Where to start?

Scaling up is a no no. It can be done, but it's not a proportional type of thing. I know this seems counter intuitive, but it is the case.

The more effort in assembling and disassembling a boat, just to house, store or other wise handle it, the less likely it will be used and the more likely you'll have issues with the "joints" which would likely be solid connections on a more convention arrangement.

High performance boats can hurt you. It's not the getting dumped part, it's the path your hat holder takes to it's eventual place along side the boat. I've got some nasty scars from a capsize in a radical planning dinghy. The main sheet tackle, wrapped around my neck as I went through the rigging. These scars are 20 years old and it looks like I was bitten by a shark. A healthy clunk on your head can render you helpless at a point when you truly need full capacity (like remembering not to inhale while under water and other simple stuff you can't while unconscious). Trust me, step up to the hot rods, accept the intermediate boat as a tool to gain the abilities necessary to get your butt kicked in a hot rod.

 

Richard,

My "test drive" comment wasn't to actually launch the boat, but to see what shape the hull gives.

Scaling: I would have thought that the same formulas which are used to make a scale proof-of-concept model could be used for adjusting the size of the sailboat. Of course you would need stronger materials in some places.

Thanks.

 

Par,

I didn't see your post.

Scaling: More than recalculating the strength of beams, etc? I have a book that helps you convert the forces and all that for an as realistic as possible model.

Assembling/disassembling: I don't know that I would continually do it, but since my house is in an area where things like that can't be stored outside I would like to be able to do it should some official looking person come sniffing around. There are a few boats hiding around in the area, so I don't think it would be a problem. However it would be a bad thing to be caught with a boat I can't put inside at all, as opposed to one that I could break down should I need to.

High/medium performance: I'm not arguing with you here, but maybe don't have a frame of reference. By the fact that you keep bringing it up, I assume that Alexa's Rocket is a high performance boat? Say so, and I'll back off on that one. How do I tell what's a hot rod and what's a moderate boat? I just don't want a slowpoke.

The 420'er that I was in was a lot of fun. I don't know how fast it was, I can guess at power boat speeds but not a sailboat. It would be good to get into something that fast or a bit faster. I think the boats we were using at Northwestern were rigged fairly moderately, given that they were school boats.

The vast majority of the posts here seem to be aimed at wood construction. I'm not talking so much about this thread but more at the forum in general. Is there something I'm missing here? Wood boats are considerably heavier than a core boat would be, right?

 

I understood you right with the "test", but that is a very weak and wobbly thingy before its "glued". The easier way to test a shape is to make a >>scaled<< version in cardboard!:idea:
And as Paul and I mentioned it really is not possible to scale a ship up or down and keeping his designed abilities. For a model of developable hulls naturally thats possible.
If it comes to tank test models, they are not just "scaled", they are engineered to scale!:idea:

The cored boats are not per se lighter than a good wooden design, it is often found to be the opposite. This is especially the case in terms of homebuilding.
The reasons why you find so many wooden projects here are pretty simple, it is the material with the best overall performance and the least overall skills needed. It is light, cheap, available and nearly everyone who thinks about doing something by himself has some skills and experience with wooden constructions. Maybe just a selfmade bookshelve. And usually some of the tools are already found at home.

I would like to recommend very much a strip planked boat as your first (well not really) project. The lighter designs use the strip as the inner core between glass epoxy layers, giving a very rigid, durable and stable structure, wich is to beat by highest - tech carbon (and the like) composite only!

The "420" class is a fast boat, yes but I would´nt call it a hot rod. But it is truly not a boat for some puttering around, it shows its performance by use of a trapez for example.

Regards
Richard
and I´m so glad to have PAR correcting, replenishing, resuming my statements. Thanks Paul.

 

Ken, this site has a wealth of info, 100s of plans, books on how to, a history
of past info and a great forum of hands on builders. It will take you a while to view it thoroughly. Great customer photo section. Geared more to wood than composites but a great site no matter. I built my first boat with their plans, the flying saucer, in 1958/59 they have been around awhile. Glen L Witt is a N.A. as is Ken Hankinson. All great people there. Stan
http://www.google.com/search?source...lz=1T4GGLR_enUS202US205&q=glen L boat designs

 

In the size you're looking to build, materials other then wood, will be hard pressed to stay as low as wood in weight, without turning to fairly exotic techniques and materials.

No, scaling up a boat isn't as simple as recalculating loads for structural elements. Stability, balance, beam/length ratios and a good bit of stuff you're not too familiar with all change, some quite radically with scaling attempts.

The 420 is a good boat, though I'd like to see you learn sailing skills in something more forgiving initially.

This might be just the ticket, buy a cheap, well used boat to learn some skills in, then build your performance oriented boat in the mean time. When finished, you should have enough ability to expect reasonable success in a low end hot rod.

I don't recommend high end performance craft for any one other then well seasoned sailors. There are many reasons for this, but some of them are: They can be highly costly to own. A set of good laminated sails will set you back some fairly big bucks and you'll be lucky to get a couple of seasons out of them, before they're stretched out to bags. The cost of rigging these highly strung rockets is equally pricey. They aren't relaxing to sail, usually the opposite and twitchy little bitches you have to constantly keep up with.

Quite often a design will come with a few different rig choices, so you can scale up to better performance. Look up the latest offering from Dudley Dix Design, which I think it's the Paper Jet. It has three rigs and you can build up to high speed as you gain skill, just by installing different sails or masts. This is a boat small enough to slide sideways into a tight garage and light enough to man handle.

Assemble a list of prospects and get back to us. Many will be obviously hot rods, but others may be "closet rockets" with bigger rigs.

 

Richard,

Test drive: I wasn't asking about stability. In building hovercraft parts, you sometimes use 1/8 plywood as a structural component in a propeller shaft mount for over 100 hp. Before it's done, it hardly stands up by itself. When you do get done, it holds up nicely, and for years. All I wanted to do was see if it had the shape I wanted, then take it back apart.

Case in point, there is an article on lofting in one of the plans sites, I think it was. The guys who don't loft put a couple ribs or forms in place and then put the piece in and take it out to shave it repeatedly. In thinking about the scaling project, I wondered if I could make the parts the exactly correct shape in the first try, and wanted to know about test fitting. Since the board bends during the stitching, I just wanted to know if it could work that way.

That said, you guys have sufficiently explained the scaling problem. I won't do that, but I would still like to know if by stitching without glue first you destroy the part, or how many times you could test fit it.

Strip planking or something similar is certainly in the cards. Wood core is a valid composite structure, and it would let me have the wood look too, which if it has no significant drawbacks I would definitely like.

First boat: It's my first boat, you guys know by now that I've built other projects. I wasn't being defensive about it, I was trying to give you guys an idea of my experience in tools and building.

420: So this is actually a high performance boat? In that case, what I would be after in a single hull design is something similar, in wood perhaps, which can be rigged to be slower and then work my way up to something faster than what Northwestern University's sailing center uses as their school boats.

Wood: If I am going to go with wood, I would prefer a non-plywood design if it's not too much more work and not any more weight.



Stan,
I've spent some time on the Glen-L site, the problem is knowing anything at all about what I'm looking at. I can't see performance as easily as you do, nor do I know a good design from a bad one.

My original reason for this thread was to get some book recommendations so I could buy them, read up in the next month or two and then not waste everyone's time by asking all these silly beginner questions on a forum.

My most desperately needed books:
- A book about different boat types and their characteristics, and general boat terminology.
- A book about construction techniques and best practices, tips, tricks, how-to's and such.
- A book about rigging and operation best practices, how to be a sailor.



Par,
I bought the cheap well-used hovercraft at first, and stuck with it for 8 years. I would rather start with something I can learn on and grow into as well.

That Paper Jet looks really interesting. The only thing is, I can't find anywhere it says how big a guy it can hold. Two teenagers, well I weigh that much, or more than that, or less than that depending on the teenagers.

I could build that as a first boat and be happy with it. That "wet deck" design is something I was going to ask about but never got around to it. I spent enough time bailing one day that I would want that on my boat.

 

Give PAR a PM, click his name, he will recommend some books. I have only one to mention, but I´m the Wood/Epoxy man anyway.

"Gougeon Brothers on boat construction"

If one is not able to build a boat after reading (and understanding) that book, he should either buy one, or slap his parents.

Strip planking is as easy (PAR and I persist in saying easier) than stitch and glue. But can produce much finer hulls and attract the eye much more.

Regards
Richard

 

With the exception of the Lord method and my bastardized version of it (Lord/PAR method), you'll be heavier then typical taped seam builds with strip planking. The advantage of strip planking is you can build complex round shapes easily and it's user friendly.

Taped seam (stitch and glue) usually is "adjusted" during the stitching process. The seams don't have to be very precise, in fact they generally aren't, with 1/2" gaps being easily filled.

The Paper Jet is a real screamer, though appears a fairly well behaved thing under the smaller rigs. Under the smallest rig it still would be a handful for a novice sailor.

You're correct in that a 420 type of boat would be a likely target to shoot for.

The "Nature of Boats . . ." by Dave Geer will provide a good insight into shapes, why thing work and a bunch of boat stuff you may not be especially interested in.

The Gougeon Brothers book is an epoxy bible to many, if electing to go this route.

Have you explored the library on this site?

The best thing you can do is get as many rides on sailboats as you can. Go down to the local sailing club and crew for who ever needs a hand (some one always does). You'll learn a lot about how things work and get the opinions of like minded folks. Of course they'll all be wrong (just kidding, but not as much as you think), but you'll have a good jumping off point, more sailing experience and some time in widely differing boats.

 

A new book, The Boatbuilders Notebook By Glen L Witt is excellent in describing types of boat building with pics. and gives you all the terminology used in boat building. It is a good resource book to have handy and will elevate your knowledge above niafite( young brave ) Best, Stan

 

THANK YOU THANK YOU THANK YOU!

I will check these books out and start reading, and hopefully my pesky questions will slow down for a while.

Keep in mind here that if I appear to be ignoring your advice or arguing with you, I probably don't know what you mean by something.

Case in point, the boats. I would rather be slightly overwhelmed at the beginning, but not dangerously so. A few times being roughed up a little, or time spent learning before I can make it go, is better than being able to sail successfully the first day and then being bored with it shortly after. However, I don't know a screamer from a slowpoke.

I will see what I can do to take that sailing course at Northwestern University. That will give me a summer of practice on school boats, it turns out they have Lazers, 420'ers and some catamarans.

That Paper Jet does not impress me as a beautiful boat, but it looks like a stupendous amount of fun on almost any water I might find in my area. I could sacrifice taking a passenger if it would actually carry me and still perform.

I have some titles to look up, and thank you again for all your help!

PS:
I have not investigated this site's library. Some similar sites post any book somebody wants to sell, and perhaps none are very good. Others use a hand-picked set of books recommended by experienced experts. I prefer to find the experts by talking, it's pretty easy to figure out who builds boats and who just talks about it. Then I like to ask what they recommend in my case.

I'm not adverse to research, buying books and reading them. I am also not adverse to reading web sites, but generally the web site is not as high quality as the book for some reason. I am also not adverse to taking expert advice from people who I think understand my situation.

Thanks again.

 

Ok, Par, I'm coming up with a blank here.

Tried to find either your Lord/PAR method or just the Lord method of strip planking somewhere I could figure out what it is, and came up blank on both.

Is this in a book, or any sort of post that covers it basically? I see it referenced all over in forums, but not so far in any descriptive way that I can see what it's about.

Considering the amount of reference to you, you must have your own business and web site somewhere. Do you mind sharing that, or is there some rule about that on this forum?

Thanks.

 

Ken
there is no such rule. But sooner or later you´ll notice, the nicer guys here are often the ones with the deeper insight, and the more humble too. And decent people do´nt beat their own drum, as you know.
I´m shure you´ll receive a PM or mail soon.
Regards
Richard

 

Can you use any type of strip planking on any design intended for strip planking?

Sorry, I don't have any books in my hands yet.

 

in principle

yes