon5-1/mon5-1-1.htm http://msog.org/mon/mon5-1/mon5-1-2.htm http://msog.org/mon/mon5-1/mon5-1-4.htm I understand that this past summer Rod sailed his present boat, a Yankee Dolphin 24, around Vancouver Island. Tod M17 #408 BuscaBrisas "celebrating the year full of Montgomery Cruises"
Outstanding, Tod, thanks! --Craig ----- Original Message ----- From: htmills@bright.net To: 'For and about Montgomery Sailboats' Sent: Saturday, December 18, 2004 1:25 PM Subject: didn't busca make . . . That was on her own bottom, though Port Angeles, WA to Bella Coola, BC and back. A seven week cruise. Rod's story is in the MSOG newsletter archives. Part 1: http://msog.org/mon/mon4-4/mon4-4-1.htm http://msog.org/mon/mon4-4/mon4-4-3.htm http://msog.org/mon/mon4-4/mon4-4-6.htm http://msog.org/mon/mon4-4/mon4-4-8.htm Part 2: http://msog.org/mon/mon5-1/mon5-1-1.htm http://msog.org/mon/mon5-1/mon5-1-2.htm http://msog.org/mon/mon5-1/mon5-1-4.htm I understand that this past summer Rod sailed his present boat, a Yankee Dolphin 24, around Vancouver Island. Tod M17 #408 BuscaBrisas "celebrating the year full of Montgomery Cruises" _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
The .55 is 55 % of the waterline length back from the fwd end of the WL. I incorrectly said I don't know about the "center of bouyancy" but what I meant was the CG; the center of gravity. The LCB is the longitudinal center of bouyance; fore-and-aft, in other words. Most well-designed sailboats have an LCB in the area of .55, which means 5% of the WL length aft of the center of the WL. I also approach this number in my racing canoes/kayaks and it seems to work out OK. OK? Jerry jerrymontgomery.org ----- Original Message ----- From: "Gary M. Hyde" <gmhyde1@mac.com> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Thursday, December 09, 2004 1:56 PM 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
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
participants (8)
-
Craig F. Honshell -
Frederick M Berthrong -
Gary M. Hyde -
htmills＠bright.net -
jerry -
Richard Lane -
Roberta Dvorscak -
Thomas Howe