CB repairs
Use epoxy resin(West System or other) and woven glass cloth. Cutting on the bias achieves two benefits, Less prone to unravel as well as much easier to conform to compound shapes. I would recommend doing the entire perimeter and tapering back from the edge about 3". general rule is...
CB repairs
I would be surprised if most if not all of the boards didn't crack. After seeing that there is no glass cloth or matt joining the shell halves, only a mix of thickened resin, it seems very likely to split as mine and others have. If water has not rusted the steel core of yours and...
CB fit
The centerboard on ebay appears to be in nice shape. Extremely unlikely that there were any differences between years other than evolutionary changes in rigging. What happened to your CB?
Terry
I have an original main from my E25CB for sail. It is in good condition, no tears or serious stain spots. $200 firm
I'll gladly send pictures and answer specific questions. I had a new loose foot sail made and won't be needing this.
Terry Steller