Step 4:

Center the bottom in the jig, stand on it to bow it and hold it down, and temporarily screw it to the 2" x 4" 's 130mm each side of center line to allow for gluing of the doublers without covering the screws, so they can be removed later.  The holes will be filled in when the boat is removed from the jig with epoxy.  Rip a 4' x 8' sheet of 4mm plywood into 1- 240mm strip and 2-80mm strips with a 45 degree beveled edge.  This can be done on the ShopBot or a table saw.  These are the doublers for the bottom to meet design minimum thickness while saving weight.  Once these are epoxied into place and trimmed you are ready to install the sides, mid ship frame, bow and transom.  The mid ship bulkhead can be used to position the strips in the correct place on the bottom of the hull.  Once these are epoxied in position, placing some weights on top, until cured, works well.  You will be covering the dagger board slot, but that can be easily cut out once the hull is removed from the jig and turned upside down for fitting the dagger board trunk and filling of screw holes.
<p>Thanks for your inspiring post ...</p><p>started on 29-Oct-2015 by cutting my CAD plans into plywood (hull) and chip boards (temp frame)</p><p>crossed the finishing line on 14-Aug-2016 with a successfull Maiden Voyage after ca. 200 hours of building</p>
<p>Hello, Mike</p><p>Would you mind to share your CAD drawings ? We are going to build several boats for our school, so, your CAD would be helpful</p><p>Thanks a lot in advance</p><p>Andi<br></p>
<p>Here you are ...</p><p>all dwg are AutoCAD 2014 format</p><p>rumpf.dwg ... complete cad with all 2D and 3D elements on various layers (rumpf = hull)</p><p>all CAM files (Schnitt = cut) are 3D Polylines with some short parts of the lines elevated by half of sheet thickness so that all parts remain in their sheets. You need to see if your CAM device (router) can handle these lines where at some points there is only Z movement, without any XY movement ... our router had some problems with that</p><p>3D Schnitt 06mm Okume 1.dwg ... 1st sheet plywood 6mm</p><p>3D Schnitt 06mm Okume 2.dwg ... 2nd sheet plywood 6mm</p><p>3D Schnitt 12mm Okume 1.dwg ... sheet plywood 12mm</p><p>3D Schnitt 19mm PSpan 1.dwg ... 1st sheet 19mm particle board - produce 2 times!</p><p>3D Schnitt 19mm PSpan 3.dwg ... 3rd sheet 19mm particle board</p><p>3D Schnitt 19mm PSpan 4.dwg ... 4th sheet 19mm particle board</p><p>do not alter thickness of particle board as slots wouldn't fit anymore</p><p>You also need various strips of oak ... notably 9mm for keel and bilge stringers. BEWARE: these stringers acc. to class regulations (CR) must be plywood as well ... I am currently investigating with IODA if solid wood (oak in my case) would be appropriate, too.</p><p>BEWARE: for some Okume sheets commercially available density is a bit on the low side, so your hull might be 2-3 kg below limit, as may your daggerboard and rudder be, too. Cut a daggerboard, add retaining strips from oak ... if &gt;= 2kg you're fine</p><p>Have fun and keep in touch (via PN)!</p>
<p>Thanks a lot, Mike !</p>
<p>Hello from Austria,</p><p>great project, awesom description ... very well done, congratulation.</p><p>Can you please explain your reason for choosing</p><p>1) bottom thickness of 12mm vs. minimum allowed thickness of 6mmm (with 12mm thickness for the doubling pieces)</p><p>2) width of doubling pieces 280 and 80 vs. minimum allowed 180 and 70 respectively</p><p>Thanks</p><p>Mike</p>
<p>This looks alot like a Teacup sailboat which is made for the same thing, teach people how to sail. :)</p>
<p>Hey I know about the rules and laws around the moulds for fibreglass hull, but has anyone ever made one or attempted one </p>
<p>http://www.optiworld.org/epoxy.html This link has most of the same stuff as the PDF did. I can not get it to open properly either now. Between that and the British link you should have what you need to build. Good luck. Hope it is a father child project.</p>
<p>Are you coach now? Do you have realy good sailboats such as winner and another good ships&gt;? And good idea for new yachtsman :D, but i think after week they will need new light original ships. So where is no point to buy wood all parts. I think it's better to give older sailboats for new yachtsman and all costs for fixing will buy off</p>
<p>I have tried several times on several computers to get the optiworld pdf to open and it seems to be corrupted? Anyone have any alternatives. Please help/</p>
<p>wow - great work</p>
<p>Here is our fleet of Opti's we made. 2 years later they are going strong. Taught many young sailors how to sail. Taken a few hits but easy enough to repair. We added a foam fender to the bow which helps prevent damage from running into each other. I started to add pictures of a sailing class but decided not to put kids pictures on because of todays legal environment.</p>
<p>Hi </p><p>I love the instructions on the site, but I cannot download any files. It just leads me to a list of numbers. I do not have autoCAD on my computer, but would send it an architect to print it out. Can you help me with that? </p>
You should be able to download the DWG files. these would need to be opened on some type of CAD program. I use turbocad. Less capable than Auto Cad but cheaper and easier to use as well. Every automated cutting system I use reads a dwg file to convert to cut files. If you are just planning on cutting them out by hand and want full size prints to cut out you will need to take the dwg file to someone with a wide format printer. They would probably have the software to open them. Otherwise just go by the plans and lay it out by hand per the dimensions of the plans that are on the web. That is basically what the DWG files are anyway. Best of luck.
what a grate father and son project
Why waste a great racing sail and spars on a wooden boat?
3 lbs lighter in the ends than fiberglass, as in, significantly faster in chop <br>much more durable than fiberglass <br>more collision resistant than fiberglass <br>it's art. <br>
hello, long time sailor, first time building one. i am looking to build a 12-14 foot FJ/420/topaz type sailboat (2 person, mainsail and jib). any ideas? i was thinking of making it pretty much like a longer version of an opti (preferably narrower beam to length ratio than an opti though, as otherwise i would be looking at about a 6-8 foot wide boat.)
Why not go buy a used C-15. Just buying the hardware new for a boat like you described will cost probably 2x as much as a used C15 with a trailer. A friend of mine just bought a nice one off Craigslist for 600 with trailer and new sails. Needed a repair in the bow where it got T-boned but that took about $40 and 4 hours and now she has a great boat. Boat market is real soft here in the bay area. Put out a shingle on Craigslist for wanted small boat and go visit your local marinas and ask about abandon boats as well as boat storage yards for abandon boats. These Optis are so easy and inexpensive to build compared to most other boats is the only reason I would build these over buy them...Plus the fun/learning factor for the kids. Good luck...
are you suggesting i buy instead of build?!?!? you, sir are NOT WORTHY of being a member of instructables. (jk, i see the logic, but i want to have something that i built and can be proud of.)
The boat you have in mind I think is a FireBall. There are some gorgeous wood boats of that type up near the great lakes, and they are FAST.
Superdave this is a great gift you've put out there. My son and I built an opti without templates recently, I'll be NC cutting the next one for sure as we've been there and done that.
Thanks a lot
Hello from Greece. I managed to open the dxf files .do the crv and sbp files have the same content as the dxf ones.?Thank you for your reply
Those are exactly the same as the dxf files just converted to the machining files. All you should need are the dxf. Dave
Macbeath hardwoods was our source of marine plywood. <br>930 Ashby Ave. - Berkeley, CA 94710 <br>(800) 479-9907 / (510) 843-4390 <br>(510) 843-9378 fax <br>berkeley@macbeath.com <br> <br>You can stop by Half Moon bay Yacht club and see the boats for your self. M-F during the 10-3 period they are normally all sailing in kids summer camp. Great fun to watch. Rest of the time they sit on the rack next to the launch ramp.
Thanks Dave, <br>Don't know if I can make it over there during the week due to work. But I'll give it a shot. If I don't make it over during the week, I'll come over on a weekend and take a look at them out of the water on the rack. Oh, and thanks for the marine plywood source w/ contact info. That will be very helpful. <br>Best, <br>Ben
Superdave.morris, <br>I'm a longtime sailor and a new Tech Shop member in the Bay Area. I'm excited to tackle making an Optimist Dingy. I grew up sailing in Dyer Dinghys and Sunfish and I think this will be a great little boat to try my hand at for a first Tech Shop project. I'll be taking the necessary classes at the SF and Palo Alto shops to build this boat. Any advice would be much appreciated. And I'd love to come by and see the ones you made for the kids in Half Moon Bay sometime. Do they race regularly in the summer? <br>Best, <br>Ben <br>
Half Moon Bay Yacht Club is located in Princeton harbor. Monday -Friday during the day the youth sailing summer camp will normally have all the boats out sailing in front of the club.
Why can't I open the crv sbp and dxf files
I can not tell you why you can't open the files. I just checked them and the DXF files open in my cad program. I can't open the crv sbp files except on the shop bot Which has the software to do that.
So how much would one of these cost to make in it's simplest form? Like, a Home Depot budget form? <br>
We figured our cost per boat about 400. We purchased prefab sails, daggerboards and rudders due to the kids beating up the wood ones. The FRP daggerboards and rudders hold up better.
hope you get a kick out of this one. <br>
my point is to make a sail boat able to sail freely on a lake. what i want is to make a boat like this.
could you extend the frame and add a second sail.
If you did, it would in no way be an opti. Could not race in the opti class and there fore would be a one design sailboat. Which you could do. But it won't be an opti. The purpose of the instructable is to make a legal, measurable, race able opti.... <br> <br>I will add a bit to this to say we built 7 of these boats for our club. Summer youth sailing camp totally sold out and we even added 2 more weeks. Now we have an after school program going this fall. These boats have been an great addition to our sailing program. They took their fair share of bumps and hits and I think held up better than a Fiberglass one would have. You can see pictures on www.hmbyc.org.
Superdave, <br>I have sent those DXF files to a friend who has a cabinet shop with a CNC router. I will wait until your updated files to go forward. These machines can do bevels? Would a designed-in bevel on the bottom panel edges save some work?
Just added the 18 mm dxf file as well..
I just edited the instructable with the 2 revised DXF files. These change the bottom width 2mm to bring it into the center of tolerance. I would just bevel by hand. A hand planer works great and takes 3 minutes. Programing time would be more than that. At the dry fit you can see if you need to add more bevel. The revision also moves the bottom outer doublers inward and adds to groove for these in the mid frame and mast thwart. The items on the second sheet of 12 mm are for the daggerboard case sides, daggerboard and rudder. For our club boats the 12mm daggerboard and rudder are too fragile. Probably fine in a private boat. On the DXF file the size of the plywood is drawn as an outer line for reference only. Superdave.morris@gmail.com
Superdave, <br>You put the rudder and daggerboard on a file called 18mm cutsheet. According to the rules 18mm would be too thick for those items... <br> <br> The thickness of the daggerboard (excluding bevels) shall be not less than 14 mm (12mm for wooden construction) and not more than 15 mm. <br> The thickness of the rudder (excluding bevels) shall be not less than 14 mm (12 mm for wooden construction) and not more than 15 mm. <br>
And 12mm is too thin and fragile for our club boats. So the belt sander and the layers of ply for guides makes for a easy shaping of the material to end up with the desired thickness, contour and shape. You could also cut it out of a 12mm and 4mm but would require you to buy more wood. Belt sander is quick and easy. With the DXF files there you can pull any piece out of the drawings to cut it out of what ever material you like. We are actually buying the rudder/dagger board FPR combos for our club boats due to the fact that the kids run the boats aground and the dagger board takes a great deal of abuse. A private boat probably wouldn't see that abuse. <br> <br>Or run it through a planer a pass or two... And again the 12 mm version for our club wood boats is too fragile...Thanks for the critical analysis of it. Sounds like your serious. I have tweeked my drawings a little on our #6 and 7 boats. When I get the time I will post them. Change of the position of bottom doubler inward slightly, mast thwart outward 2mm and bottom 2mm wider at 1 spot. This hits the measurements a little more to middle of min and max.
You can download the official Optimist plans for free from the USA Optimist site. The International site will charge you. Go to http://usoda.org/ and click on FAQs and then Wooden Boat.
Hi , Can u tell me where did u find plans? I would like to build one boat for my kid, but your pictures are too small to use them :(
You can also find not only plans, but ready to assemble kits at http://bateau.com. as well as all the supplies needed to assemble a boat at http://boatbuildercentral.com they supply the Youth Sailing Foundation of Indian River County (Florida).
http://www.optiworld.org/Woodguide05.pdf <br><br>http://www.burcotboats.co.uk/howToBuild.pdf <br><br>Links are in the instructable as well as several others in different languages also.<br><br>You can use one of the free online drawing programs to open the different dxf files.
You're allowed to build your own Opti? (for racing?) That's SO cool. A GREAT Father/Son (or daughter) project.<br><br> Love One Design (just not a fan of One Design One Builder)<br><br>Always wanted an Opti, just so I could name it Fat Man in a Bathtub
That's a gorgeous little watercraft, it reminds me of my very first boat except the &quot;pram&quot; had a small deck and a removable seat over the dagger board well for rowing. Very nicely laid out &quot;ible&quot; thank you for sharing
I built an 8' pram very similar to this in 1961 at the age of 13 with ZERO help from anyone once I had the supplies. Paid for the whole thing myself with my paper route. Sent away for plans I saw in the newspaper or a magazine. <br><br>I built it as a rowboat to use on Lake Erie, about 500' north of my house. The hull is curved and the whole thing is a bit more graceful. With one person onboard, it moves pretty good! Had a few scary times in Lake Erie, but survived them all! Very interesting ride with two folks and whitecaps.<br><br>I still have it and last used it about 15-20 years ago at Kelleys Island when my kids were smaller. Now I might have to take it out of mothballs and give it another summer. Sucker is going to be 51 years old in a couple months!<br><br>Thanks for the great article!
Great job on the instructions. Looks like a fun boat for the kids. Is there a bigger version for big kids (adults).

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