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| Is the Hobie 16 a "planing hull"? http://www.hobie.com/au/en/forums/viewtopic.php?f=14&t=71553 |
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| Author: | dorienc [ Sun Jul 14, 2024 11:44 am ] |
| Post subject: | Is the Hobie 16 a "planing hull"? |
OK, so on a FB forum, a member described the Hobie 16 as having a planing hull. He said that at its intended angle of heel, it would plane and that's why H 16s can do 30 MPH. I understand the intent of the asymmetrical hull is to alleviate the need for dagger boards, that the curve on the inside uses the Bernoulli Effect like an airplane wing (or a sail) to "lift" the hull towards the wind, enabling it to point somewhat higher. Would this "lift" be considered planing? Am I correct in my interpretation of the asymmetric design? Would any catamaran hull be considered "planing"? I've owned H17s and now a Getaway, both of which have nearly plumb bows and a rounded bottom. I don't think they plane though. |
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| Author: | srm [ Sun Jul 14, 2024 12:11 pm ] |
| Post subject: | Re: Is the Hobie 16 a "planing hull"? |
The H16 is the farthest thing from a planing hull. Planing is when the bottom of the hull generates enough upward lift that the hull climbs over its bow wave and begins skimming on the surface. Extreme examples of sailboats with planing hulls would be an International 14, Aussie 18 skiff, or a windsurfer. There are some beach cats with flat bottoms that will quasi-plane, but a Hobie 16 is not one of them. A H16 hull is intended to sit down in the water so that the steep sidewall, particularly at the stern, can act like a skeg. Its a hull shape that will never plane. sm |
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| Author: | dorienc [ Sun Jul 14, 2024 1:46 pm ] |
| Post subject: | Re: Is the Hobie 16 a "planing hull"? |
Thanks, SRM, that's what I thought. But this guy had me thinking about it as "planing" riding on a nearly vertical surface working against the wind force. 'Course he also thinks 30 is within reach of a H16 (I think I've read that 26 is about it?), and that a Laser is faster than a Getaway. |
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| Author: | AntonLargiader [ Wed Aug 21, 2024 10:31 am ] |
| Post subject: | Re: Is the Hobie 16 a "planing hull"? |
A laser will plane; it might not truly be a planing design but it will get out of displacement mode. A Hobie 16 won't. It is a displacement design and as pointed out it relies on the displacement to function. I have, however, experienced conditions when sailing solo (lightweight) where it heels and then slides up/sideways a bit out of the water. Not planing, and not even beneficial, but it does it. |
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| Author: | TucsonMike [ Sun Jan 19, 2025 8:11 am ] |
| Post subject: | Re: Is the Hobie 16 a "planing hull"? |
Sorry for the thread resurrection. I’m confused, then. Do cats have different rules for max hull speed? Clearly 20 knots or so is more than the 16 foot theoretical hull speed. |
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| Author: | srm [ Wed Jan 22, 2025 10:28 am ] |
| Post subject: | Re: Is the Hobie 16 a "planing hull"? |
Correct - catamarans are not bound by the classic hull speed calculation (1.34 x LWL, if I recall) which effectively calculates max hull speed based on the max wavelength of the hull. I believe this is because the catmaran hull is so slender that it is essentially able to pierce through its own hull wave, whereas a monohul would need to climb over its hull wave (plane) in order to exceed its theoretical hull speed. sm |
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| Author: | yaw_string [ Wed Jan 22, 2025 12:48 pm ] |
| Post subject: | Re: Is the Hobie 16 a "planing hull"? |
it's sqrt(lwl), and yes, sharp bow and sterns of either cats or monohulls (well under 30 degrees, like rowing sculls) generate too low waves to matter: https://www.yachtingmonthly.com/sailing ... myth-82832 |
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