Most Odays of that era used a sliding gooseneck.
Unless the mast head sheaves are 'frozen' and unable to turn freely, your problem 'may' be how you set the sliding gooseneck
before you raise the sail.
Here's how to raise the main with a sliding gooseneck to achieve maximum hoist of the mainsail.
1.
unlock the gooseneck and slide it as far 'up' as you can
before raising the mainsail.
2. Raise the main 'as far as it can go'.
3. Most of these boats had wire-to-rope halyards ... so there will be a several small 'balls' swaged onto the wire portion of the halyard .... the ball goes into its 'ball-cleat' --- you dont attach the 'rope portion' of the halyard to a horned cleat, etc. Two types of ball cleats --- one version requires that you simply slip the halyard ball into the 'ramp' of the ball cleat; the other version has 'sharks teeth' onto which you slip the loop of the swaged wire over one of the 'teeth'
Note - sometimes the ball cleat will be near the gooseneck on the mast, sometimes the ball cleat will be near 'the top' of the mast or 'well up' the mast .... all depends on who originally set up the boat when it was 'new' !!!!!!!!!
4. Once the mainsail is
fully raised as far as it will go, loosen the 'pin' on the gooseneck fitting and (pull) slide down the gooseneck to the 'top of the black band on the mast' OR pull down on the sail/boom (stretching out the boltrope) by approximately 1-3/4" to 2" and lock the gooseneck. Some sliding gooseneck arrangements will have a 'downhaul' rope which attaches and is held fast to the mast via a horn cleat ... usually near the 'deck' to 'lock' the gooseneck.
In any set-up with a sliding gooseneck, the 'final' adjustment is always pulling
down on the gooseneck to TENSION the boltrope on the mainsail. (That final tension is what holds the halyard in its ball cleat or sharks toothed cleat, etc.
Note - if the wire-to-rope halyard has been replace with 'all rope' .... consider to replace the 'rope' with high-tech
LOW STRETCH rope such as "dyneema", etc. If the boat's mainsail halyard is set up with 'ball cleats' or 'sharks teeth' cleats on the mast ... best is to get a rigger to replace with a new wire-to-rope halyard with swaged-on balls on the WIRE - such old style wire-to-rope halyards dont last very long, but are
unsurpassed in properly 'setting up' a boat's dacron mainsail luff tension with a sliding gooseneck.
Once the mainsail is in proper position (fully raised into its 'up' position), go to:
http://forums.sbo.sailboatowners.com/showthread.php?t=120970 see post#1 and read the directions on how to properly set the tension in the boltrope and to check its 'condition' - if it has become shrunken in its length dimension and needs to be corrected by a sailmaker. You can also DIY do minor correction to a boltrope to restore its proper length if you have a sailmakers 'palm', a stout sail needle, and waxed sailmakers twine, etc.
