Day Cruiser 9m08 BOOK

Amateur’s Notebook is part of a series of books oriented to “Art of making boat plans” using Rhino® software.

Boat and Yacht plans proposed in this series are built around Classic hulls which are represented from their basic curves up to detailed upper structures.  

By learning the design technics, the reader may modify, change and replace any shape or curve representing the form in order to obtain his (or her) own needs or requirements.

Each book is independent and will not refer to some portion of any other book. Each book mention one autonomous hull shape. A reader who purchases several copies may obviously encounter some similarities between texts. This is due to central path of design philosophy which is common to most hulls. However, each hull may be represented using very different “HULL curves”.


The hull represented in this article is a Day Cruiser 9m in length (LOA) by 3m width (beam). The design is made with simplicity in mind: easy to design, easy to build. One simple bottom slightly curved from bow to aft and two sides will form the essential shape of the hull. Front cabin and wheel house are protecting passengers from bad weather while travelling and fishing. There is enough space for 2 people for a week end to visit either lakes, estuaries or doing some coastal navigation. The internal layout is not fixed nor included in the design process.

The book starts with basic curves of the hull. Step after step, every detail is explained. This includes the design technique and also the elaboration of hull structure. Every design step is clearly explained from inside of Rhino.  

Hull curves are faired and explained same as hull surfaces which are wrapped around these basic curves. Virtual pictures provide a clear view of final result and also let the precise plans elaborated.


Important structure elements –such as motor, shaft and propeller- are shown to give an idea of how they may be implemented. Details for these elements are left to the Shipyard, Naval Architect or anyone who has some fundamental experience on boat building techniques.

The book is a valuable source in learning how to make the design of a hull. Every “frame” is drawn with millimetric precision. Thickness is fixed to 6mm (approximately) but the profile is not imposed to a “T” or “L” or any other known shape. Details in this area will depend on the experience of Builder or Shipyard.