Zipper is a 225 class hydroplane by john l hacker. this 18 footer was specifically design by hacker as a racing craft. it features all original sizes and dual cockpits.. Clark craft offers hundreds of boat plans, design patterns, and a full line of boat building supplies and accessories for the amateur boatbuilder.. About the plans: i am not a naval architect, or an engineer, or even a draftsman. i am a forester by education, a furniture-maker by profession, and a boat-builder, sailor and racer by inclination. i have built a number of boats over the last 35 years or so: from the 8-foot hydroplane i built when i was fourteen, to a 21-foot sailboat built in the 1990s, and a bunch of tunnel and v-bottom.