Low-speed sailboat hull

I am right about you getting all caught up in CP and Naca sections, when you have a lot bigger problems than that.

Yeah - thats why I said waaaay back - buy the plans and substitute materials to suit !!!!

The money for the plans is worth it just for the dimensions and patterns. You have to reconcile yourself substituting specified material.

 

Stability is usually the problem with small boats. It is always easy to fit a bigger rig for more power in lightwinds. What you need is an efficient hull at higher winds/boatspeeds, a time when staibility or sail carrying power is usually limited. Furthermore, small boats are often uncomfortable to sail in very light winds, so check that feature out when you decide on a design.

You might be interested in my 10ft Tryst trimaran, or Duo dinghy. We are travelling round the USA with a Tryst in the back of our pickup truck. The mainhull nests, so fits in a 6ft bed and the whle boat built from just three sheets of plywood ( two at 4mm for the main hull, one at 3mm for both outriggers) so is very light

We were at SailOK in Oklahoma last week, unfortunately in the end Dave Gentry couldn't be there so we couldn't compare boats.

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Looks like a great design. Might be a bit ambitious for the OP, but a good small boat solution

http://www.sailingcatamarans.com/index.php/designs/27-trimarans-under-25/428-tryst-trimaran

 

Thank you for the compliment. We did build a basic Duo in two days

http://www.sailingcatamarans.com/in...-dinghies-/431-edensaw-boatbuilding-challenge

After 2 hours it looked like a boat (see the first photo), which is always encouraging for new builders. The sailing, nesting and trimaran versions are all options, and all can be done at a later date after the basic boat is finished. Unlike the Duo most 2 sheet plywood boats have no built in buoyancy, which to my mind makes them dangerous

We have our Duo/Tryst in the back of our pickup right now, somewhere, it is hard to see as we have clothes for a month of travelling, food, cooking stuff, boat parts to sell etc in there as well

Richard Woods

 

All right. Sorry if my focus on these things look silly. I'll contact Dave Gentry on details on Annabelle before ordering.

Thank you, but that looks a bit out of my reach as of now. Maybe sometime in the future, though - I'll keep that in mind




Well, I think I gathered enough information. Thank you everybody, especially rwatson, for getting me on the right track, and providing so many options to choose from

 

Hello again,

I'm sorry, but have to re-address you again, because the more I look, the more it seems that I'll be unable to build SOF Annabelle. There are no manufacturers in Europe that I can find who would sell uncoated 8oz polyester in small quantities. Nylon cannot be heat-shrunk enough to accommodate the rocker of anything but a kayak, and canvas will make the boat overweight.

I'm still searching, but I doubt there is anything in Europe. And shipping from States will cost more than fabric itself.


So, my question: does anybody know of any non-SOF designs of car-toppable 3-4m sailboat for 2 persons, weighting under 30kg, spacy enough for whole day cruise, generous sail area, build-able under 1000$?

Oh, and by the way, marine plywood is also not available in my country. I asked local boatbuilders. This just keeps getting better and better...

 

It's really difficult to built a sailing dinghy < 30kg. You will need non-standard materials.

Options.
1) Inflatable sailing catamaran. < 30 kg, but they are expensive
2) Standard car-toppale sailing dinghy. ~ 40..45kg $1000 ... $ 2000 for a second-hand dinghy and you don't need to build anything

 

Thanks, but I'm now looking at monohulls only. And 1000$ is absolute limit.

 

Is the small weight really important? My dinghy is 45kg fully assembled and I think it's OK to transport this dinghy on a roofrack of a car.

 

Sorry, but yeah. My car has a roof rack limit of 35kg. It is illegal to put on more (they actually fine people for this where I live).

Also, I need to be able to take this boat, carry, and put on the roof single handed.

 

Yes, your specifications are really challenging.

Have a look at "MATCH 4" Extremely small boat. I'm not sure whether it can accomodate 2 adults (the photos show 2 children). And it is 36kg assembled. http://www.bellamer.com/_e/match.shtml

 

Thanks, but it is too heavy, fiberglass cloth is not available in my country, and I somehow doubt it would fit the budget anyway...

Are there really no stich-and-glue designs that would fit the criteria? Using thinner plywood, perhaps?

 

Any nylon or polyester fabric would work for SOF, I have used nylon, polyester, cotton, and even nomex (got a big roll of it surplus cheap). it does not have to be raw, or untreated, it is best if it is uncoated, but I have used surplus fabric that even had a print pattern on it (that got painted over anyway).

You just have to get creative on the design to make it wrap over the shapes. you can put seams or darts in it, if done carefully, to make it fit complex shapes. You can for example put a seam down the keel line, and than put a wood rub strip over the seam to hold it and protect it from wear.

Built two sof kayaks (weight about 20 lb each), and than have light and hollow beams you lash between the kayaks to make a catamaran, with a trampoline deck that is laced to the beams. if built carefully it the whole boat and rig should not weith more than about 30 kg (about 66 lb). short hollow mast, Tyvek junk rig sail. Simple to set up, light and it all can be built with local lumber (no plywood), and what ever fabric you can find. All lashed frame, with perhaps 6 or 10 dowel joints, no need for any metal fasteners. I can build something like this for about $300 buying everything I need retail (even less if I can get much of it salvage), and it all breaks down to the size of the kayaks (non folding), the mast and beams. the beams, mast and rudders can be designed for fitting inside the kayak hulls at about 8 or 10 ft max each.

The kayak hulls would be 16 ft long, tramping deck would be about 6' x8', with the kayak hulls for gear storage. Pull the cock pit covers off the kayaks and unlash them from the beams and use them for local shallows. everything can be assembled without tools.

You can build a 14 ft x 5 dingy, it will weight more, have less room, cost more, and not be as stable, nor as useful.

Take your choice.

 

Okay, you have a 35kg roof limit. But what has to go on the roof? Not the sails. Not the dagger board or rudder or tiller. Not any removeable seats or thwarts or cushions or floorboards. Basically just the hull and spars. You can almost manage an RS Tera on that weight budget. The Snarks are easily within your weight budget at 12' and can some can carry 400 pounds. I think with a bit of effort, you could get a 13'er to go. There was a very nice cartoppable 12'er that had lines by a Herreshoff. One served as a dingy for a friend's small liveaboard. You might find lines for that one.

Frankly, I can't imagine getting a ticket for anything that didn't look ridiculous. I managed to carry three 21' canoes on an old civic, but I had really good roofracks that spanned 8'. Surely people carry couches and mattresses around on their roofracks in Lithuania? I mean its not like you were trying to carry a herd of cattle in it -
http://newsbite.it/index-id-weird news-zk-18878.html

 

I would add my support for Petros comments.

I dont know what you mean by canvas - but you seem to be thinking of the heavy truck covers.

Go to some fabric shops, and look for really lightweight materials. You can waterproof them with a variety of cheap 'paint' products.

On the Annabelle thread, you got good advice about low cost, fabric backing alternatives for bent sections.

I understand you are still fairly new to boatbuilding, so these alternatives wont be obvious at the start. I recommend you go and buy small samples of things that may be useful, and have a 'play' with them to get a feel for there capabilities.

You will be surprised how solid a hull you can create from really inexpensive materials. Heck, you could make a great lightweight hull from papier-mache if you want to spend the time. The first thing is to get a proven shape to work to, and then all the effort and experimentation will be towards a worthwhile end.