I tracked down a calculator at: https://www.triangle-calculator.com/?what=rt&a=b%3D262+A%3D1&submit=Solve Input: b=255 A=1 This is the mast height 255 inches (21’ 3”) and rake angle of 1 degree The result is 4.451 inches. So if you float the boat on her lines and hoist a light line via main halyard with a weight tied to the bottom end (I use a crescent wrench), one degree of rake should leave the line about 4.5 inches from the after side of the mast near the base. If your mast is a different length, go to the website and plug in your numbers. Les
Yep...in a previous thread Dave and/or Jerry said that level fore and aft is when cockpit seats are level fore and aft, so if you're doing this on a trailer or stands etc. just get the cockpit seats level fore/aft, that's what I did. I used the main halyard, with a pound or two weighting the bottom, and accounting for the slight clearance between halyard and mast at top (subtract that from your measurement from base of mast to hanging halyard). I think it would be really hard to do this on a boat in the water, since you have to be on it and move around a bit to measure this even if it's totally glassy and windless... cheers, John On 5/3/19 2:23 PM, Les Schuldt wrote:
I tracked down a calculator at: https://www.triangle-calculator.com/?what=rt&a=b%3D262+A%3D1&submit=Solve
Input: b=255 A=1
This is the mast height 255 inches (21’ 3”) and rake angle of 1 degree
The result is 4.451 inches. So if you float the boat on her lines and hoist a light line via main halyard with a weight tied to the bottom end (I use a crescent wrench), one degree of rake should leave the line about 4.5 inches from the after side of the mast near the base. If your mast is a different length, go to the website and plug in your numbers.
Les
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com
John, Good points, all. Well almost all... As the sheave and halyard shackle will start the light line about 1/2-3/4” farther aft at the top, you’ll actually want to ADD that small factor to your measurements at the bottom. Les
On May 3, 2019, at 2:40 PM, John Schinnerer <john@eco-living.net> wrote:
Yep...in a previous thread Dave and/or Jerry said that level fore and aft is when cockpit seats are level fore and aft, so if you're doing this on a trailer or stands etc. just get the cockpit seats level fore/aft, that's what I did.
I used the main halyard, with a pound or two weighting the bottom, and accounting for the slight clearance between halyard and mast at top (subtract that from your measurement from base of mast to hanging halyard).
I think it would be really hard to do this on a boat in the water, since you have to be on it and move around a bit to measure this even if it's totally glassy and windless...
cheers, John
On 5/3/19 2:23 PM, Les Schuldt wrote: I tracked down a calculator at: https://www.triangle-calculator.com/?what=rt&a=b%3D262+A%3D1&submit=Solve Input: b=255 A=1 This is the mast height 255 inches (21’ 3”) and rake angle of 1 degree The result is 4.451 inches. So if you float the boat on her lines and hoist a light line via main halyard with a weight tied to the bottom end (I use a crescent wrench), one degree of rake should leave the line about 4.5 inches from the after side of the mast near the base. If your mast is a different length, go to the website and plug in your numbers. Les
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com
Yep, what Les said...I got that one backwards. Add the gap from mast to halyard at sheave. Meaning if you want 6" of rake, and gap is 1/2", rake mast aft until you have 6 1/2" from mast to hanging halyard. oops, John On 5/3/19 2:46 PM, Les Schuldt wrote:
John, Good points, all. Well almost all...
As the sheave and halyard shackle will start the light line about 1/2-3/4” farther aft at the top, you’ll actually want to ADD that small factor to your measurements at the bottom.
Les
On May 3, 2019, at 2:40 PM, John Schinnerer <john@eco-living.net> wrote:
Yep...in a previous thread Dave and/or Jerry said that level fore and aft is when cockpit seats are level fore and aft, so if you're doing this on a trailer or stands etc. just get the cockpit seats level fore/aft, that's what I did.
I used the main halyard, with a pound or two weighting the bottom, and accounting for the slight clearance between halyard and mast at top (subtract that from your measurement from base of mast to hanging halyard).
I think it would be really hard to do this on a boat in the water, since you have to be on it and move around a bit to measure this even if it's totally glassy and windless...
cheers, John
On 5/3/19 2:23 PM, Les Schuldt wrote: I tracked down a calculator at: https://www.triangle-calculator.com/?what=rt&a=b%3D262+A%3D1&submit=Solve Input: b=255 A=1 This is the mast height 255 inches (21’ 3”) and rake angle of 1 degree The result is 4.451 inches. So if you float the boat on her lines and hoist a light line via main halyard with a weight tied to the bottom end (I use a crescent wrench), one degree of rake should leave the line about 4.5 inches from the after side of the mast near the base. If your mast is a different length, go to the website and plug in your numbers. Les
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com
Exact rake will depend on sails: age, cut, and your preferences. Start with 6" and play. Get Jerry to come and sail with you for perfect tuning! :: Dave Scobie :: M6'8" #650 :: SV SWALLOW - sv-swallow.com :: former owner M17 #375 SWEET PEA - m17-375.com :: former owner M15 #288 SCRED - www.freewebs.com/m15-named-scred/ On Fri, May 3, 2019, 3:26 PM John Schinnerer <john@eco-living.net> wrote:
Yep, what Les said...I got that one backwards. Add the gap from mast to halyard at sheave. Meaning if you want 6" of rake, and gap is 1/2", rake mast aft until you have 6 1/2" from mast to hanging halyard.
oops, John
On 5/3/19 2:46 PM, Les Schuldt wrote:
John, Good points, all. Well almost all...
As the sheave and halyard shackle will start the light line about 1/2-3/4” farther aft at the top, you’ll actually want to ADD that small factor to your measurements at the bottom.
Les
On May 3, 2019, at 2:40 PM, John Schinnerer <john@eco-living.net> wrote:
Yep...in a previous thread Dave and/or Jerry said that level fore and aft is when cockpit seats are level fore and aft, so if you're doing this on a trailer or stands etc. just get the cockpit seats level fore/aft, that's what I did.
I used the main halyard, with a pound or two weighting the bottom, and accounting for the slight clearance between halyard and mast at top (subtract that from your measurement from base of mast to hanging halyard).
I think it would be really hard to do this on a boat in the water, since you have to be on it and move around a bit to measure this even if it's totally glassy and windless...
cheers, John
On 5/3/19 2:23 PM, Les Schuldt wrote: I tracked down a calculator at:
https://www.triangle-calculator.com/?what=rt&a=b%3D262+A%3D1&submit=Solve
Input: b=255 A=1 This is the mast height 255 inches (21’ 3”) and rake angle of 1 degree The result is 4.451 inches. So if you float the boat on her lines and hoist a light line via main halyard with a weight tied to the bottom end (I use a crescent wrench), one degree of rake should leave the line about 4.5 inches from the after side of the mast near the base. If your mast is a different length, go to the website and plug in your numbers. Les
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com
I'm guessing that 4.5" isn't enough, and 9" mightn't not be too much. I go by feel; load up the helm a bit any time the boat is heeled. You want to put that long, effective rudder to work reducing leeway. -----Original Message----- From: Les Schuldt Sent: Friday, May 03, 2019 2:23 PM To: montgomery_boats@mailman.xmission.com Subject: M_Boats: M17 Mast Rake I tracked down a calculator at: https://www.triangle-calculator.com/?what=rt&a=b%3D262+A%3D1&submit=Solve Input: b=255 A=1 This is the mast height 255 inches (21’ 3”) and rake angle of 1 degree The result is 4.451 inches. So if you float the boat on her lines and hoist a light line via main halyard with a weight tied to the bottom end (I use a crescent wrench), one degree of rake should leave the line about 4.5 inches from the after side of the mast near the base. If your mast is a different length, go to the website and plug in your numbers. Les
participants (4)
-
Dave Scobie -
jerry＠jerrymontgomery.org -
John Schinnerer -
Les Schuldt