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Farr 11.6 (Farr 38)
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Water Sky Boat Watercraft Vehicle


That is Synergy on the right. At the risk of asking that one dreaded question, "Do you think that this makes my backside look big?"
 
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Discussion Starter · #7 ·
OMG I love this thread!
I like weird shaped boats, what does that mean? Sorry is there a therapist in the room? To me below has the coolest boat profile (from behind anyway) yeah I know its a racing rule that defined it, but still.

Not my boat - so if it is yours, yeah I have boat envy. (It's a Catalina 38 by the way).
Water Sky Boat Watercraft Vehicle
 

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Farr 11.6 (Farr 38)
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OMG I love this thread!
I like weird shaped boats, what does that mean? Sorry is there a therapist in the room? To me below has the coolest boat profile (from behind anyway) yeah I know its a racing rule that defined it, but still. . (It's a Catalina 38 by the way).
I never liked that look, but I have a friend who was in love with the looks of the Catalina 38 . He asked me what I had against the Catalina 38. I ended up plotting a stability curve for the Catalina 38 to explain some of my concerns. It was really interesting.

If you talk with most folks with older designs that tend to be tender and heel easily initially, they will tell you that it feels like their boats heel quickly until some angle of heel (maybe 20 degrees) and then seem to stiffen up. That is not just a feeling. There are a number of reasons that is true, but the single biggest reason is the shape of the stability curve around that angle of heel, with stability increasing very slowly until that point, but then stability increases sharply as the topsides enter the water and the boat starts developing form stability from their topsides. That bulge lasts until the edge of the deck hits the water, roughly a range 20-25 degrees.

When you plot the stability curve for these IOR-1 boats with the extreme tumblehome, they never do build form stability. So you see a curve that very slowly builds stability with heel angle, until you get to somewhere around 30-35 degrees of heel, but then it starts to quickly drop as the tumblehome hits the water and for maybe 10-15 degrees of heel it drops pretty steeply. At that point, it starts dropping much more slowly and maybe even increasing slightly as the hull is sitting on its topsides, deck and cabin sides, with the keel approaching horizontal. and then starts to drop again slowly as the boat starts to invert.

It was the strangest stability curve that I have ever seen. But that (and the rig proportions) are the main reason that I have never liked those boats.

Jeff
 
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Discussion Starter · #12 ·
Jeff: FYI in my opinion it looks as you describe, that it'd heel quick stiffen for a short bit then release and heel quick again. I didn't say that my fondness of IOR designs was a good thing. It is an irrational affliction actually. Would love to see the curve if you have it plotted somewhere.

I'm a weird sailor, I love the classic heavy full keel designs, teak decks, and canoe sterns, but I like to sail something completely different. Ironically the prettiest sailboats to me are one's I'd probably hate to sail. I blame my father for my different tastes in sailboats. I fear calling out any one particular boat by name that I love to look at but would not ever want to sail in case I might offend. I think I'd love to sail the Cat38 though, and I think its oddly very pretty to me.
 

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Farr 11.6 (Farr 38)
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I am a big fan of the way a lot of boats look that I would not enjoy owning. I love looking at Concordia Yawls, H-28's, 12 meters, early Alden schooners, Friendship sloops, Luders 16's and 24's, and Beetle cats to name a few. I am always grateful when I see one sail by and thank the owner for making my day nicer.

This was a slide from a lecture that I gave some years ago that included the plot of the Catalina 38 stability curve and of an IMS boat of from the early 21st century. The IMS boat was substantially lighter yet developed quite a bit more stability. I will note that pretty much all boats loose stability when the deck edge hits the water. In the case of the IMS boat that hollow hits around 60 degrees, then bounces up when the cabin side hits the water. The Cat 38 cabin side hits the water at a lower angle of heel. (The CB on the graphics are for the entire boat, as is the CG. They do not account for shifting fluids in the tanks).
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Water Sky Boat Watercraft Vehicle

Here's the one we sold last summer. We had the name written in big letters so our competitors would still be able to see who beat them from where they were.
Cloud Sky Water Boat Watercraft

This is the "new" boat about two minutes after the start. A competitor graciously moved to leeward and behind so he could take this shot. The letters are smaller. We got new sails for Christmas. We're still learning how to make her go.
Water Sky Boat Watercraft Mast

This is the dinghy - Étoile. She goes faster when we're not dragging the spinnaker sheets.
 
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