A nice boat is one of the real pleasures of life, particularly when we have built it ourselves, with our own hands and using skills that we have developed over a range of projects. We put so much of ourselves into building a boat, in the form of time, effort, sweat, pain and occasionally some blood, that we should be proud of what we are doing. We do it out of love for what we are doing and what we are creating. We sometimes do it on a shoestring budget because we want to get as much boat as we can for the $$ that we can afford.
There are many places that we can cut costs and most of them involve us doing the work ourselves rather than paying a specialist worker to do it for us. That is a valid and satisfying way to reduce the cost of the project.
Another way is to reduce the costs of the hardware and other equipment. This can be by doing without a non-critical piece of equipment and accepting the possible reduction in efficiency. You might also find some reasonable used hardware to suit your boat that has enough life left in it to be worthwhile buying. Or you may choose to buy some cheaper hardware. It may be cheap because it is inferior and might give problems in use. Alternatively, it may be cheap because the products that you are buying are black market items, possibly stolen from the factory or from someone in the legal supply chain. You have no way to know the origin of this equipment if bought from a dubious source. If you can't establish for certain that it is legal product don't do it. You place your boat at risk of confiscation by the police and you may go to jail if you or your boat are found to have stolen goods, a risk not worth taking. Don't buy from dubious sources.
If you are a boat designer then you will, of course, use your own plans. If not, you will have to source plans for a boat that suits your needs. When researching what plans are available, bear in mind that the price that you will pay for the plans is very small when compared with the total cost of your new boat, probably less than 2% of the boat cost. This is not the right place to try to reduce the overall cost of your new boat project. It is unwise to build an expensive building on a cheap foundation.
To get to the real purpose of this post, you will occasionally see boat plans advertised by third parties who claim that they are unused and legal plans. They will sell to you at a fraction of the cost of buying those plans direct from the designer. Be wary of this offer, it might come back to bite you.
I currently have a situation that I am trying to resolve. I became aware of someone starting to build a boat to one of my designs far away from me. His name was unfamiliar to me and does not appear in my customer database. I contacted him to enquire about the plans he is using. He was convinced that he had legal unused plans because the person from whom he bought them told him so. That person was also not in our database but told us who had sold them to him, from another country thousands of miles away. That third person was the original buyer of the plans but by searching emails from years back it became clear that he had all of the structural components cut to build his boat from those plans soon after he bought them.
Boat plans are generally sold with a licence for the construction of only one boat; it is illegal to build more than one unless authorised by the designer. Before buying plans from anyone other than the designer or his agents you should contact the designer to ask if the plans can be sold to you, simply to protect yourself from possible future problems. If it can be confirmed that no boat was started to those plans then you will probably be able to buy them. If it can't be confirmed then don't take the chance.
The small saving that you might have from buying plans from an unauthorised source is really not worth the potential hassles attached to them. Not least of these hassles is the possibility that your local authorities will confiscate your boat. On a few occasions I have been requested to supply a letter confirming that a builder had the legal rights to build the boat. This information is required by some national authorities, who are increasingly clamping down on copyright infringements. Boat plans are intellectual property so anyone using them illegally is stealing from the designer and opening themselves up to prosecution.
The other factor that comes into this is that you should endeavour to have a good relationship with the designer of the boat that you are building. No-matter how good the plans are, there may be times when you want to ask a question to clarify an issue. If you have bought unauthorised plans then you cannot expect to receive any support from the designer, you will be on your own. All this trouble, just to save yourself maybe 1% of the cost of your complete boat.