Building a cheap sail catamaran
Vložit
- čas přidán 2. 08. 2019
- (↓↓↓BASIC CALCULATIONS BELOW ↓↓↓)
A short video (including pictures) of the building progress on my small 12' sail cat, almost entirely built with cheap construction materials and with relatively few tools. The whole build lasted 3 weeks and costed about 500 US$. I didn't use any plans, but only relied on a few basic calculations kindly provided by my friend Dario.
Below are the basic calculations I did. Unfortunately I don't have much more... I built it a few months ago, at my dad's home, and can't access it at the moment. You can get most info through the video and estimate dimensions.
Note that with these dimensions (the mast has about 5.2m, the boom 1.8 meters, the hulls 4m long, about 60 cm deep and about 50 cm wide) the flotation is just enough for one 80kg person, and even so, the deck gets very wet. Deeper and possibly wider hulls would be better, although to make it faster, longer rather than wider hulls would be preferable. The sails are small, and perform well only in relatively strong winds, thus I suggest a longer mast if you can, or a longer boom (in case of a longer boat) depending on the average winds you have in your region (also, you can use a much thinner beam for the boom, like the "stick" I used for my bowsprit. The 2"X4" beam I used is way to heavy). I have a total sail area of about 10 sq. meters, which really isn't much in light winds. The mast stays are made of nylon on my cat, however I strongly recommend steel stays, especially with a skinny mast like mine (4cm X 8cm X 5.2m) since it bends a lot in strong winds.
My wooden deck is maybe pretty, however it's as heavy as both hulls combined(!!!). You can try to make it with 1/4" plywood, and add a few small structural beams under it, to lighten the boat.
Because of the very sharp hulls profile, I don't need any keels or centerboards to keep the boat in a straight line. However, like on monohulls with very long keels, tacking the boat is tricky since it won't turn around so fast, and the lightweight construction means the boat will stop immediately once you get into the irons and the sails lose all power. In my case, I use a paddle to help the boat tack around or either simply jibe (although when going upwind, jibing is very inefficient). - Jak na to + styl
Hi! Very cool! How to sew sail and not make them flat?
I made each sail of three horizontal strips sewed together (most fabric rolls are 60" wide). For each piece I cut the top and/or bottom in a rounded concave shape so that at the center, the edge sticks out by 2 to 3 inches (for a 15' tall sail. For larger sails the edge needs to stick out more). For the bottom piece only the top is rounded and for the top piece only the bottom is rounded (in other words, only joining edges are rounded). When you sew them, sew along the edge as usual, and your sail will have a bulging shape!
For large light-wind sails like a gennaker or even a genoa, you can make the edge stick out more to give it a balloon-like shape as it will be more performant going downwind, especially with lighter winds.
I might draw some plans and put them on a website if there is interest, although I am an amateur and completely uneducated and unexperienced about boat-building.
@@FedericoLucchi thank you, gracias!
Can I have the plans? I liked build.
I've watched this so many times my wife starts freaking out if she hears the soundtrack playing and its become a big problem in the house
Hahaha! Apologies for any household inconveniences! Each pontoon is 12 feet long (about 4 meters)
What a great job you have accomplished
como también quiero construir una embarcación, miro mucho y lo que tu has hecho es de lo mejor que he visto. simple, sencillo, pero apasionado y funcional. Gracias por enseñarlo.
Muchas gracias! (that's as far as my Spanish goes, unfortunately) Very happy that you liked it, indeed I tried to keep it as simple as possible. If you try a similar build I strongly suggest to aim for a taller mast and a longer boom in order to increase the sail surface (mine is too small for light winds). You can have a much longer boom by removing the backstay, bringing the shrouds a little aft of the mast and using longer spreaders (and steel wire, not rope). On a small craft like this, it's not too hard to make a strong rigging.
Also, don't hesitate to go for larger hulls, my cat's buoyancy is barely enough for two adults.
Good luck with your project!
Great job young man !
That is awsome .Very cheap but great satisfaction with it
Indeed it really is! Some people take these builds too seriously and forget that it's all about learning and, most importantly, having fun.
very nice! I'm using your idea for the hulls to build a small model that is 60cm long. Using fiberglass and waterproof wood glue.
I also first used the concept to build a model. Just used thick paper and glue, worked quite well!
If the material is flexible enough, ideally try to make the hull as fat as possible. Towards the middle of the hull, the top should be as wide as the sides (the profile should thus be an equilateral triangle at that section). This will give it better floating. If you plan to make it an RC model, this fatter hull will allow for center boards, which in turn will allow for easier and faster tacks.
@@FedericoLucchi I made some prototypes over the weekend, but am going to scrap those and rebuild with a different method. The thin plywood I used delaminated under stress, so I will be using thin internal strips for the keel and bow with them being held together by glued in dowells. I will also waterproof them before assembly to minimize the weight of waterproofing caulking required. Thanks for your reply and information about the dimensions! :)
No problem! Good luck with your build!
I'm thinking of making my own catamaran with heavy-duty tarps as "skin" for each hull and compartments filled in with water sealed jugs or barrels.
As long as it floats, anything goes! It should work fine if you row or have an outboard engine, however for using a sail a better profiled hull will make things much more pleasant. Although a raft can be sailed too... (almost strictly downwind though)
Excellent ! Looks great... This may be my inspired design.. Thank you Federico..
Cheers! If you build a boat, the golden rule is to keep it simple.
@@FedericoLucchi Will do..
Very good catamaran!!!
genius plug design
not bad for a 1st build. you'll do even better on the next one
Thank you! Of course, in future builds I will already know what needs more attention
How about next one ? catamaran .. I've been working on an idea for 3 years now... thanks. What about when there's no wind ?
I'm currently abroad, as soon as I move back to Canada (the cat's location) I will work on improving it further.
Well, the whole idea of sailboats is to use wind... with a boat as light as a small cat you have however the option of rowing (although the width of the cat makes it hard for a single rower), or you could bring along a small outboard engine, electric would probably work fine too.
hi from Auckland New Zealand
Hi! Sailing in New Zealand is my dream!!
Very cool thanks for sharing subscribed
Applying a coat of spray on Lanolin will reduce Drag Up to 20%
Thanks for the suggestion. Although I need to improve the rig first, I think lanolin spraying of the hulls (like waxing surfboards) makes sense at higher speeds when water friction can indeed become an issue.
i hope you spend more time looking at cat construction my dude, that was a good first shot and you've identified a lot of things already that will continue your improvement, look here on YT and reach out in person to ship wrights and boat builders all over, they're out there . . .and 99.9% of them LOVE sharing their knowledge and lending a hand, especially when younger folks show interest . . . beyond that keep it up!
I will definitely work more on it in the future! This was a first and built to be used on a lake, not sea or ocean, thus the challenge wasn't that high ;)
@@FedericoLucchi hehe don't be like that :) you did phenomenal so much so you got a whole bunch of armchair quarterbacks and old men alike to get excited and engage with you about it, 150% success in both the build/sail and documentation/share of that whole experience :) it was an absolute joy to watch and i know i can't wait to see where this adventure takes you :) good luck, great water and steady wind my friend!
Very important to make the inside very waterproof, ie coat with resin. Then have a good sized vent at the bow and stern. Otherwise she will rot in time.
Can I have plans? I liked build.
Michaelangelo In the making
That's probably an overstatement ;)
Can I use a gunter rig on a home built catamaran? It has shorter mast and cheaper , easier to make it .
Of course, there are no rules about what you can and can't do. Thor Heyerdahl crossed the pacific on a square-rigged balsa raft. Of course each rigging has different advantages, but for a home-made practical project a Gunter rig should be perfect. Note that if it's a small cat, a Marconi rig is actually no big trouble to build.
Check out designs by James wharram for similar design and construction. Note the smallest Hobie or Wharram is 14’ long
LovelyLovelyLovely!...& motivating! Thanks!
Nice Build , better than spend 2000$ for a sailboat only to find out you don't use it enough . Looks like it would fit in a garage on it's side and still leave enough room for a small car.
Yes indeed, I bolted the hulls to the structure, so it can easily be taken apart and stored for winter (or whatever period you don't plan to use it). Also, it was even more fun building it than sailing it. It would still need a few more mods to sail better, like steel mast stays instead of nylon, but I'll tackle those next time I visit my dad's home (that's where it's staying).
Very impressed. Can you put your plans online?
Unfortunately I didn't do any proper plans, just put everything together step by step adjusting as I went along. In the video description you will however find all the basic calculations and observations I made during the build. If you wish to build a cat from scratch yourself, they should be fairly helpful.
Hello ! Well done. Do you know if you are allowed to sail in let,s say Meditteranean Sea with this type of self build catamaran? Thank you
Laws change from country to country, but generally a small boat without engine is unregulated, which means you can do whatever you want. Of course, you need to make sure your boat is seaworthy. This cat's rigging and structure probably wouldn't survive a proper Mediterranean breeze for too long...
Cool but you really need dagger boards. I could you oversteering to compensate.
The profile of the two hulls is actually too aggressive, making it handle much like a "long-keeler" (hard to do a quick tack). The "oversteering" you appear to have noticed on the video might be caused by an unbalanced sail surface (a larger main should do the trick), although while sailing I never noticed it...
Paesano! Molto bene! Hai risparmiato un sacco di soldi. That means "Buddy, very good! You saved a ton of cash" in case you are one of those 3rd+ generation Italians. I got time and lots of free wood, so I'm gonna try. Except I'm going for a 28' length and taller hulls. If I succeed I'll message you.
Sono cresciuto in Canada ma nato in Trentino! ;-) Bravo! Anch'io sogno di fare qualcosa di un po' più grandino.... ma per l'istante vivo in città e non va. Buon'idea di fare i scafi più profondi (mi sono venuti così perché ho tagliato l'asse in metà, e non volevo comprare due volte più materiale), sopratutto se come me (per ragioni di semplicità e solidità) fai il ponte al stesso livello dei scafi. Ti consiglio pure di utilizzare cavi d'acciaio per i "stays", il nylon è troppo flessibile e l'albero si piega un po' troppo quando risalgo il vento.
Buona fortuna, e tienimi al corrente!!
Sono cresciuto in Canada ma nato in Trentino! ;-) Bravo! Anch'io sogno di fare qualcosa di un po' più grandino.... ma per l'istante vivo in città e non va. Buon'idea di fare i scafi più profondi (mi sono venuti così perché ho tagliato l'asse in metà, e non volevo comprare due volte più materiale), sopratutto se come me (per ragioni di semplicità e solidità) fai il ponte al stesso livello dei scafi. Ti consiglio pure di utilizzare cavi d'acciaio per i "stays", il nylon è troppo flessibile e l'albero si piega un po' troppo quando risalgo il vento.
Buona fortuna, e tienimi al corrente!!
Bravo Federico¡¡¡¡¡¡¡¡
Супер🎉🎉🎉
Hi Federico, I'm re-assembling an old cat and need to make rudders for it, How did you made yours?
Rudders are very simple. If you don't need a "pull-up" mechanism for shallow waters, all you need is some plywood to cut the rudders in, some stainless door hinges (unless you have a better option of course), and make sure both rudders are linked so they're always parallel. In this case I used fiberglass rods and some rubber tubing for the links (you can see it in my video)
Very nice. :))
Hello,
That is a very cool build !
Could you please tell me how thick was the plywood you used ?
The initial 4 Sheets of plywood you cut, were they just rectangular ? or did they have any special shape to it ?
The Plywood profiles - what was your way of calculating the sizes ? thank you -
The large sheets (for the outside of the hulls) are the thinnest I could find (3/16"), and yes, they are just rectangular. You could use 1/4" too of course, it would be stronger but a little heavier too, and maybe harder to bend in shape. For the profiles I simply designed triangles (with the sides rounded), starting thinner from the bow to wider at the stern. I just used trial and error, cutting it a little wider, trying to fit it, than removing material where needed.
Once you have the hull sides glued together with fiberglass on the bottom and front, it's easy to "open them" and see what shape they naturally take, and from there you just design the profiles the way you think best. I used just a few profiles and the hulls turned out very stiff, and amazingly light. I can carry around a single hull by myself, no trouble at all. The heavier part of my boat is actually the wooden deck (it's as heavy as both hulls combined!!!!). If you can do something with aluminum tubing maybe or 1/4" plywood instead of thick planks like I did, it could be much lighter and thus perform better.
I first made a simple calculation to make sure that my design would have enough buoyancy. As it turns out, I have just enough buoyancy to sail safely for one adult. Unless you can make a very light deck and boom/mast, I suggest you try to make the hulls either longer, deeper or wider (making them longer might be the best option for speed).
@@FedericoLucchi. Or to give more buoyancy, add a flat bottom, ie dory shaped. This will increase the load carrying with the least increase in weight.
Check out the designs by James wharram for similar design and construction ideas
Belo projeto ...parabens quais as medidas poderia me passar?...obrigado
No problem. I plan to put the material on a website in March, but if you want just give me your email and I’ll send you what I have right away
@@FedericoLucchi luismarchini@hotmail.com Thanks
it looks like a 'patin catalan'
How long did you make each pontoon?
Each pontoon is 12 feet long (4 meters)
@@FedericoLucchi Thank you!! This is super cool
can you say all of your measurements and your build plans please
Hello there! Unfortunately I didn't do any plans and the cat lies at my dad's home at the moment, so I can't take any measurements... in the video description you will find all the notes and measurements I took during the build! If you have any particular question, let me know!
Looks very similar to the El Gato design cat from Glen-L boats. I believe this was also printed in either a popular science, or pop mechanic magazine back in the day. anyway ...great effort and appreciate the video.
If you laid a polytarp o er the net it would be much lighter.
How much did it cost to make
I know it's been two years 😂
@@oisinorc3007 Haha no problem! It costed me a little less than 1000$ CAD (about 800 USD), but it depends a lot on the materials. The sails, hulls, deck and mast costed next to nothing (just the fabric, wood, glue, fiberglass and paint), but I spent a bit on the various pulleys and ropes for the rigging because I bought everything in store... next time I'll have a better look at eBay/Amazon/Taobao, I can definitely save a lot more money.
Panjang dan lebar berapa meter om
All dimensions are given in the video description :)
Make a 30 footer! 😁
I would probably need to revisit the design, this simple construction process works a bit like a "monocoque", and I think it would be very difficult to build with a thicker and tougher plywood
@@FedericoLucchi Make it flat bottom. Tech Ingredients is a science CZcams channel. They made a little catamaran. Super simple design that seems scalable. Harryproa mini cargo is another good design to look into. I'd like to see someone build an ocean worthy cat for cheap! I'll help build it if I'm close enough 🙂
Cool
The Plans Price?
No price! I didn't really draw precise plans, but if you're interested I can send you the info and basic calculations I did for the build
@@FedericoLucchi, could you send me the info and basic calculations? Please to roberduarte@gmail.com Thanks...
@@robertoduarte9917 OK I will as soon as possible!
Goocipdotcom@gmail.com
Maman Agustin Sent! :)
Looks like it might last one summer and sail badly
Thank you for the constructive criticism, can't thank you enough for how helpful it is!
It did live only one summer so far, but survived the rugged winter fine, so I don't worry too much. A new coat of paint isn't that much trouble anyway. As for the sailing, it doesn't handle like an America's Cup cat, but it gave me many hours of fun, and isn't that all that matters?
@@FedericoLucchi You rock bro! Made me smile. I'm looking at making my own cat but I'm going full carbon. This inspired me to just get started. You really can make a sail boat out of the most basic materials. Love this vid!
@@HighDefinitionVideo Thanks for the comment! Full carbon will be insane!! Using home-hardware wood, I could lift my whole cat on my back (without the rigging), can't imagine how light you can make yours!! People nowadays forget that sailboats exist since thousands of year. 60 years ago, there were still Vietnamese and Chinese junks made of bamboo and smeared with cow dung (for impermeability) that could carry 5 tons of merchandise.
@@FedericoLucchi Federico, Are you new to the web? That was a troll comment. You are supposed to ignore them!
I'm not new... rather too old. And sometimes I just like to troll back. ;)