The wooden wedges in the partners lock the mast into position inside the partners (ditto for Spartite if you have urethane in the partners). Moving the base of the mast forward will tilt the mast and increase rake, moving it aft will decrease rake. But the fore and aft position of the mast at deck level does not change.
When Imzadi was rerigged, we set the mast vertical in the middle of the partners and inserted the wedges. Then adjusted shrouds to hold the mast straight and vertical, took most of the slack out of the forestay and backstay, and then removed the sling used to stand the mast in position. Then the base of the mast was moved forward until the desired angle of rake was achieved (10" measured at the gooseneck, IRRC, but I could be wrong) and the stays were then tightened up. Finally the shrouds were adjusted to the desired base tension. Final adjustment of the shrouds was done with the boat beating to weather in about 10 knots of wind. I have about 2" of oak blocks in the mast step aft of the mast, and about 3" or 4" forward. With the base of the mast locked and the partners acting as a fulcrum, adding tension to the backstay bends the masthead back and adds tension to the forestay. The middle of the mast is held in place by the baby stay, so added tension to the backstay causes the bend in the mast to be nearer the top of the mast which tends to flatten the mainsail. What you say would be true, Josh: moving the mast forward would move the luff of the main forward (and BTW reduce J), but only if the mast remained straight and the movement would be limited by the partners to only an inch or two. Once the mast is wedged in the partners, moving the base forward increases rake and moves the luff aft. Rick Brass Imzadi C&C 38 mk 2 la Belle Aurore C&C 25 mk1 Washington, NC From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Knowles Rich via CnC-List Sent: Sunday, May 03, 2015 1:36 PM To: Josh Muckley; cnc-list Cnc-List Subject: Re: Stus-List LF38 Mast Placement in the Step Hi All. I've been having an offline conversation with Josh, see below. Perhaps someone else might like to answer Josh's questions as I can't. Rich Knowles Nanaimo, BC INDIGO LF38 Almost sold in Halifax, NS. On May 2, 2015, at 17:41, Josh Muckley <muckl...@gmail.com <mailto:muckl...@gmail.com> > wrote: Doesn't the luff moves forward when you move the foot forward? The original poster was asking about placement of wood blocks. He had all 4 blocks forward of the mast and the mask back all the way aft. I assumed that in moving the blocks to move the mast forward that this would move the foot forward as well. No mention of changing headstay length so I assumed it to be the fixed point in all of this. Based on these assumptions the trailing edge of the mast and the luff edge of the sail would also move forward but the mast as a whole would have more rake. Right? Josh On May 2, 2015 6:53 PM, "Rich Knowles" <r...@sailpower.ca <mailto:r...@sailpower.ca> > wrote: I'm confused. Since the luff is attached to the trailing edge of the mast, if the mast rake increases the luff must move along with it. Perhaps someone else can make more sense if this than I can for you. I'm at work but will post our conversation to the masses when I get home. RK On May 2, 2015, at 15:16, Josh Muckley <muckl...@gmail.com <mailto:muckl...@gmail.com> > wrote: What you said was that moving the mast aft moves the center of effort aft. Since the original question was about placement of the mast foot being all the way aft and the consequences of moving it forward I assumed you were referring to the foot. I had originally stated that moving the foot forward would increase rake and then mis-stated that increased rake would reduce weather helm. I was quickly corrected and I conceeded that more rake equals more weather helm. So what is the combined effect of moving the luff edge forward but increasing rake? The two actions have opposite effects correct? Josh On May 2, 2015 2:28 AM, "Rich Knowles" <r...@sailpower.ca <mailto:r...@sailpower.ca> > wrote: Moving the mast aft moves the centre of sail effort aft and increases weather helm. Simple geometry. Rich Knowles Nanaimo, BC INDIGO LF38 Almost sold in Halifax, NS. On Apr 30, 2015, at 11:15, Josh Muckley via CnC-List <cnc-list@cnc-list.com <mailto:cnc-list@cnc-list.com> > wrote: Moving the base forward should give more aft rake and reduce weather-helm. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Apr 30, 2015 2:13 PM, "N7FN--- via CnC-List" <cnc-list@cnc-list.com <mailto:cnc-list@cnc-list.com> > wrote: Hi, I need to know, from you 38LF owners, where in the mast step your mast is positioned. Right now my mast is all the way aft in the step but I can see that the mast was positioned in the step farther forward at one time. The only reason that it is all the way aft is because that is where the workers in the yard put it. Any ideas about how the boat would sail if the mast was positioned all the way forward as opposed to all the way aft? I have seen adjustments for moving the mast in it's step on some sports boats. Frank Noragon C&C 38LF, s/n 001 Rose City Yacht Club Portland, Oregon _______________________________________________ Email address: CnC-List@cnc-list.com <mailto:CnC-List@cnc-list.com> To change your list preferences, including unsubscribing -- go to the bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com _______________________________________________ Email address: CnC-List@cnc-list.com <mailto:CnC-List@cnc-list.com> To change your list preferences, including unsubscribing -- go to the bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
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