All posts by Vangelis Simonidis

“Tethys” hull #2

   Nowdays I am working on the construction of one more Tethys hull.  Actually I am building my personal Tethys boat because I have sold my old Marblehead some months ago.

This hull is no.2 came out of the mould and is made from a mixed Carbon Kevlar cloth. I wanted to use this kind of cloth because I had some spare in stock and I wanted to test it for the advantages some people describe.

I wanted to keep the total cost of the project in low profile and I decided to make my own fins. I used balsa wood for the core of the fins and 4 layers of carbon cloth on each side pressed into a mould I have made with the appropriate NACA profile shape.

I have even made a new ballast/bulb, shorter and lighter than the one I have made for the first hull.

The next thing I decided to do with this boat was to use a slightly shorter fin than the one in the #1 hull, and so this fin was cut 10cm shorter turned to be 60cm from water-line.

The bulb was fit to the fin and aligned perfectly with the hull.

The fins were also aligned with the vertical axis of the boat, and with the help of the building bench that turned to be very easy and smooth.

And as you can notice from the clocks in the background of the picture above I work late at night 23:25 … 🙂


The main deck got placed to the hull and I used a mix of epoxy resin and micro balloons as an ultra light filler to fill all the gaps and small surface defects. That material worked perfectly as it is very hard once fully cured and you can wet sand it very easily.

The hull treated with several grades of wet sanding finishing with 800.

After that, it was sprayed with an automotive grey primer and received it’s final wet sanding before colour painting.

The same primer was also applied to the fins and bulb…

(My excessive beard can’t fit inside any mask size…)

Got up early one morning and sprayed all parts with my cheap Asian but trusty small spray gun…

The chosen colour was a kind offer by a friend of mine who bought a bigger amount than he really needed for his full-size yacht.

Thanks Nikos…!!!

And voila…!!!

Bulb was also painted with the same colour…

While the fins decided to be white…

Here comes the first picture with keel fin and rudder fitted to the hull to see the colour scheme and how the whole boat looks.

Blocks, sheets post and mainsheet attached.

The name of the boat is “The Big Greek Machine” borrowed from a famous full-size Greek sailing yacht of the 80s owned by  P.Goulandris. I made a vinyl cut sticker and put it on the bow of the hull.

Below is a photo of the original yacht racing in the Aegean Rally on late 80s.


Stay tuned for rigging and sailing updates soon…!!!

“Tethys” Marblehead project


In November 2013 during the RG65 European Masters in Lavrion,  I met a skipper from the United Kingdom later turned to be a very good friend of mine, Mr.  Alex Cory.

Alex is an enthusiastic r/c sailor but much more than this, he is a great boat manufacturer.

After a lot of discussion and sharing of techniques and methods about boat building, I mentioned him my idea about the design of a new Marblehead hull.  Alex suggested me to get in touch with Mr.  Mark Dicks , who is a good friend of Alex and tell him my idea.

Everyone into the r/c sailing community knows  Mark Dicks who is a great designer carrying a great history on his back. He is the designer of the very successful  IOM “Triple Crown” as well as the famous  “Dragon Force 65”

Mark and myself exchanged tons of ideas on the design of a Marblehead project and eventually ended up in the design of a modern and narrow hull.  The hard chines in the bottom of the hull was a personal demand as most of the latest designs follow. After we gathered all the ideas and elements, Mark fine tuned the plans according to my taste and sent them to me to begin the construction.

The chosen name for the boat is “Tethys“.  In Greek mythology, Tethys (/ˈtθs, ˈtɛθs/; Greek: Τηθύς), was a Titan daughter of Uranus and Gaia, and the wife of her brother the Titan-god Oceanus, and the mother by him of the river gods and the Oceanids. Tethys had no active role in Greek mythology, and no established cults.[1]

I will not describe in detail how I constructed the prototype hull, as most already know the planking constructions technique,  but nevertheless I’ll let the photos to describe the whole construction …

When the planking works finished,  putty was applied on the whole hull and endless sanding initiated.

The project included making a polyester mould in order to take some hulls for me and some friends…

The mould was polished thoroughly and the first polyester test hull came out really nice.

After the first polyester test hull a carbon fiber followed with great success and look…

The construction of the first carbon hull started in the custom bench I have built for the proper alignment of the boat.  The boat is sitting on waterline and the keel depth is the maximum of the class (70cm).

The fins I decided to use are made by Dave Creed and their quality and stiffness are beyond my expectations. I decide to use the maximum draft limit of the class rules.

Mast tube for the swing rig is made from pvc plastic electrical tube. Struts made of carbon fiber plates placed to support side forces from the rig in heavy weather.

Brass tubes were used for inlet and outlet of the winch sheet lines.

The deck layout for the electronics pot recess and just before paint shop…

The completed hull just before painting…

After a week in the paint shop I received a shiny beautifully painted hull …!!!

This hull was build for a new friend of mine as he wanted to participate in the local Marblehead championship with it.  I installed all the electronics and built a swing rig for him. The sails came from Mr. Martin Roberts and they were excellent…!!!

The delivery and the launch day with the new boat owner was scheduled on April 2016…

A nice B Conventional Rig was build also and was fitted to the hull for stronger weather conditions…

The finishing positions after three regattas are very promising for the future. Below is the first race of the season into the Hellenic Cultural Centre water canal.

The boat needs further rig and sail tuning and a lot of practice from its owner. I am waiting for the final championship results to see the total development of Tethys.

To be continued…