Re: Zodiac pontoon end difference??
The old cone design was dictated by the original manufacturing process more than anything having to do with performance. When Zodiac switched to the plastic-coated fabric and thermobonding in the late 70s, the design stayed the same because....that's how they'd always done it.
With the change to heavier 4-stroke engines, however, it's become more important to add buoyancy aft of the transom, which is why you see that the new designs go to the blunt ends and that the tubes now taper to a larger diameter toward the back. The side benefit is that the new design also opened up a few more inches of interior length, as the transom can be positioned further back than it was on the older designs (the ones still being made for West Marine).
