Or works that were specifically put in public domain specifically to be free to use.
There are works like this, you can find many of them when looking into education programs. So if you search for boat building teaching material you are likely to come across open deigns.
Thank you
This is not copyright infrigement. It is better known as āfair useā.
I found this content to assist explain the Copyright Law of the United States of America other nation states have their own laws and should be followed in respective jurisdictions.
Copyright law and Related Laws Contained in Title 17 of the United States Code
Section 108
Ā§ 108. Limitations on exclusive rights: Reproduction by libraries and archives39
(a) Except as otherwise provided in this title and notwithstanding the provisions of section 106, it is not an infringement of copyright for a library or archives, or any of its employees acting within the scope of their employment, to reproduce no more than one copy or phonorecord of a work, except as provided in subsections (b) and Ā©, or to distribute such copy or phonorecord, under the conditions specified by this section, if-
(1) the reproduction or distribution is made without any purpose of direct or indirect commercial advantage;
(2) the collections of the library or archives are (i) open to the public, or (ii) available not only to researchers affiliated with the library or archives or with the institution of which it is a part, but also to other persons doing research in a specialized field; and
(3) the reproduction or distribution of the work includes a notice of copyright that appears on the copy or phonorecord that is reproduced under the provisions of this section, or includes a legend stating that the work may be protected by copy-right if no such notice can be found on the copy or phonorecord that is reproduced under the provisions of this section."
Archive.org is non-profit, and makes note of your original copyright (as published on your site)
This is akin to you having published a magazine, and the Library of Congress keeping a copy.
Additional material from the site archive.org:
"About the Archive
The Internet Archive is a 501Ā©(3) public nonprofit that was founded to build an āInternet library,ā with the purpose of offering permanent access for researchers, historians, and scholars to historical collections that exist in digital formatā¦
ā¦Why the Archive Is Building an āInternet Libraryā
Libraries exist to preserve societyās cultural artifacts and to provide access to them. If libraries are to continue to foster education and scholarship in this era of digital technology, itās essential for them to extend those functions into the digital worldā¦
The Internet Archive is working to prevent the Internet ā a new medium with major historical significance ā and other āborn-digitalā materials from disappearing into the past. Collaborating with institutions including the Library of Congress and the Smithsonian, we are working to permanently preserve a record of public material.
Open and free access to literature and other writings has long been considered essential to education and to the maintenance of an open society. Public and philanthropic enterprises have supported it through the ages.
The Internet Archive is opening its collections to researchers, historians, and scholars to ensure that they have free and permanent access to public materials. The Archive has no vested interest in the discoveries of the users of its collections, nor is it a grant-making organization.
In addition:
"Are you violating copyright laws?
No. Like your local libraryās collections, our collections consist of publicly available documents. Furthermore, our Web collection includes only pages that were available at no cost and without passwords or special privileges. And if they wish, the authors of Internet documents can remove their documents from the collection."
I declare āFair useā
ZzzzzzZzzzzzz
Legal arguments aside, and I didnāt mean to kick the hornetās nest (sorry @Bee). My biggest consideration is if the boats were designed for plywood and fiberglass. A classic boat with steam-bent ribs, frames, etc. would not be able to take advantage of a Maslow, which is what I thought was the whole point of this discussion. Luckily, there are a ton of boat designs available since they started using plywood in the 50ās.
I actually also got the digital plans for a kidās Optimist pram off Instructables a while ago. It also includes the design for the mold into which you bend the plywood structure so that it maintains its shape until the epoxy cures. This is a much better way to build an Opti because you can reuse the mold to build another Opti. The old school way was to build this big strongback, which you bent the plywood around, then you cut your boat free from the strongback once you had the bottom glassed, making the strongback just a pile of firewood. If you wanted another Opti, youād have to build another strongback. Luckily, I only have one kidā¦
If youāre willing to do the work translating, just about any decent boat design can be digitized. If the plans have enough info to lay out parts on plywood manually, then you can draw it up in CAD and youāre off to the races. So any of those older Popular Mechanics plans would be very doable.
A couple of boats I would stay away from are ones like Stevensonās Weekender and Vacationer, where the emphasis is on ease of build vs. an actually good sailboat. Thatās just my opinion after researching them on the forums. But I might be tempted to build a Mini-Cup due to its simplicity. BTW, it was featured in Popular Science. A small skiff like this is very comparable to a Laser, which I used to own or a Sunfish (especially with the lateen rig) or Snark/Super Snark.
Fair Use is not using someoneās plans without their approval, even for
personal use (if they wanted to sell the plans, you using them for free has
deprived them from a sale)
The Internet Archive section you are listing is misleading.
The majority of you local libraryās collection is not āpublicly available
documentsā, they are documents that have been purchased by the library.
I agree that the Internet Archive is Fair Use because they are only collecting
things that have been made available for anyone to read (and duplicate, at least
to the extent of being able to view them 
)
Thatās very different from the statement that āif itās in the library, then itās
public domainā
(somewhat) sorry for being a stickler here, but there is a lot of misinformation
out there over copyright, both from copyright holders and also from Makers or
āinformation wants to be freeā people.
Fair Use has specific limitations, but the way to think about it is that itās
probably Fair Use if you are only using a snippet out of something, and itās
seldom Fair Use if you use the entire thing. Itās designed for being able to
review documents or quote small snippets.
Well, no one should use me for legal advise. But look how much fun, they had back then.
Beside the legal issues, I guess that bonding and fastening technology has greatly improved, along with tools, etcā¦
Those lightweight catamarans can be really fast, which is good when youāre trying to outrun the copyright police just outside the frame of that imageā¦ 
I looked up Hobby Kat plans and found this thread forum, where the Quattro 16 (link in post #13 above) is suggested as a more current version.
Cats have pros and cons. Theyāre not displacement hulls, so you donāt have to build as much boat, but you do have to build two of them. The two hulls can be symmetrical (easier to build) or asymmetrical (better performance). They can also be a little tricky to tack, depending on their undercarriage (skeg vs. daggerboards, etc.) and whether they have a jib.
They are easy to transport, especially if you donāt mind assembling them on the beach, they can handle shallow water and theyāre much more difficult to capsize (but much more difficult to right). Thereās also much more surface area for crew as long as you donāt exceed the designed payload. It takes a bit of practice to hop to the other hull when tacking, but itās a lot of fun.
Interestingly enough, Iām taking a catamaran instructor course next week (for large, cruising cats).
The hobby kat is what I was looking at a few years back I think 4 years ago. You could pick on up used for a few hundred or if you were patient and the time you could find people giving them away. I had not looked at sailing in a while until I got here.
Thank you
Related but not woodworking. Iām working on an advanced āhang printerā itās a 3D printer that is āframelessā and can be configured to print large parts. One of the parts I thought of when I was trying to figure how to make something to take advantage of the fact Iād like to be able to make 30ft ( 9 meters + ) tall prints is custom Carbon Fiber Masts, although I now wonder about making a compost blend of Carbon Fiber and ASA. ASA is a UV stable printing plastic. Iām working on getting it in a company with a tall building as an entertainment and educational platform. If that project moves forward I would be able take on custom requests.
Thank you
This is the boat I want to build: http://rapidwhale.com/mini-boat.php
I think it looks like a ton of fun and would be easy to store/transport.
Iād like a smallish boat, but cruising the harbor in San Pedro you can end up sharing with a very large cruise ship. I want to be seen.
Thank you
This is beautiful -
Thank you
This is a nice build log for the Hobby Kat that was featured in the 1973 magazine Hobby Kat building he did make modifications going from 14 to 16 ft, etc. But at the end of the build he also notes several things that he would change. Changes to the rudder seem fixable, but placing holes in the bottom of the ribs to allow bilge water to drain from the aft, maybe not so easy after itās all been glassed in.
Yes, limber holes are very important to let the water out. My first boat was destroyed by water intrusion that couldnāt escape.
Interesting build blog. Thanks for sharing that.
@Bee thatās a pretty boat, but I didnāt really see much that could be done on a Maslow. Maybe some molds for laminating/bending stuff or the stems could be cut.
@MidnightMaker agreed - on not much Maslow can do on that one. I do a lot of research and sometimes it goes sideways. In fact the thread went to ride on human size quad copters. However that video hit a cord. I could smell the resin. Iām always trying to spark ideas.
Thank you
Regarding your visibility in San Pedro. Iām very familiar with that waterway and visibility is one reason why Iāve never gotten tanbark (red) sails for any of my boats. While I love the classic, pirate look, I donāt feel they have the same visibility as stark white dacron.
Iāve also been thinking about ways in which to convert a classic wooden boat build (with steam bent ribs/frames, etc.) into a more modern build. There are tons of classic boats that are beautiful that might be converted into CNC/stitch & glue and take advantage of modern plywood construction methods. This would entail having the plans digitized then using the stations as a template for drawing bulkheads that create the same shape.
One could also create laminated stems by bending them around forms that are cut, except you also have to account for some amount of springback. It would be an interesting exercise if you started with a boat design that incorporated a keel, deadwood, keelson, etc. and tried to figure out a way to make it CNC friendly without ruining the classic looks. Iām not ready to tackle this yet, but itās an interesting concept.
BTW, another boat design that is CNC friendly is John Welsfordās SCAMP (Small Craft Advisory Magazine Project). While a bit more of an ambitious build (around $15K), you end up with a very capable and seaworthy expedition/camping boat. I have followed several build blogs and seen numerous of these in person in Port Townsend. If you donāt mind its unusual pug-nosed look (more buoyancy in the bow), thereās a lot of boat packed into 12ā. It sports water ballast tanks for extra stability and there was a redesign to add a foot well for more ergonomics.
I have toyed around with the idea of building one, but for the price, you can buy a decent used fiberglass sailboat in the 20ā-30ā range. I guess it just depends on the journey you want to embark on.
I remember seeing them on Canada AM years ago when they did the first major expedition in these boats. A rowing flat water touring boat has since been intriguing to me.
Looks like you can get DXF files for the Expedition Rowboat directly from them. Thatās pretty cool! For long, thin boat, I think accuracy would be even more important than a more bulky dinghy. From Maslow usersā comments, it looks like theyāre getting acceptable accuracy, even on the edges of the plywood. At 18ā, theyāve probably designed a puzzle joint to join the three parts that make the planks/panels. That would be a very cool project, even though Iām not personally into kayaks, it would certainly showcase the power of digital fabrication.
I can see this as a growing movement once a few boats have been successfully built and go viral on social media. Imagine a quick video of watching the Maslow carve a part (i.e. puzzle joint) and then it cuts to splashing the boat for the first time. 
So inspired by this I have added a page in Community Garden for boat building
https://github.com/MaslowCNC/CommunityGarden/wiki/Boat-Building
Please add and edit as appropriate
Thank you