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GURGLETROUSERS
Joined: 30 Dec 2009
Posts: 2643
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 Posted: Tue Aug 18, 2015 11:08 am Post subject: |
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Yes, my Mahalo tandem board with lightweight camping gear strapped up front, goes very well upwind whether railing or not. But it does have a huge daggerboard, a somewhat elongated front end (almost need a telescope to see it in misty conditions), and something like 293 litres of volume. I find it very pleasant.
But if you really want amazing, but short lived, angles upwind on an ordinary long board, try snapping off the fin as I once did, and sailing back in one foot either side of the fully extended daggerboard. Instant changes of pace and silly angles of direction guaranteed. Very invigorating - after you've climbed back on from however far away it has hurled you, before you manage to figure out how to cope! |
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whitevan01
Joined: 29 Jun 2007
Posts: 607
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| Posted: Tue Aug 18, 2015 11:58 am Post subject: |
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[quote="coachg"
The red sails are 9.0, the orange 9.8 and the yellow 7.4 based on the sailor's weight. They appear to be riding the boards flat but I can promise you they are applying pressure through their back foot toes to drive upwind off the centerboard. The guy out front in the picture is Andy Brandt who cut his teeth racing longboards in light wind. I'll tell him that you think you are faster upwind with your Atom 110, 7.5 Retro and that you feel his boom is too low. That ought to bring on a great laugh.
Coachg[/quote]
to amplify what you are saying, if one looks closely, one can see that Andy's board is not flat. also, it appears that he is in the process of bearing off to go around the mark that is in front of him. the people behind him are sailing a higher course than he is. |
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whitevan01
Joined: 29 Jun 2007
Posts: 607
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| Posted: Tue Aug 18, 2015 12:04 pm Post subject: |
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| konajoe wrote: |
| whitevan01 wrote: | | Heeling the board to leeward will cause the board to turn towards the wind and increases the effective waterline length, which causes the distance between the bow and stern waves to increase, thereby increasing speed through the water. |
Uh-oh. Here we go with mis-applying that waterline formula again. A board with it's centerboard down being sailed on it's leeward rail is capable of going WAAAAY faster than the answer that formula gives for maximum speed. Again, that keel boat max speed formula just doesn't apply to us.
But, when you rail a board to leeward, you make a leaner entry through the water. You effectively make it a narrower board, which cuts through the water better. The leeward rail down doesn't make the board turn upwind. When one rides with the centerboard down and leeward rail down, it rides perfectly straight. You will be able to point better with the rail down.
Now, if you sink the leeward rail back by the tail, that's a different story. |
so, my college professors were wrong? I did NOT reference the hull speed formula, and in a previous post I was one of the first to state that it did not apply to planing hulls like windsurfers. However, when a windsurf board is NOT planing, speed IS dictated by length.
try sailing equal displacement boards, say an Exocet Pacer 300 Pro hybrid board vs a Fanatic Megacat against each other with equal sail sizes in same wind - once again this is non-planing. the hybrid is much slower primarily because it is shorter, and takes longer to get up to speed because it has more resistance and has more mass, so it requires a bigger sail (more force).
heeling the board/boat reduces resistance which reduces the amount of force necessary to overcome drag thereby increasing terminal velocity (when forward force equals drag force).
so, basically, we agree konajoe.
I'm OUT!!!
Last edited by whitevan01 on Tue Aug 18, 2015 12:26 pm; edited 1 time in total |
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Sailboarder
Joined: 10 Apr 2011
Posts: 656
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| Posted: Tue Aug 18, 2015 12:05 pm Post subject: |
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| adywind wrote: |
And I can tell you right away that judging by the wake I'm going faster on my 110L AtomIQ and 7.5 Retro then those guys on their huge Konas and 8.5s??-they are spilling away too much wind and their daggers create too much drag IMO.
And why is everybody having their booms so ridiculously low are they going to ride waves in 40 kts after going around the corner ?! Too much old school stuff I guess. |
Look at your sail and the water state, there is way more wind in your picture... |
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Sailboarder
Joined: 10 Apr 2011
Posts: 656
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| Posted: Tue Aug 18, 2015 12:09 pm Post subject: |
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| whitevan01 wrote: |
heeling the board/boat reduces resistance which reduces the amount of force necessary to overcome drag thereby increasing terminal velocity (when forward force equals drag force).
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The other reason to heel the board is to reduce the useless force from the windward side of the nose that try to turn the board downwind. When heeling slightly to leeward, even in low wind, the nose and the daggerboard work together. |
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techno900
Joined: 28 Mar 2001
Posts: 4161
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| Posted: Wed Aug 19, 2015 7:22 am Post subject: |
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The main reason to sink the leeward rail is to use the hull as a 12' long 4" high dagger board. This really helps with pointing. When a board sits flat on the water, there will be less lateral resistance than when it is heeled over, using the side of the board to resist sliding sideways. The "boxier" the rail/side of the board, the better.
Displacement hulls do really well upwind, because they have a much greater lateral resistance than a planing hull. There is simply a lot more board/boat under water. However, as I said, a planing hull like a Equipe II XR that has boxy rails that resist lateral sliding when heeled over will also point extremely well.
In light winds, under 5 knots, it takes a lot of technique to rail the board. In stronger winds, they will rail on their own. |
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konajoe
Joined: 28 Feb 2010
Posts: 517
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| Posted: Wed Aug 19, 2015 8:04 am Post subject: |
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| whitevan01 wrote: |
try sailing equal displacement boards, say an Exocet Pacer 300 Pro hybrid board vs a Fanatic Megacat against each other with equal sail sizes in same wind - once again this is non-planing. the hybrid is much slower primarily because it is shorter |
The Pacer is harder to pull through the water than the Megacat because it is wider.
Again, a 30 ft keel boat has a constant waterline, regardless of speed. The waterline of my longboards changes continuously with increased speed. |
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boardsurfr
Joined: 23 Aug 2001
Posts: 1266
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| Posted: Wed Aug 19, 2015 8:28 am Post subject: |
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| whitevan01 wrote: | | However, when a windsurf board is NOT planing, speed IS dictated by length. |
Mostly agreed. Although form factors play a roll on how much sail you need to get to the speed, and some hulls may be a bit faster than others at the same length. But mostly, it's length.
| whitevan01 wrote: | try sailing equal displacement boards, say an Exocet Pacer 300 Pro hybrid board vs a Fanatic Megacat against each other with equal sail sizes in same wind - once again this is non-planing. the hybrid is much slower primarily because it is shorter, and takes longer to get up to speed because it has more resistance and has more mass, so it requires a bigger sail (more force).
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We did a few practice races last year, using a Starboard Phantom 320, and Ultra Cat, an Equipe, and a Kona Mahalo (which is a couple of inches longer than the Cat and Equipe), with 7.5 m sails. We switched boards a few times.
Interestingly, the Phantom was able to keep up quite well even in light winds - if it was railed up. It's huge dagger board makes it rail up quickly, and it had the boxiest rails of all boards. Andy Brandt has called railing up "planing on the daggerboard and the rails", and there is definitely something to this. With the daggerboard, the transition to partially planing was quite smooth, despite the shorter length. It also was quite seamless - not an all-or-nothing transition as on a shortboard.
The Kona Mahalo, despite the longest waterline, was not the fastest board. It did ok in flat water, but was quite a bit slower in chop. Several issues contributed - the smaller daggerboard, the round rails, and the fat nose that slowed the board down noticeably when slamming into chop.
Going around the course, the biggest difference was not the board, though - it was rider skills, longboard experience, and (in almost-planing conditions) body weight. The Phantom 320 fell behind a lot if the rider did not rail it; I've seen the same with other longboards. When the wind picked up to 12-15, the lighter riders left the heavier ones in the dust. No surprise hear, that was one of the problems with longboard racing. One of the great things about Kona One racing is that the handicap system fixes this problem quite nicely. Heavier sailors can use larger sails, but they also benefit from a slightly longer waterline, so racing between different weight classes is very fair. Although due to factors similar to the ones listed above for the Mahalo, the Kona One is not as fast as older racing longboards. |
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konajoe
Joined: 28 Feb 2010
Posts: 517
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| Posted: Wed Aug 19, 2015 8:41 am Post subject: |
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| boardsurfr wrote: | | One of the great things about Kona One racing is that the handicap system fixes this problem quite nicely. Heavier sailors can use larger sails, but they also benefit from a slightly longer waterline, so racing between different weight classes is very fair. Although due to factors similar to the ones listed above for the Mahalo, the Kona One is not as fast as older racing longboards. |
Another bad waterline theory.
In Kona racing, ANY woman, regardless of weight, can use the 7.4. Males have to weigh at least 65 kg. History from major Kona events show that light women have an advantage over the men on 7.4s in light wind, even though the men have a longer waterline. |
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GURGLETROUSERS
Joined: 30 Dec 2009
Posts: 2643
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| Posted: Wed Aug 19, 2015 9:35 am Post subject: |
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Agreed, the Kona and Mahalo are not as fast as the old racing longboards, in LIGHT winds. Even my Bamba with its thick boxy rails and quite efficient daggerboard and fin, is faster, and points a little higher.
But, in strong planing winds the Kona can really light up. Patrice (Exocet) has claimed 30 knots on both the Kona, and the MAHALO! (Bet the front end pilot was petrified!)
What the Kona really has going for it, is the comfort and balance (step tail-reduced water line length) when planing hard in the straps. That is well worth the small sacrifice to the older boards in sub planing glide and upwind pointing ability in light winds.
It will, of course, easily beat any short non daggerboard hull upwind, downwind, or wherever, in light wind sub planing conditions. It simply 'gets there' reliably, and with certainty.
Exactly what's needed for extended cruising. |
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