Folks, It might be useful to know a boat's draft under various conditions, so I did some measurements, and wonder if others' estimates are in the same ballpark. Fully-loaded (and I mean fully) for two weeks on saltwater, the keel reached down about 27" (presumably 42" with the centerboard down). My IdaSailor rudder sticks down another foot, for a total draft of 54". Tom Jenkins 2004 M17 Scintilla
Wow- that's really loaded! According to the original drawings, when sitting on the waterline it should draw 19.25". So much for science. jerry ----- Original Message ----- From: "Tom Jenkins" <tjenk@gte.net> To: <montgomery_boats@mailman.xmission.com> Sent: Saturday, July 04, 2009 11:31 AM Subject: M_Boats: draft
Folks, It might be useful to know a boat's draft under various conditions, so I did some measurements, and wonder if others' estimates are in the same ballpark. Fully-loaded (and I mean fully) for two weeks on saltwater, the keel reached down about 27" (presumably 42" with the centerboard down). My IdaSailor rudder sticks down another foot, for a total draft of 54".
Tom Jenkins 2004 M17 Scintilla _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
Remember, there is no privacy on the Internet!
Jerry, I reckon the science is just fine, since Archimedes Principle has made the grade for some 2400 years and counting. Too bad someone with extra time has not run an empirical curve of draft vs. displacement so the rest of us can know when to hike up the skirts, so to speak. Presumably a marine architect can do that easily with mathematics, but that's the hard way for the rest of us. The amazing thing is that the boat moves along tolerably well with all that weight aboard, presumably because the submerged shape is right. I expect acceleration is a bit affected, though, which sucks in a tacking duel. On the other hand, who would race with a motor, 9 gallons of gas, 10 gallons of water, a battery, and 200 lbs of miscellaneous gear on board, not to mention some biomass? Anyway, a hellava boat, I say. Enjoy your 4th! Tom Jenkins M17 Scintilla . ----- Original Message ----- From: "jerry" <jerry@jerrymontgomery.org> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Saturday, July 04, 2009 3:58 PM Subject: Re: M_Boats: draft
Wow- that's really loaded! According to the original drawings, when sitting on the waterline it should draw 19.25". So much for science.
jerry ----- Original Message ----- From: "Tom Jenkins" <tjenk@gte.net> To: <montgomery_boats@mailman.xmission.com> Sent: Saturday, July 04, 2009 11:31 AM Subject: M_Boats: draft
Folks, It might be useful to know a boat's draft under various conditions, so I did some measurements, and wonder if others' estimates are in the same ballpark. Fully-loaded (and I mean fully) for two weeks on saltwater, the keel reached down about 27" (presumably 42" with the centerboard down). My IdaSailor rudder sticks down another foot, for a total draft of 54".
Tom Jenkins 2004 M17 Scintilla _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
Remember, there is no privacy on the Internet!
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
Remember, there is no privacy on the Internet!
I just recently digitized Lyle's 17 drawing as part of the current design project, and according to the 'putor, pounds per inch immersion on the 17 are 312 lbs, this being in salt water. Lyle, like me in pre-computor days, usually calculated only for displacement, PC, and LCB (longitudinal center of bouyancy), which is done by Simpson's law, recently dicussed on this forum. The pounds per inch immersion thing is deceiving because it's valid only at the waterline, and changes rapidly either side of the WL. Like a lot of calculations it mainly is of interest in comparing different shapes. Yes, it's funny how well the 17 sails even tho it's several pounds heavier than the designed displacement , which is why I always tried to build the boat strong using engineering rather than lots of resin. The flush deck 17's were close to weight, which is the major part as to why they were very fast. Good God- it's 6 o'clock, so it's time for me to go terrorize the neighbor lady! jerry ----- Original Message ----- From: "Tom Jenkins" <tjenk@gte.net> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Saturday, July 04, 2009 5:00 PM Subject: Re: M_Boats: draft
Jerry,
I reckon the science is just fine, since Archimedes Principle has made the grade for some 2400 years and counting. Too bad someone with extra time has not run an empirical curve of draft vs. displacement so the rest of us can know when to hike up the skirts, so to speak. Presumably a marine architect can do that easily with mathematics, but that's the hard way for the rest of us. The amazing thing is that the boat moves along tolerably well with all that weight aboard, presumably because the submerged shape is right. I expect acceleration is a bit affected, though, which sucks in a tacking duel. On the other hand, who would race with a motor, 9 gallons of gas, 10 gallons of water, a battery, and 200 lbs of miscellaneous gear on board, not to mention some biomass? Anyway, a hellava boat, I say.
Enjoy your 4th!
Tom Jenkins M17 Scintilla
. ----- Original Message ----- From: "jerry" <jerry@jerrymontgomery.org> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Saturday, July 04, 2009 3:58 PM Subject: Re: M_Boats: draft
Wow- that's really loaded! According to the original drawings, when sitting on the waterline it should draw 19.25". So much for science.
jerry ----- Original Message ----- From: "Tom Jenkins" <tjenk@gte.net> To: <montgomery_boats@mailman.xmission.com> Sent: Saturday, July 04, 2009 11:31 AM Subject: M_Boats: draft
Folks, It might be useful to know a boat's draft under various conditions, so I did some measurements, and wonder if others' estimates are in the same ballpark. Fully-loaded (and I mean fully) for two weeks on saltwater, the keel reached down about 27" (presumably 42" with the centerboard down). My IdaSailor rudder sticks down another foot, for a total draft of 54".
Tom Jenkins 2004 M17 Scintilla _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
Remember, there is no privacy on the Internet!
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
Remember, there is no privacy on the Internet!
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
Remember, there is no privacy on the Internet!
How far in the water does Scintilla sit? How many "wrinkles" down do you still show on the beam? I have 5 with just the basics on board. Joe Seafrog M17 651 ----- Original Message ----- From: "Tom Jenkins" <tjenk@gte.net> To: <montgomery_boats@mailman.xmission.com> Sent: Saturday, July 04, 2009 2:31 PM Subject: M_Boats: draft
Folks, It might be useful to know a boat's draft under various conditions, so I did some measurements, and wonder if others' estimates are in the same ballpark. Fully-loaded (and I mean fully) for two weeks on saltwater, the keel reached down about 27" (presumably 42" with the centerboard down). My IdaSailor rudder sticks down another foot, for a total draft of 54".
Tom Jenkins 2004 M17 Scintilla _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
Remember, there is no privacy on the Internet!
Joe, I too have 5 wrinkles with the "basics" onboard, which in my case include four bronze opening ports, a motor, gas (3 gallons), an electrical system, and the usual fenders and sailing stuff. Laden for the San Juans, water was lapping the 5th wrinkle. I measured again this morning, and I estimate draft to keel unladen of 24.5" and heavily laden 26.5". My conclusion is that the beasts carry cargo pretty well, but that the evolution from racer to mini-cruiser has added a few pounds over the years. Maybe that's why Nascar Chevys don't have air conditioners and cup holders. Montgomerys are shoal draft by any definition, but it is nice to know in advance when to raise the rudder a bit, when to pull up the centerboard, and when to stay in deeper water. As for the "wire guard" idea, that is similar to the silicone tube cap; I like it. Do you put the stop knot (i.e., weight of centerboard) on the wire guard to hold it tight (which requires a small knot that can fit through the cam cleat guide), or do you put the stop knot on the cam cleat and let gravity or friction hold the guide down? Tom Jenkins Scintilla ----- Original Message ----- From: "Joe Murphy" <seagray@embarqmail.com> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Saturday, July 04, 2009 6:10 PM Subject: Re: M_Boats: draft
How far in the water does Scintilla sit? How many "wrinkles" down do you still show on the beam? I have 5 with just the basics on board. Joe Seafrog M17 651 ----- Original Message ----- From: "Tom Jenkins" <tjenk@gte.net> To: <montgomery_boats@mailman.xmission.com> Sent: Saturday, July 04, 2009 2:31 PM Subject: M_Boats: draft
Folks, It might be useful to know a boat's draft under various conditions, so I did some measurements, and wonder if others' estimates are in the same ballpark. Fully-loaded (and I mean fully) for two weeks on saltwater, the keel reached down about 27" (presumably 42" with the centerboard down). My IdaSailor rudder sticks down another foot, for a total draft of 54".
Tom Jenkins 2004 M17 Scintilla _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
Remember, there is no privacy on the Internet!
_______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
Remember, there is no privacy on the Internet!
participants (3)
-
jerry -
Joe Murphy -
Tom Jenkins