38 tuning
Craig,
Wow, I had not seen that document (the tuning guide) in years-note the initials at the bottom (SM)
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The good news is I can explain the "mast at the fwd end of the partners" thing:
This is not something a cruiser or even most racers need to worry too much about. It has to do with the J measurement as measured for determining the rating-NOT proper tuning. The cutouts may be just slightly too far aft in the deck, and to make sure your actual J (16.25) is correct, that was where the front of mast needed to be. The J is measured from the front of the mast to the intersection of the hull and deck at the bow (the stem).
Remember that genoa LP (155%, 125%, etc) is a funciton of J, as are the spinnaker girths (assuming your pole is no longer than the J). So, if your J is 16.25 feet, you maximum genoa (if your local PHRF allows 155%'s) would be 25.18 feet (1.55 X 16.25). For the kite, the max girth is 1.8 X J. Or, if your local PHRF assumes 153% instaed of 155%, then the biggest genny would be 1.53 X 16.25, or 24.86 feet. Remember the ratings are in part derived from the I,J, P and E. The larger these are, the bigger your sails would be (e.g. if your mast was back in the cutout and your J measured in at 16.75 feet, a 155% could have an LP of 25.96)-bigger. But, bigger rig dimensions= bigger sails and a faster (lower) phrf number. It would no longer be a "standard 38".
Since the 38's PHRF ratings are based on a J of 16.25 you want to make sure your sails are maximum for that J. If they took an individual boat and rated it with a larger J, you COULD now have a bigger genoa, but you would rate faster.
Under PHRF, thankfully, as long as your sails do not exceed the maximum for the dimensions it was rated under (I of 50 and J of 16.25 in this case), they don't care if the mast were slightly farther aft.
Which is a long way of saying do not worry about getting the mast fwd in the deck cutout.
With respect to the fwd bend issue, it sounds like your problem MIGHT be too long of a backstay, but MOSTLY I think you can fix this by having your fwd and aft lowers set up correctly. Make sure the fwd lowers are noticeably tighter than the aft lowers, but get them both snug-with just slightly less tension that you have on the uppers. And for now, get the backstay as tight as you can.
This will induce some aft bend in lower half of the mast (the middle of the mast will poke forward). The main will set up a bit flatter, but it should prevent the mast from bending forward at the top.
So, I would put the base of the mast in the middle of the mast step, and locate it in the deck cutout so that it goes straight up, or has the slightest aft angle. If it is slightly forward (as seen in the cabin between the step and the cutout), the move the butt slightly forward until it looks straight up and down. Then set up the rig as we have described here or in the tuning guide from 81.
Sorry if this hazy-I was on doing Beer Cans last night on a J105!!
I have indicated you don't want forward BEND ever-and this is true. And for a cruiser, you should not have fwd RAKE generally. However, once you have the BS ADJUSTER rigged, you COULD in effect rake the mast forward when sailing downwind-this will reduce weather helm and make you a tad quicker downhill. All you need to do is ease the BS off completely when running (some folks take a genny halyard to the tack fitting and grind it snug to full te top slightly fwd.),. This lets the top of the rig fwd. HOWEVER cruisers should not worry about this-it is a racing technique used to maximize downwind speed, and may be more "intense" than your crew is up for..
BTW-I am now a "recovering " sailmaker, no longer in the business (although I still have contacts). I ran the Chicago Quantum Sails office from 2000-2002, and then co-ran the Chicago Doyle loft until late 04-then left sailmaking-but that is where I worked while saimaking in Chicago. My only ties to "the industry" now are that I do some on the water coaching and speaking engagements.
Cheers,
S
