Author: Yrvind

I am grateful to Sharpii 2 for commenting on my “Next Boat”. On my web site I will start a blog for her titeld ”Boat-Ideal”. It will replace the blog “Lecture”. When building and sailing I always have the next boat in mind. When doing a mistake on the present one I say to myself “that I will correct on the next one”. And it helps; my boats have over time become better and better , very much better. I am very grateful for comments and for persons helping me pointing out my errors as it is difficult to objectivly observe oneself. However that is not always easy becouse often I do not express myself clear and English is only my second language and I am dyslectic, all which add to the confusion. There is also an other aspect and that is values. Most often my values differ as to comfort, speed, use of engine and more. Here engineering principles do not apply.
I will here try to do a bit of clarifying concerning sail area and speed. 1974 I sailed 20 feet 1.3 ton displacement Bris from Jamestown St Helena in the South Atlantic Ocean to Fort de France Martinique in the North Atlantic Ocean, necessarily crossing the Doldrums. Bris had no engine; not even an outboard. I could have put up more sail but chose to use only 4 square meters. I enjoyed the passage. The 3800-mile passage took me 45 days from anchor up to anchor down. That is an average speed of 85 miles a day or 3.5 knots. I found the voyage pleasant. The sail area/displacement was 3.4 if I have done the numbers right.
2011 I sailed the 15 feet 0.9 ton Yrvind.com 2900 miles from Madeira to Martinique. It took 45 days 64 miles a day 2.7 knots. The wind was more variable often so light that a candle could stand on deck without flickering, still the boat made 0.5 knots and steered herself downwind. I used very little sail. Most persons would be unhappy to sail at 2.7 knots. Me I was happy to spend six weeks at sea instead of three weeks. Me, when eating, I do not try to get the food down as quickly as posseble, me when making love, I do not try to get an ejakulation as quick as posseble, then why should I try to cross an ocean as quickly as possible? I am not racing. I am cruising. I enjoy being out there on the big, blue, wet, deep, endless ocean.
Still “Next Boat” has two 4.6 s.m. sails. In light wind going to windward I intend to use them if desireable so Sharpii 2 can double the number he got for “Next Boats” S/A relation. Sharpii 2 prefers sails his in tandem. That’s the common way. I differ, I think its more advantages to have them side by side like, the early airplanes, instead of one sail in front of the other becouse then they interfere less with each other.

A lugsail is only attached to the mast at the top. As the mast are pivoting I can move the mast top back 1.5 meter and forth 1.5 meter and with it the sail moves. Then I move the downhaul back and fort along the deck to suit. That way I can give the boat weather or lee helm as desired.
As to preventing leeway, the hull is five beams long and has very flat sides. In a way it works as a battering ram. It has very little frontal area compared to driving force. Norman Skene in his original book on yacht design always calculated lateral area as a function of midsection. Now it is calculated as a function of sail area. I do not agree. When heeled 20 degrees the leeward side present a lot of area to the water. Some of it will flow under the hull. That takes much energy. That energy creates a vortex floating along the bottom up to windward. Healed the bottom presents a bigger curve to the flow than the side making the water flow faster there. Bernulli says, the energy in a streamline is constant. This is classical two dimensional wing theory. High aspect wing have a tip vortex that disappears behind the wing. Low aspect bodies edge vortex sweeps over the surfaces combines with the fore and aft flow increases the particles energy. As the energy is constant in the streamline that energy is creating lift. That’s why the concord airplane could fly with an angle of attack of 45 degrees. Ordinary foils stall at 15 degrees. Its not efficient on the other had here we are recycling energy so its ok. This is my thinking on the leeboard and of course I lift them up sailing down wind. The rudders have even higher aspect ratio.
And of course I do not sail flat downwind. I always have the wind 15 or 20 degrees on the quarter.
It getting late but more will come.
Regards Yrvind.

Michael has been busy working on the models. Here are some more screenshots.

The leeboards angle of attack has ben reduced to 3.5 degrees which is satisfactory. Hatches and ventilation system has been added. No water will now enter even if the boat is capsized. Of course she is self righting to 180 degrees heel.

Keels, centerboards, daggerboards, chinerunners, and leeboards prevent leeway. Only leeboards makes no resistance downwind. A cruising boat spends a lot of time running downwind at anchor and in port.

The use of the two aft masts are: holding an awning/water collector, stanchions for lifelines, holders for GPS and AIS antennas (important these days)

Click on the pictures if you like to enlarge them.

Regards Yrvind.

After Pierre the illustrator Michael Tatschl is here helping to put my thoughts into rhino 3d models. He can be reached at:

m_tatschl@hotmail.com

I have changed the mast arrangement on Yrvind Ten. The two side by side masts is not longer connected by spreaders. A darling has been killed; there has been some give and some take. I deeply regret that I no longer so easily can climb the masts and that I lost strength. What I have gained is: the whole system is now much lover down and the hinge pin secured in a simpler way and as can be seen on the picture above one mast can be lowered if desired in strong winds. I have decided its an over all gain. Also I can give the two mast individual rake in light wind so that with the two sails up the do not interfere.

We have also been working on Pierre’s and mine next boats. They are small cruisers; here small refers to displacement not length. My next boat has half Yrvind Ten’s displacement and nearly twice its length. Pierre’s boat is a bit different mine is shown below going to windward in a breeze one mast up.

Abouve going downwind in light air. Thanks; yes we forgot to raise the leeboard. Things like that happens when you are excited and in a hurry.

Regards Yrvind

What you desire is a question of taste. Production boats are not to our taste. We like a boat that is small cheap and functional, have shallow draft, can be propelled by wind, wave and muscle power, a boat that can ride out any storm at sea and at the same time protect you from the weather, a boat that is directional stable upwind and downwind so that it do not need your attention.

This long and narrow boat meets these demands. Pierre’s boat is 5,6 meter long with a displacement of 778 kilos, my is stretched to 5,8 meter and have a displacement of 806 kilos. They have the same square midsection and a prismatic of 0,723. The draft is tolerable 19 cm or 7,5 inches.

The boats have balancing lugsails. There are two pivoting side-by-side mast and leeboards. The mast and leeboards pivot on the same axis. Because the section is square the leeboards will lay flat against the hull. Because the boats are small, they will attract small forces. The same mast and leeboard arrangement will not work on a bigger boat ( Galileo’s square-cube-law ).
This is the beginning of a project and as yacht design is an iterating process many changes will be made. Only the imbecilely never changes their mind.

One reason I like you to know this is that so that you will not think that my Yrvind Ten is a good cruising boat. She is twice as heavy has twice the draft and half the speed. Yrvind Ten is made to set a world record. She will be good at that and give me a unforgettable time at sea far from land.

Below are some pictures.

Pierre and me putting the modell together.

Abouve: Viuw  from below.

Above: Pierre inside the boat. The inside measurment is 1 meter. All that space comes from the square section.

Regards Yrvind.

After we had found a good way to do the book, Pierre, Maelle his girlfriend and me drove back to Sweden. Here I gave Pierre more material for the book. Pierre liked my boating concept so we decided to do a design that he could build; a design that also would suit my future needs.

Restricting a boat to ten feet is only good for records. I believe a boat should be long narrow and have shallow draft so my next one will be 7.2 meter long 1.1 meter beam with a draft less than 0.2 meter, displacement one ton, displacement lenght ratio 80 compared to yrvind tens 2500 . Pierre’s will have the same midsection but will be 5.6 meter long and have proportionally smaller displacement .

More about this is to follow – of course I will continue to work on Yrvind ten – just made some important improvement on the rigging.

More will follow.

Above me and Pierre at the mock-up of the midsection.

Above: Me and Pierre looking at the coordinates from a rhinofile of the hull a friend has done.

Above: Me and Pierre busy plotting out the coordinates for hulls; scale one to ten of the new boats.

Regards Yrvind.

I am now in Landevennec, Finistere, Bretagne, France. The reason; I have found an illustrator for my new book which I try to get published in english and french. His name is Pierre Hervé, a well known nautical illustrator.

For those interested in his work, please visit his website: pierreherve.blogspot.fr

Now we just have to keep working and find translators.

Regards Yrvind.

Welcome. Adress: Södra infartens företagscenter. Baumansgatan 4 Västervik Sweden Regards Yrvind.

Below some pictures First yrvinds safety spork

Below How to make a conventional spork. Start with a fork and a spoon.

Tejp them together and you get the product.

Picture below show how dangerously close to the eye the pointed ends of the spork can come when in use!

Regards Yrvind

First something about that inadequate planning leads to add on’s that becomes abortions. This statement comes from Manie B. I fully agree. It is much better to figure out everything in advance and not do changes. If your plan is not complete the project will get a life on its own and you are not the master anymore but just someone trying to put it back on track.
My problem is that I am not smart enough to foresee all the implications of my complex project. My brain is to small to in advance figure out how all the details interfere with each other. Therefore I end up with add on’s. However I do not consider all of them bad. Some will even be of great value for my next project.
Every time there is a restricting rule someone will find a loophole. It is ridicules to measure the size of a boat by length. It leads to absurdities like my swim platform. But the fact is that the European Recreational Directive’s harmonized rules, the International Towing Tank Conference, the US Coast Guard, the Nordic Boat Standard and other recognized bodies ,according to common practice, exclude spars, bowsprits, and rudders, bolted on swim platforms, pulpits, and other fittings from the measured length. Ange’lique and MoeJoe argue that my swim platform has buoyancy therefore it should be included in the measured length. I do not agree. Rudders are not included in the measured length and they certainly do have buoyancy, especially big ones with a fat profiles, like for example, NACA 63-021.
If my planned voyage can help to stop the stupid habit of measuring boats by length it would be a good thing.
Once again, every time a simple rule is in use people find loopholes. A complication that plugs the loophole mends the rule for a time and so it goes until we finally end up with one designs and the yacht designer is out of business.
I have never before built a boat to a rule if you do not consider the hole in my mother’s basement that I had to get Bris I through to get her out.
Adding on buoyancy parts is ridicules. Bolgers Folding Schooner is a good example of what it can lead to.
As for the seas smashing the swim platform. They build 60 feet long ocean racing multihulls that keep together. My engineering problems are order of magnitudes smaller. Do not worry.

About the video of Manie Bs margarine box. It looks like it has a ballast ratio of close to 100% and a very low center of gravity and an extremely low rotational mass moment of inertia. I do not think Manie B will have problems with stability at large angels of heel. But still to my mind his experiment is misleading.

Above the rule of the door. Difficult to find loopholes in. The best I could do was to remove the frame.

Below the boat Bris I comes out spring 1972.

Regards Yrvind

Here is a 3D model of Yrvind Ten 1500 kg . You can play with it, just twist and turn it with your mouse.  A tip: toggle full screen mode and the experience will be even better. If you are using a Mac-computer, use Firefox web browser. Michael Tatschl made this 3D model. You can contact him at m_tatschl@hotmail.com if you are interested in his work.