Buoyancy.
The scariest fallacy MacGregor marketing has stated here is this: 'Most competing boats do not offer this essential safety protection, and their heavy keels can pull them straight to the bottom. Don't get a boat without solid flotation!' The fact is that nearly ALL competing boats use positive ballast-- meaning that their displacement stays the same (is not removable). They do not NEED foam floatation because they are inherently stable. They heel less, and when they do heel the righting moment of the keel greatly surpasses the ability of a bottom full of water to re-right the boat. Even a small swing-keel boat (like an older Venture) with the board locked down is better than a boat relying primarily on water ballast (like the 26X). All things being equal, the boat with a lead or iron keel will be MUCH more stable (able to self-right) than one with water ballast. And it's not the weight figure in pounds so much as it is where the weight is and how much space it takes up. The concentration of the weight is crucial. I just stated this elsewhere in this forum: the greater the volume for a given pound of ballast, the more unstable the boat. This is why high-performance, ultra-low-displacement race boats have long deep keels with bulbs at the bottom, concentrating their ballast weight there, thus making a long arm and moment-- and then they often specify SPENT URANIUM because it's even denser than lead!! In this way they get a greater percentage of their total weight into a smaller space. Try this. Take 25 one-ounce sinkers. Put them all over the bottom of a small plastic toy boat. Now take one 25-oz sinker and glue it on the bottom of another boat (like a keel). Which boat wiggles less in the bathtub? Which one tips over faster by your finger? The one with 25 sinkers is a water-ballasted boat, in which all the weight is spread over the whole bottom. The one with one weight is a keel boat. THAT is why there are such things as fixed keels in the first place. In answer to your question, the Mac 26X full of water does not sink only because of the foam added in. Most normal keelboats will continue to float nearly full of water as well (we have hundreds of racing mishaps to bear this out-- it's usually safer to stay with the half-sunken boat than to abandon ship). In a certain sense a partially-filled hull DOES add to stability at sea-- the boat moves less and stays put. There IS however a 'window of buoyancy'. Exceed it, and the boat will sink. The 26X's positive flotation is the ONLY reason why it does not sink (without it, it would). This feature does NOT, however, suggest that it is more stable than normal keelboats. My point is that actually, it is not-- otherwise MacGregor would not have included the foam as insurance for you (and them). JC 2
