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This project is born from our passion for classic boats (and a lot of naive ambition and dreaming). The boat is inspired by Brittany's traditional sailing work boats, more precisely the tuna fishing dundees. It is to be built of steel but have the charm and details of a traditionally built wood boat. 

The boat had to be as big as a crew of two could handle (The Cat and Dog don't take watches), that limited to a sail area of about 1700 sq ft, so a displacemnet  between 50 000 and 60 000 lbs was the target. The size would be just a touch smaller than average the 1850/90's size tuna fishing boat.

Here are a scanned images of the type of boat the Pepe Berrou will be.

Le projet est ne de notre passion des voiliers traditionnels (et aussi de beaucoup de reveries et ambitions naives).  Notre bateau s'inspirent des voiliers de travail breton, plus precisemment les dundees thoniers. Il sera construit en acier mais avec le but de lui donner le charme des details d'une vielle coque en bois. 

Le bateau ne peut etre plus  gros que ce  qu'un equipage de deux personnes pourra  manoeuvrer, cela nous limite a un plan de voilure d'environ 1700 pied carre, donc a une coque de moins de 30 tonnes. Le voiliers sera donc un petit peu plus petit que le tonnier moyen des annees 1850/1890.

Voici une images du type de bateau que sera le Pepe Berrou.

Design

(text en francais suit au bas de la page) 

Art or science? Boat design is both. A mix of intuitive and calculated choices always within standards (ABYC, Loyds). We started from our common knowledge, desires and mostly our aptitude to learn. We researched everything from industry standards to skills. Books, web, regulations, pictures, museums, trips, people....we don't discriminate any source of information. 

The objective has the looks of  the past but we would be fools  not to use the tools and technology today has to offer.

The lines were drawn with the marine design software package PROSURF using NURB surfaces. The hull modeling software is used to generate a hull surface of the desired shape, to fair it, provide lines, hydrostatics, curvature information and 2d expansion of the 3d surface. It is then possible to export all the geometric information as text files, so xyz coordinates, offset tables; or as different cad files like Dxf or Iges. PROSURF allows us to analyse the hulls curvature and provides tools to fair the shape in nice curves. We aimed for a shape that would compromise between roundness and relative ease to build of steel plate. Before obtaining the wanted hull shape, a few scaled models were quickly built to be stared at and discussed in the evening for hours on end.......Every proposed hull also came with its stability data (compiled with Prosurf and spreadsheets). The boat has to look good but it would be a bonus if it was safe and  sailable (ok, it's not a bonus but an important prerequisite).  

Once we agreed on a hull, drawings were exported to a generic CAD package for detailing and solid modeling. Drawing it once is like building it once. The construction grunt work is not all fun, having detailed plans drawn in the comfort of the office minimises the time spent sweating and swearing. 

The ribs and some other parts were numerically controlled cut (NC cut) from the drawings on a large plasma cutting table at Brannon Steel in Brampton. The ribs were fully detailed, I had the notches for the longitudinal and the limber holes cut in the shape. This was a huge labour savings as all the parts are perfectly cut and the ribs went together within 1/32 of an inch. The files I sent to get parts CNC cut were 2d dxf files, projections of the parts profile. I use Dxf as most cad software can import and read those files. I divided my ribs in pieces that would be easiest nested, there would have been way to much waste if I kept each rib ring intact. That meant  welding later the parts together to reform the rings but was the best way to make it economical. The NC cutting shops should have a nesting software to organize all the parts as efficiently as possible on the plate so the positioning of the parts on the file sent to them doesn't matter. I only had to make sure that all the parts were small enough for the max size plate the shop could cut.

I didn't get the plating of the boat NC cut. I didn't think the gain was worth the risk of a plate not quite fitting the frame. A very slight misalignment of a frame, which otherwise would not be a problem , could cause the plate to be that 1/8 of an inch off. We templated all our plates and cut them out of regular plating and it worked great with very reasonable waste. I used the plate expansion from probasic to plan the plate size I would need and how much material to buy but didn't use it for cutting. 

Murielle did all the design and CAD work for this project. 

Art ou science? Le design d'un voilier est un peu des deux. Un melange de choix intuitifs et calculs, toujours dans les limites des normes (ABYC, Loyds). On est partit de nos connaissances respectives, nos desires et surtout notre aptitude a apprendre. Il nous a fallu apprendre de tout, des connaissances aux techniques. Livre, web, reglementations, photos, musees, voyages, rencontres...nos source d'information sont sans bornes. 

Le produit final a les aspect du passe, mais nous serions idiots de ne pas profiter de la technologie actuelle pour arriver a nos fins. 

Les plans de lignes ont ete dessines avec le logiciel  PROSURF. Prosurf permet d'analyser les courbes de la coque et fourni les outils necessaire pour les lisser en une belle forme reguliere. Notre but etait d'obtenir un juste compromis entre une coque tout en rondeurs et pas trop difficile a construire avec de la plaque d'acier. Avant d'arreter notre choix sur une coque nous avons construit plusieurs models reduits que nous avons regardes et discutes sous tout les angles des jours et des nuits..... Chaque coque consideree venait avec des donnes sur sa stabilite (compilees avec Prosurf et dans des tableaux de calculs). Nous voulons un bateau esthetique mais ce serait aussi bien qu'il soit securitaire et un tant soit peu marin (d'accord....plus que bien, essentiel). 

Une fois la decision prise quand a la forme de la coque, les dessins ont ete exportes vers un logitiel CAD plus general pour y construire un model solide et elaborer les details. Dessiner un model c'est comme le construire une premiere fois. Le gros du travail de construction est physiquement demandant, travailler a partir de plans detailles dans le confort du bureau minimise le temps passe a suer et jurer au chantier.

Les couples et plusieurs autres composantes ont ete decoupes sur une table a decouper au plasma a controlle numerique chez Brannon steel a Brampton. Les fichiers de decoupe ont ete produits a partir des fichier CAD. Cette route a ete une economie incroyable en temps de travail, d'autant plus que les morceaux etaient parfaitement coupes et que la charpente a pu etre facilement assemblee dans des tolerances de 1/32 de pouce. 

Murielle s'est occupees de toute la conception et des dessins pour ce projet.