1974 mac 21 boom height

[mark Milson]

I bought this boat in feb 09. I,m questioning wheather the main is for a 21 ft venture.I have two holes drilled in the mast for boom bolt. They are about six inches apart. Can someone tell me what is the exact measurment from the bottom of the mast to the center of the bolt hole in mast for boom gooseneck? When i use the lower hole ,the top of the sail hits the backstay. I,m thinking about maybe altering the sail to make it smaller. But i need to know what the true hole is for boom bolt before i can do that. Thanks

 

[Knuttle]

The mast on the original Venture/Mac 21 was 24'.

The dimensions of the main are:
Model Sail Type Luff Leech Foot
Venture
21
Pre '80 21'10" 23'4" 9'9"
Venture
21
Post '80 21'7" 23'1" 9'9"

That leaves about 30" above the deck. Stretching the sail with the downhaul will make that even less.