Micro with chine runners?
Just wondering if anyone has thought of putting chine runners on a Micro similar to Matt Layden's Paradox?
Would they reduce leeway at all or just introduce a lot of drag with no benefit?
Just a thought. Brent
Well, Harry the claim is they work, but...
Speed might come into it, and slender hulls make for higher speeds. However, the slender hulls are immersed sufficient to resist leeway themselves. I'm far from persuaded on a number of grounds. Bernd has many capable and attractive catamaran designs, and he specifies those small horizontal triangular panels on some designs be fitted to only the inner chine of each asymmetric hull, the sloping side. The outer side of the asymmetric hulls are near vertical - like a knife cutting through the water, no? The small "anti-vortex" appendages are supposed to reduce drag along the long inner hull side ... reduced drag for less leeway... ok then, so what's happening on the other windward hull windward side?
One attempt at an explanation for the claimed efficacy that gets around is to point at the winglets seen fitted normal in orientation to airplane wings at the tips. additionally, the wing chord is usually significantly reduced at the tip. The comparison falls short (no pun intended) on the relative geometries. Winglets are like endplates on the foils/keel of a boat, acting to reduce votices at the tip and downwash curving over the wing or foil. The winglets/panels are noticeably not appended to a wingless fuselage of an airplane - as TFJ wryly pointed out. Panels resembling "vortex anti-generators" in size and shape are however seen mid-body on missiles... at that power to weight and speed they must have been found to be satisfactory - but then how does a missile come in for a soft landing?
Pete Hill fitted the specified panels to his boat build ORYX, but shortly after crossing he removed them and fitted a low aspect keel to each hull (documented early in the blog below). Pete and Carly Hill have a little Q&A at the end of Carly's latest blog article touching on the panel issue:
"J.H. What do you like about ORYX, what would you do different?Pete Oryx is a very comfortable cruising home and she attracts favourable comments where ever she goes. I think Oryx would be a better boat if the hulls where fatter. The present waterline beam to length ratio is a little over 12:1. This is probably needed with the anti vortex panels, but they did not work very well on Oryx. Mr. Kohler talks of his average speed on his 'Pelican' as 9.6 knots! Maybe the anti vortex panels work at those sorts of speed, but Oryx's average is somewhere around 5 knots..."