[quote=texastuma][quote=anopheles][quote=texastuma]
For the inverted bow Nader, I have it as a concept in my head; no real buoyancy calcs, just experience of what could to be improved. I did see a H21 with inverted bows added.. I haven't sailed it, but would be willing to. Before you start designing, I would recommend you sail a few of these suggestions to get some experience of what can be improved. And, I mean sail them hard... aim to hit speeds over 25 knots. I originally envisioned a tear-drop hull shape similar to the Nacra 5.8 or 6.0 with the bottom third of the hull the widest point. But, having a sharp bow helps in the high speeds. I would look at making the deck rounder forward of the front beam; it eliminates some weight cutting the edges off but it also would help in the cases it does go under at speed. I would look at flattening the exit at the stern waterline. In medium speeds, the stern may skid around a bit with waves, but I think it would hit second gear sooner.
This is all concept in my head as I rather use what I can find and get on the water.[/quote]
Just came across this thread. Have you decided?
The hull designs you are considering, Tornado vs modern (F18 style) have very different design philosophies. The tornado has a deep forefoot, and it gets its forward buoyancy from being tall. Deeper submergence, more boyancy. The modern inverted bows are designed to be practically out of the water. These boats are designed to get their buoyancy from a “belly” drooping down a bit, underneath the centre of the hull. The fronts of the hulls are wider than the Tornado, but that doesn’t matter, because they are barely in the water. When forward buoyancy is needed, that’s when submergence of the bow provides lift.
You might want to consider this if you want to just put an inverted bow on a Tornado, even if you extend it. Also, if you extend the tornado hull, do you do a lot of tacking? Because with a longer, deeper bow under water, it’s not going to turn well at all.
The deeper belly of the modern F-18 style cats gives it much more flotation in the centre of the boat, keeping bow and stern shallower, making turning much easier. It pivots around the centre.
A couple thoughts.
KEdited by anopheles on Jan 06, 2024 - 10:33 PM. [/quote]
Nothing more than a thought and conversation over a cocktail... To adapt a Tornado, you'd have to redo the entire section forward of the crossbeam. Drop the freeboard and reshape the decks.. If I had a Nader to chop, it could be done... I got the opportunity to sail an Infusion and was beyond impressed with the wave handling... I agree with your assessment of the bouyancy... Having a flat section aft of the front beam would be the ticket... just like the Cirrus 901.[/quote]
