Randy;
I could have sworn that I have seen a table that lists the initial mast rake for various C&C models built in the 70’s, but I’m not able to find it. The rig tuning information on the Photo Album, and the information in the owner’s manuals that came with my 25 mk1 and my 38 mk2 all show the same information about setting up the mast rake: On a 24, the target for initial rake is 6” measured at the gooseneck. For the 38, the target is 10”. Looking up the I dimensions and doing a little math says the initial target for your 30-1 would be 8” of rake. But the instructions indicate (and this could have changed over time) that some sailmakers prefer no rake when they make the sails, and caution against having any forward rake in the mast. The process recommended in the manuals is to set the mast up (close to vertical is implied) and then adjust the forestay and backstay to achieve the target rake. Then put in the mast wedges, go sailing, and do any appropriate tweaking. Your post indicated weather helm in 30 knots (I’m presuming apparent) with full main and #2 genoa. I’m not surprised. With wind that strong and a full main I would expect the boat to be standing on its ear and rounding up unmercifully , or to see that the main was trimmed almost fully out and basically flogging. I find that both of my boats are fastest and most comfortable with a max of about 18-20 degrees of heel, YMMV, so I tend to reduce sail in the following pattern: About 15 apparent – reduce genoa (starts from 155 on the 25 and 135 on the 38) About 20 – 1st reef in main About 24 – reduce genoa again (which brings me to a 110 Lapper on the 25 and about 100% on the 38) Depending on conditions but around 26-27 – 2nd reef in main Remember that the force generated on the sails is proportional to the square of wind speed, so wind at 20 apparent generate 4 times the force of wind at 10, and wind at 30 generates 9 times the force at 10. So the boat will go just as fast with smaller sail up in higher winds. Anyway, in response to your initial question, my recommendation would be to set up the mast step so the mast was vertical – or nearly so -for an initial position and then adjust the rake with fore and aft stays per the C&C instructions. 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 RANDY via CnC-List Sent: Saturday, March 25, 2017 3:12 AM To: cnc-list <cnc-list@cnc-list.com> Cc: RANDY <randy.staff...@comcast.net> Subject: Stus-List Mast Step Pitch & Helm Balance Listers- Seeking your input here. I'm in the middle of the mast step rebuild project a la http://cncphotoalbum.com/doityourself/maststep/maststep.htm. Lots of pictures of the project at https://drive.google.com/open?id=0B-NqAxQ6JxFTSzRLbFo0NDl6U1E. I'll be cutting new supports from laminated GPO-3 slabs Saturday night or Sunday morning. Before installing the new supports, I have to decide on the elevation of the aft support. Of course I took careful elevation measurements from the cabin sole before removing the original supports. But the question is, what was the original shape of the top of the aft support? I believe the middle of Grenadine's aft support, under the mast step block, was compressed down from its original elevation due to a combination of weakness in the support and standing rigging tension (especially backstay). Have a look at the pictures and you can clearly see what I mean, e.g. https://drive.google.com/open?id=0B-NqAxQ6JxFTLXZuXzd1T1pkR28. This compression has the effect of pitching the mast step aft, thereby moving the masthead aft, thereby increasing weather helm (which I've definitely noticed under enough wind and sail - it was strong under full main and #2 genoa in 30 kts, not surprisingly). However I also believe that the original elevation of the aft support may have been carefully tuned for helm balance, prior to compression below the mast step block due to weak wood and standing rigging tension. The reason this elevation question matters so much is because, using trigonometry, I can calculate the distance by which different elevations of the aft support will move the masthead forward or aft, which in turn will affect helm balance. Each quarter inch of aft support elevation difference could move the masthead about three inches I believe. The last picture (https://drive.google.com/open?id=0B-NqAxQ6JxFTU3hRNmZoMUU1MFk) in the Google Drive folder linked above shows the templates from which I'll cut the new supports, traced from the original supports removed from Grenadine's bilge. I hypothesize that the dashed line I drew at the top of the aft support template may have been the aft support's original elevation. I'm halfways tempted to split the difference and cut the new aft support to have that elevation. Of course, I could be full of crap, because I tune the mast rake using the stays after all, which probably influences helm balance more than mast step pitch. And of course I can control the sail selection and sail trim, which probably influence helm balance more than mast step pitch. However, for a given sail selection close-hauled, with neither the backstay nor forestay over-tensioned, the mast step pitch would certainly influence the masthead position and therefore the combined center of effort of the sail plan. What say ye? Does anyone out there know if the top of the original aft mast step support on a 30-1 was flat all the way across, or did it come from the factory with a little elevation drop to tune helm balance? I'll be committing an assumption about that to a GPO-3 slab with my jigsaw in the next day or two. Thanks in advance, Randy Stafford S/V Grenadine C&C 30-1 #7 Ken Caryl, CO
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