Capitol Yachts was in business from 1971 to 1996 located in Harbor City, CA.
Owners were Bill Smith and Jon Williams and boat designs included C & C yachts which was interesting.
Kenyon and Isomat at one point was Kenyon Isomat. Not sure about the relationship with Sparcraft of CA but Jim Kulibert, sales manager, with Kenyon ISomat and later with Sparcraft in Charlotte, might know but he is retired. I have a phone call into him to see if he can identify. If he responds I will let you know.
Scott T-Bird suggested Rig Rite.
I found a contact on the internet but not sure if it is a good one.
email is: Kenwallace+Capitalyachtsinfo@gmail.com
I will call you if I hear from Jim Kulibert if he knows who it is