Original 1st printing 21 x 21" benefit* concert poster for the second "Pirate's Ball", a Hells Angels-sponsored boat cruise (aboard the "S.S. Duchess") around New York City. The event featured the Jerry Garcia Band (with Keith & Donna Godchaux) appearing with Elephant's Memory and Bo Diddley and was held on 9/15/1976. *for Sandy Alexander (Hells Angels NYC) Legal Fund 

Designer unknown ("C.A."), the handbill/flyer image is featured in the Art of Rock on page 403 (plate 4.218), this is the LARGE poster with a completely different design. 

Medium flat index stock poster is in good (B) condition; there is about a 3/4" diagonal chunk out of the lower right corner tip, along with tack/staple holes in the other three corners, a 1" tear in the bottom center margin (sealed on the reverse with clear tape), a 3/4" tear in the lower right margin, light handling wear, a touch of toning, a few stray thin stress bends and a pin-prick surface spot or two hiding within the image area, a series of nearly-invisible horizontal roll bends and a bit of light staining on the reverse, otherwise fine.... not perfect, but not totally hammered, either. 

 An overall decent example of this semi-hard-to-find Garcia/HAMC item from a WILD party/event (which included N2o tanks on all decks provided by none other than "HIGH TIMES" Magazine), check out footage of the event HERE:

https://www.youtube.com/watch?v=jYZ2hOWWyv8

photo: c. Arthur Field/Relix