Welcome to Yrvind´s website: small boat designer, builder, sailor & writer
Below are some pictures confirming correct displacement.
The planned weight of Exlex Minor is ready for 5-6000 nautical miles is 800 kilos. The 1/10 modell weighs 0.8 kilo. Dipping her in the workshop baisen conforms that the draft 20 mm corresponding to 20 cm on the full scale boat is correct, correct .
To make it easier to see the waterline I have added some sawdust to the water. Click once or twice to enlarge.
Sawdust is a good thing for many uses.
To be continued…
Regards Yrvind
Thursday night late I was back home in Västervik determined to get sailing in a new boat, Exlex Minor, 5.8 X 1.12 meters as soon as possible. Hence after sorting out several bourgeoi duties like mail, bank, internet I was back in workshop designing.
During my 40 days at sea I had well prepared my mind.
Nowadays yacht designing is almost exclusively done by computer and that is an excellent way of doing it. In the 70- I designed by ducks and splines. Later I got help from clever people with computers ,like John Letcher, Rolf Eliasson, Matt Layden and Guy Liljegren. At sea I thought of an other way.
Given a boats lenght, beam and draft there is a very simple way of figure out displacement using the prismatic coefficient. Prismatic coefficient is the fullness of the hull. 0.54 is common for sailboats. Sailboats also usally are 3 beams long, Exlex Minor hovewer are more than 5 beams long. Boats with a good lenght ratio can have higher prismatics. A higher prismatics gives more stability and a higher top speed for a given waterline lenght. I chose 0,7.
By multiply the midsection area by the lenght of the waterline by the prismatic the displacement is fond. In the case of Exlex Minor it is very simple just multiply beam by draft as its an rectangle
Exlex will have a waterline of about 5.6 meters she will have a beam of 1.12 meters. At 18 cm draft she gets 790 kilos displacement. At 20 cm draft ( about 8 inches) she gets 878 kilos displacement.
I started with a block of wood 58 cm long 5.6 cm vide and 9 cm high the bottom part was of MDF board to indicate the underwater part. The tricky part was to get the prismatics right, but as I have been around boats for a long time I got a sense of their shape. As they are usually 3 beams long I imagined a boat 3.36 meter long cut it in middle and added enough midpart to make it 5.8 meter long. Cargo ships are designed along similar lines, a forword part, an aft part and a parrallel middle section.
After shaping a half modell I made offsets of the surfaces and made a model.
Below are some pictures.
The wooden block being glued.
Clamping 3.7 mm plywood to the half modell to take off the lines.
The modell
The modell on a chair. More work will be done to her like giving her a spoon bow and make her waterproof. That done I will load her to 0.8 kilos, she is an 1/10 scale modell and float her to find her waterline.
I thank everyone who has donated money to help me with my project and get me back from Madeira. My economy has now crashed and I need to get plywood and other items for an full scale sailing modell before starting on the sandwich composite boat. I hope you will continue to support me. Me I will let everyone for free use my ideas and drawings as published here to build small safe enviromentally friendly boats. I really think I am into something new a good, a mountain bike for the oceans.
To be continued…
Regards Yrvind.
I am back home. There is many things to sort out, for example to get a new internet connection.
As soon I am settled I will start working this site and build a new and better boat called Exlex Minor with a length of 5.8 meters, beam 1,12 meters, draft of hull 0,18 meters and displacements loaded for 60 days at sea, 800 kilos. That will give approximately 5000 nautical miles. The building of this boat will be presented on this blogg.
I take the opportunity to thank everyone who has contributed to my last project, because at sea I been unable to express my gratitude.
Regards Yrvind
Video made by Andreas Eidhagen
Yrvind is now on Porto Santo. He has decided to restart with a new boat. ExLex, which is basically an experiment, has some issues that must be solved. For example is the boat too heavy, which affects both speed and stability. There is a serious problem with the stering control that causes the rudder to lock. It is too cramped inside and it has not been possible to handle the sail from the front hatch as it was intended. All in all, this means that Yrvind decided to make an restart and design a new boat where these problems is corrected. Yrvind now needs to rest and comes when he feels ready with a status update here on the website.
Yesterday was a difficult day with grey skies and much wind from the side which is the worst. Many times I had to go on the wobbly foredeck to work the centerboard and sails. This is not how it should have been done. It should have been done from the safe position of the fore hatch. The road to hell is paved with good intentions. At first everything looked fine, then in the last days when the timetable was set, came a rush. The forepeak got filled up and its intended use as a safe place to handel the sails and centerboard was temporarily sacrificed. I eat myself to more space was the idea.
Surprisingly even after eating for now more than a month it seams as if I have as much provisions as when I left Ireland. I still have to work from the outside from the foredeck. Unfortunately because I do not feel completely safe there in the dark when the boat is healing rocking and yawing. Then the night was difficult to but in a different way. I am now in the really shipping lines for traffic to and from the Gibraltar straight. Some was coming very close. It is difficult to know if the crew is seeing me or not and I hate to bother them by calling them on the VHF. Everything went well and I awoke to a wonderful day. The wind had calmed down and the sun shone brightly from a clear blue sky. It was wonderful and very nice and warm. Then the horror of it, the port rudder did not work. It had jammed and was blocked in a position. I tried everything but to no avail. What to do? I did some thinking. I was sailing south. The hot morning sun did strike the port side. I have inside steering and no wind-vane or autopilot. The pipe steering lines goes to my bunk. I do not want any water there, specially not seawater. The trough hull connection consist of a piston mobbing in carbon fiber. To each end of the piston the steering rope is attached. Thus breaking the wicking effect and making it waterproof.
My boat is very narrow only 104 centimeter. She floats to deep and is very tender and rocky. I therefore use a lot of antislip tejp. They come in two varieties, black and white. To my yellow boat I thought black looked best. Black do get very hot in the sun, in fact it is uncomfortable to touch it. The heat produced by the black antislip tejp had so heated the piston that it had expanded and jammed in the pipe. I have now pealed it of. Now the piston is cooled and it seams as if the steering once again is a working construction. I have wanted to mention this as an example of how two things at first not connected to each other can interfere and cause big problems. One can not new things without testing them. Problem is here at the latitude of Gibraltar the sun is much stronger than in Sweden
I have a nice time out here. I spend my time working on Next Design which is coming out most satisfying.
Regards Yrvind
Update to sailing report 6
I still have a problem.To day again the sun is shining brightly. Again the port rudder is blocked. I was happy yesterday. I thought I Had solved the problem by removing the black anti slip tejp. I hope I can come upp with a solution.
Regards Yrvind
Update 2 to sailing report 6
The rudder problem gets worse and worse. Now in the afternoon when the sun comes in from the other side also the starbord rudder is blocked. I cannot steer my boat. Its a bad thing. If a ship is heading for me I cannot move out of their path. I try to find a solution.
Regards Yrvind