Buying a yacht
Bruce Roberts is a popular designer of off the shelf plans for amatuer builders. He has probably solds more stock plans than any individual designer. While he has done some reasonably good designs, I am not a big fan of his work. While I think that for the most part Roberts designs conservative simple boats, by any reasonable standard, they are very dated and many of his designs produce just plain bad boats. He has two popular design series, one based on Slocum''s Spray, and the other is a bit more modern. Most of his more modern designs seem to be based on 1960''s and 1970''s thinking, and the science of yacht design has greatly advanced since then in terms of understanding motion comfort and seaworthiness. To me Bruce Roberts designs generally do not seem to take advantage of these lessons. Roberts has refined some of his earlier designs producing some boats that I think are better designs than they were in thier original form. A good example of that is the boat he calls a 434 that someone built as a long range single-hander looks like a nice boat.
More to your specific questions, there are two Robert''s 36''s. The one is a part of Robert''s Spray series. His Spray series boats have less than no appeal to me personally. Having read detailed accounts of the original Spray and the sailing ability of some of the so- called copies of her, I have come to believe that Josh Slocum was the consummate seaman who made it around the world despite the short comings of Spray rather than because of Spray''s sterling virtues. He chose Spray because she was free not because she was well suited for offshore work. Spray began life as a a coastal oyster smack. Why anyone in this day and age would want to use her as a model for a whole line of boats is completely beyond me. But I emphasize this is only my opinion and Roberts has sold a bunch of these things so my opinion is not shared by everyone on this. Having sailed on as lightly longer version of his Spray series, I found the boat to be a miserable sailor and not a boat that I would consider very well suited either for coastal or offshore work.
The other Robert''s 36 was probably a late 1960''s or early 1970''s design. It is a prime example of what I was saying about yacht design and engineering really advancing over the past 40 years but Roberts designs being trapped in a period when yacht design really was not very good. Built to the drawings, these boats were mediocre sailors. But most amateur built versions exceeded design weight and were under ballasted as compared to the design ballast furtehr reducing sailing ability. With the extreme shallow draft of this design they would tend to be tender in relation to their comparatively large amount of drag. That is a combination that results in a dismal performer with real problems at the light and heavy end of the windspeed range.
By any objective standard these are rediculously heavy boats. I strongly believe that weight, in and of itself, has no inherent virtue and is by its very nature a very serious liability. In a design like this the extra weight does not contribute to seaworthiness, motion comfort, strength, or carrying capacity. It just adds to the stresses on the boat and crew.
Which brings us to the other amateur construction issues. Amateur built glass boats generally have mediocre to poor glass work. They are rarely laid up in a condensed period of time which means that there is often contamination and secondary bonds within the laminate, which greatly weaken the impact resistance and increases the propensity for fatique. Amateurs tended to use a lot of fillers, end up with resin rich laminates and use a lot of non-directional fabrics all of which further increases the tendancy toward reduced impact resistance and fatique and a greatly increased maintenance regime. Given the 1970''s build period this is also likely to be a boat that will be prone towards serious blistering problems.
Then there is the idea of building a boat that is little more than a hull and rig. I have been involved in and consulted on a number of these projects. Boats like the boat in question have a limited value even when they are carefully constructed and in perfect shape. The fears about amateur construction and the issues of poor sailing abiltity will always keep a boat like this at the very bottom of the fair market price range for boats of this size.
When you talk about rebuilding a boat from the condition that this boat is in, you are going to be buying a lot of materials and perhaps subcontracting some skilled labor. Like building a car from the spare parts bin, the total cost of materials needed to put a boat like this back together is so extensive that it can easly equal far more than the boat will ever be worth in the open market place and that does not include any payment towards your time and labor. In otherwords rebuilding a boat of a mediocre somewhat obsolete design, with a less than perfect heritage, or home construction, that has already been sunk once, in most cases, makes absolutely no monetary sense.
On the other hand, many people get a lot of joy from working on boats. For them the process of rebuilding a boat may equal or even exceed the joy of sailing a boat and if you are that kind of person then perhaps a project like this might make sense even if it did not make economic sense.
The reality from a time and money standpoint is you would be way better off finding a better designed and built production boat that has been properly maintained and updated. Boats like the one that you are considering in reality can easily have a negative fair market value.