Building S420

 

Most of my boat projects remain in my dreams, or in the computer's memory. However, if I preserve in obsessing about a design for a long time, if it makes me think about it during night, then I refine the drawings, and build a cardboard model of it. If I still find it interesting afterwards and if I find the space and make time to build it, I go for it.

This is what happened with my sailboat named S 420.

It all started on October 22^nd, 2019. On a sunny day I went to buy the plywood. I bought 5 sheets as per project and tied them on the roof of my car (after removing the bike racks). In the following few months I did the tracing. It consists in translating the dimensions from the drawing to the plywood with meter stick, tape and pencil. The curves are done by connecting some points with a fine flexible stick. Then I cut the pieces from the plywood with the jigsaw. I worked for few hours a week until the end of November, when it became too cold for starting epoxy jobs.

After few months, when temperatures raised, on March 15th, I came back to the garage. I had time, since the Covid19 lockdown was in full swing. I glued together the bottom and side parts of the planking. I prepared the stands to put the future boat on.

The bottom panels are stitched together, and the ribs are prepared.

The ribs are put in place for testing. The bottom planks are laminated together with a glass tape satured with epoxy.

The ribs are epoxied to the bottom. Creativity and force is required to make the bottom planks follow the ribs shape on some locations.

All the ribs are glued to the bottom. The top side of the bottom stripes is covered with epoxy. Ribs are connected with battens that will support the deck.

After the bottom and the edge surfaces, the side surfaces are put in place. All the interior surfaces are coated with epoxy resin.

The deck is test placed, and the bow is glued to the stem.

The inspection holes are opened and the daggerboard slot is cut out. The bow deck support structure is being built.

Then the time to work on the external surfaces arrived, on the bottom and on the sides. I turned the boat up-side down on 4th July. I faired the edges, made them soft. Then I laminated the glass tape strips on the edges. However, my phone fell in the sea so I lost some pictures that show these parts of the process. The following pictures show the lamination of the whole bottom. This was followed by some sanding in order to obtain a fine surface and application of some putty in the critical spots. Then two layers of primer and two layers of two component final paint are applied, with the inevitable sanding between each of these layers. 

Then the hull is again turned back, and the front deck and side bench elements are trimmed to the correct dimension following the sheer line of the hull. The parts are gradually glued to the hull and covered with a layer of epoxy resin and paint.

Then I worked on some of the details: oarlocks, the mast slot, the rudder and the (synthetic) teak deck.
 

This was a true building adventure. It came to the end in October. It became too cold for working with epoxy. But it was almost completed. It took me about 160 hours, spread through 8 mounts. After this I had to varnish the an old Europe class mast I got from a friend (it was also extended on the bottom), build a canvas cover and a small trailer. 

 

S 420 sailboat cardboard model

 

When I dream of building a boat, I think about it a lot. First I draw it with pencil on paper. Then, I do the model in 3D with the FreeShip software. I often develop many versions of the design. For instance, when I was evaluating this project, I was considering designs from 380 cm to 450 cm in length, with or without the double floor (self bailing), for instance https://seawoodcraft.blogspot.com/2018/10/s-400.html

After the virtual models, when I decide for a "final" version, I build a scale, cardboard model.

 

 

S 420 - Sailboat

 

Idea

I would like a small enough sailboat to tow it on a trailer to a slipway or a beach behind a small car on my own, to launch it and retrieve without problems. I remember some off-season sailing sessions, when the bay was empty and quiet, unlike on summertime.. I do not easily find the time to organize a crew. Further, some people think that you can not sail and enjoy the sea in autumn, spring or even winter. They do think it is too cold, but there are beautiful days. These beautiful memories make easier to wait until next summer. There are many dingies that offer this. But I would also like it to have a big cockpit that allows a friend or some children as crew. I would like that, when there is no wind, I can return ashore by oars. I would like to have enough stability to fish from it, to sunbath and go swimming. 

Description

The sailboat is 4.15 m long and 1.64 m wide. It has a 2.5 meters long, flat, self-bailing cockpit. In front, there is a deck that covers a decent dry storage compartment where all the gear can find place. On the deck, a 5.5 meters aluminium mast is inserted. The sail is similar to the Europe dinghy sail, but different variations can be made. Oars can be stored under the side decks. A removable bench can be mounted in the central position and removable oarlocks can be inserted in the side benches. This allows two oar rowing, even if it is not the main purpose of the boat. The boat is made of 5 2.5 x 1.7 m, 6 mm thick marine grade plywood sheets, laminated with epoxy resin. The size of the boat is similar to a great number of other dinghies, but the cockpit is bigger, which make it more suitable for recreational use. As far as size, it can be compared to a Laser, but the capacity is more similar to a Megabyte. The style is inspired by the Truk 12 dinghy. The construction method is similar to the Farr 3.7, but much simpler. A pair of wheels on a specifically made support allows to move it ashore, on the parking, or beach, from the trailer to the beach. The cockpit can be refined with artificial or natural teak.