Over the years I have written (some might say ranted) a lot against the evils of poor yacht design. And with justification, since there are few things sadder than a boat that doesn't sail or motor very well, no matter how much power (engine or sails) we throw at it.
After all, we do this for fun, so surely we all want the pleasure of knowing that our boat operates in an efficient way in the medium she was designed for. And even if we don't care, a good hull design is both more fun to sail or motor and safer—slow increases our exposure to bad weather, reduces manoeuvrability, and increases the load on the gear and crew.
But the sad fact is that many, perhaps most, boats out there have poor hull designs. I have already dealt with how that happens (see Further Reading), so this article is about what we can do to avoid ending up with one of those woofers. As so often happens, I was inspired by a comment from a member:
I am struggling to apply this information into selecting a hull that is appropriate out of the universe of boats available on the used market (within my budget). For a newbie, what advice would you provide to help identify a good hull from bad. I am unable to find prismatic coefficient for the boats I am considering. Is there anything else I can use as a proxy? Max hull speed is sometimes available. I want to make the right decision…but I don’t know how.
So let's start by answering his question: There's no single number, shortcut, or even group of numbers that will tell us whether or not the designer did their job properly or, as so often happens, was persuaded to do bad stuff by others (almost always in an effort to cram too much interior into a boat).
And to make things even more complicated, good design is a moving target depending on how each of us intend to use the boat.
Given that, there are only two ways to avoid buying a bad boat: