DIY sailboat that can be carried on car roof

Hello everyone I just found this website and it's full of useful information and kind people, so I thought I could ask here something that I am trying to work out.
I recently found out about this category of DIY boats made out of plastic drums, and I really want to make one. In particular I would love to be able to rig it with a sail and have fun on small lakes and calm rivers around my house.
My first thought was that, since I'm somewhat experienced with canoes and kayaks, if I was able to produce a canoe like the picture attached, I could have been able to fit a sail as well by adding a wooden supports for a mast, either in the center or in the front of the boat. But some people disagree with me and said that a canoe shaped boat like this will topple and it's not good enough for my project.

I'm at a loss now on what to do, I have all the materials required to make this kind of boat but I'm unsure of the shape I should give it. My main requirement is that the boat can't be wider than 1meter at the center, because otherwise it would not fit on the car roof. My previous plan was to make it 3mt long and 1 meter wide!

What do you all think about this?

 

Based on considerable experience with homemade, home designed Kayaks, don't worry about a 1 metre width limit. That is quite wide enough for the average canoe.
The SHAPE of the hull is what is more significant
https://wenonah.com/Canoe-Design.aspx

Lookup some typical canoe designs, and use their dimensions as a useful guide. eg.


Considerations When Buying a Canoe - Frontenac Outfitters Canoe and Kayak Centre https://www.frontenacoutfitters.com/blogs/tutorials/considerations-when-buying-a-canoe

Two immediate thoughts on your particular project
1)
I cant think of a more miserable material to build from than plastic drums. Especially for a 3 metre canoe.
The hull profile you will be forced to adopt will really, really "tender", and prone to capsize unless fully loaded, and the idea of sailing the thing means you would need a wetsuit and lots of practice.

In my impoverished youth, I spent years trying to build canoes out of scrap and cheap hardware, and while it kept me out of other troubles perhaps, it was ultimately a just a waste of time.
I didn't have the luxury of hundreds of YouTube Videos to show how it was done.

I cannot emphasize the sheer efficiency and ultimate satisfaction of building a design from an experienced designer, be it Plywood, Canvas, Strip Plank, Papier Mache, Fibreglass or Foams.

2)
Sailing Canoes are either super specialist designs for the keen power sailor, or life threatening roulette activities for the brave and foolhardy. Don't expect a gliding bliss of calm water and gentle breezes.
Especially in a shallow arch plastic hull. I have a number of personal articles rusting away at the bottom of a certain estuary, compliments of sudden gusts.

I've no doubt you will get lots of other good advice.

This video may give you some interesting ideas of the ups and downs of canoe life. Have fun.

 

Many many thanks for your reply, it was super helpful especially the links you provided!

 

Hi Spear95, since you're a canoe fan, how about a couple of canoes that nest, and some cross beams to make a catamaran of them; or a ballasted sailing canoe. A Mirror dinghy was designed to be car topped, and sail with a small crew or single handed. See a post just below further in the forum. It's designed to be home built, and is a versatile boat; a bit wider than a metre, - how small is your car roof ? A boat made of plastic drums would be heavy, and just awful no matter how good a job you did of it. There are some interesting inflatable boats for sailing, including catamarans.

 

Is 1m wide really your limit ? Because with say ~ 1,30 m you can have a real sailing dinghy if it is your core programme, not just a canoe with sail. Here is an example, Velocette, a nesting dinghy but which can be build one piece (here in strip-planking+ glassing) . L 3,60 m x B 1,31 m x ~ 45 kg bare hull x S 5,6 m2 , and you can put it on top of a small car like a Fiat 500 :


All more details on this dinghy project within the link here below + some videos :
Velocette : a nesting dinghy for fun sailing | Boat Design Net
Videos :
(10) Facebook
Velocette sailing in 8 to 10 knots of wind - YouTube
Another clip of Velocette in Tyrrel Bay - YouTube

 

You might be able to use a tilted roof rack to carry wider single or parted catamaran Hulls..

5 Best Double Kayak Roof Racks: In-Detail Reviews (Summer 2024) https://rackadvisor.org/double-kayak-roof-racks?msclkid=f8235a0578681539488d3cb0d98e54d0

Why build a boat hull, when used junkyard kayak, canoe, catamaran and other small boats are so cheap? Sometimes they are given away because we have such a surplus of those in the usa. But maybe you don't have that situation in Italy?

 

Hello everyone and thanks for all the answers!

First I want to say that my 1mt limit was set because I really have crappy roof bars on my car, but after looking at small boats for sale I understood that my best bet is to either buy or build a dinghy rather than a canoe. As seasquirt and Dolfiman pointed out it's still an option to carry it on my roof but there is more space to be comfortable in and it should sail better.

Unfortunately junkyard kayaks are not a thing here, otherwise I would gladly take them and use them for my project. People would rather sell you boats with holes on the hull for full price rather than give them away, so many boats are rotting in someone's garden at the moment. Funny thing is that for bigger boats, let's say 30 feet sailboats, you can really get them for ridicously cheap. A guy near me is trying to sell his "old" yacht for half the price of my car!

I found someone on a "sell used stuff" site that maybe is willing to part from an FJ for cheap. He is also selling a laser but the mast is too long for my car to carry legally so I can't.

I want to build a boat hull anyway with all the stuff I have, maybe it will teach me something valuable!

 

I can see that this dinghy is really awesome, I downloaded the PDF file and I looked at your process, really an awesome build! I was wondering if I could ask you a couple of things about the process, I am a newbie and I dont' understand how big these pieces you used as a template are. This would be really helpful for me to start redesigning my hull, because I was going for a completely different shape! See pictures below.

As of now I bought the new bars for my car, so that I can have more room and I can now fit a dinghy instead of just a canoe!

 

Thanks for your kind words about Velocette. Actually, as it is explained in the pdf, it is Russ Whitford (« VeloceRuss » within Boatdesign forum) who specified the programme, imagined the structure inc. the nesting arrangement, built it and of course at the end sailed with it. My role was to help him with design propositions for the hull lines, the computation of the hydrostatics, the mast position. So for the building process, and if you are also oriented on a strip planking + glassing solution, you can contact him directly with a personal message (see « Conversations » in your profile page). In particular for your question, within his sailblog he described his process for the template jig, here :

Tumultuous Uproar (sailblogs.com)

I can just mention that the core structure was made of Th ¼'' (6,35 mm) Red Cedar planks on Th ½'' (12,7 mm) Ply frames (which stay part of the stucture) + molds (which are removed after the strip planking and external glassing). And that Russ mostly relied on Nick Shade book « Building strip-planked boats ».



As regard the hull lines, I can propose you a starting point very close to Velocette in dimensions, shape and design displacement, still adapted for a strip planking building (i.e. not a multi panels shape) but with a bit more free board in the fore half, as this part is no longer necessary to store inside the aft part as it is for the nesting version, and also without the hard chine in the aft half part which is a bit complicated to build. I called it « Dolfi 12 IL » (like Italian Lakes ) , designed with my application Gene-Hull Dinghy here attached (with the Dolfi 12 IL data in place), that you can open and use with Open Office or Libre Office (to note that my application cannot presently deal with multi chine hull shape). Also attached a pdf to introduce the Dolfi 12 IL + the pdf of the application User guide. With of bit of practice of the application, you should be able to adapt this preliminary design to your exact objective. And at any moment, you can recover the offsets of the hull in the dedicated sheet « Offsets x, y, z ».

 

Many many thanks for your kind help! I just came back home and I will check out the excel datasheet to make plans for the DIY dinghy!

 

Thank you all for your kind replies, after remodeling the whole project to have a similar shape to the Dolfi 12 IL, I tried to build it with those plastic drums but I had disastrous results. Unfortunately the material itself doesn't bend as I wanted it to, making it really hard for a single person to work on it. It's a three men job and the result is sloppy anyway, so I decided to scrap it all and go with wood!

In the end I decided to buy some plans with all the measurements carefully laid out, once I can buy all the materials I will start to make my own dinghy!

 

Canoe Sailing - ACA https://americancanoe.org/competition/teams/recognized-disciplines/canoe-sailing/
Uffa Fox - "Sailing Boats" - International Canoe https://intcanoe.org/en/dca_uffa_sailing_boats.php

 

Thank you for reporting the outcome of your experiment,it may save a lot of wasted effort by the next guy with a desire to try something different and move him on to a potentially better way to get afloat.You can't really describe it as a disaster as something was learned and nobody got wet unexpectedly.

 

Yup.
Hence my original observation "I cant think of a more miserable material to build from than plastic drums. Especially for a 3 metre canoe."

 

Yeah I think this conversation can be helpful to others as well.
A couple details I want to add:
First of all, I think a lightweight small canoe is still a doable project. It's just not as easy as seen on videos such as this:


My idea tho was to build a more complicated design such as this one, to fit a couple seats and a sail with more ease:


I was able to build all the wood parts required with ease, but when it came down to assembly I understood why they had to make it as big as you see in this video: the plastic is just not bendable enough to adhere to the stem in the correct position. You either need to make the boat longer or narrower, so that the plastic sheets will not bend as much in different directions. That's the reason why all the videos such as these either show open canoes or long motored boats; to make a sailing dinghy out of these materials is too hard.
You could in theory cut the plastic in strips and use them as you would for a clinker boat, but at that point you run into problems that wood doesn't have. Plastic is only good if you can keep it in one piece and bend it at will. Something I'm clearly not good at!

Wood is way easier to work with, I'll stick to that. The only issue I have with it is that it's pricey, but at least my boat will look awesome and will be much safer to sail!