So I would like to open up a topic for debate. I have heard several opinions on the matter, but I think it best to open up the discussion to the collective reasoning of the 505 class.
As I see it, there are two 505 builders who have consistently been at the top of the fleet each year at the world championships. In 2009 we saw a decisive victory by Mike Martin sailing a Waterat in the trying conditions on San Francisco bay; but at this year's world's, which saw the full spectrum of sailing conditions, it was Rondar that took the top three positions.
From what Rondar proponents have told me.... the Rondar hull is a bit "fuller" at the measurement points, gets onto a plane more quickly and has a livelier feel to it, whereas the Waterat is closer to the minimum at the measurement points and sits a little lower in the water.
With Waterat on the otherhand..... Larry Tuttle is second to none when it comes to quality of construction, durability and longevity. It seems as though a well cared for Waterat will last almost indefinitely. Some also say they're faster.
And for the other builders.....Van Munster, Fremantle, etc. What's up with them? Why don't we see them at the top of the fleet? Why aren't the best sailors racing them?
So if you have a qualified opinion on the matter, please lend your thoughts on which boat builder is better........ and why!
I am definitely not the most qualified to answer this but I have done a lot of sailing in my waterat (8645) and Tyler Moore's 8629. I have also spent a good chunk of time in Lindsays and Rondars. From my perspective on the wire the Rondar seems to jump waves a little easier. The Lindsay seems to plow waves the most and the waterat seems to be somewhere in between. I think the 'livelier' feel has more to do with weight distribution than anything. The new(er) Rondars seem to me to be light in the ends and built with extra reinforcement in the middle. I am thinking, specifically, of the Holger Jess Rondars with their steel plates AND correctors within the cockpit. The waterat, on the other hand, has a consistent laminate throughout and is built to withstand pretty much anything that is thrown at it. As a result, and I think part of this is also due to the launcher tube being built the way it is, the boat tends to be more 'consistent' in the distribution of its weight. I find when I am flipping the Rondar I am sailing now (8987) it goes over quite easily. My waterat takes a little more leverage. Of course, my waterat was one of the lightest boats at the 2009 Worlds which didn't need to be brought up to weight...I think we were 129.1 kg...so it's not 'weight' but how it's distributed.
That was a long paragraph. I also took measurements of the WitchCraft, Lindsay and waterat when we were building 505s. It was interesting to note the symmetry of the various hulls and also where the volume was (is). I can send you that file if you're interested. It definitely highlights the difference not only in the shape athwartships but also the rocker.
I have come to the conclusion that anecdotal differences between the performance of a good Waterat vs a good Rondar are total crap (I am assuming similar values of stiffness, weight, and moment of inertia). I think the major issues at play here are how you sail the boat and to some extent what your overall combined crew weight is. In my mind, it's not even worth debating because differences in sail trim and how you move your weight in the boat ouitweigh very small differences in hull shape. Look at Pegasus for example. They paid for a top Nav Arch to study and produce a new optimized hullform. As far as i know, they did not produce a better result and have not been able to quantify any performance differences.
If you were to develop a hullform specifically for sub-planing conditions, perhaps you would do some things different, like go back to a more extreme rocker profile to reduce wetted surface. But, 505's need to be a balanced design and fast in all conditions. It doesn't take that much wind for a design in one corner of the performance spectrum to be quickly outmoded.