i think you're playing with words there nebs,
yes cutouts reduce wetted surface area. and yes that makes you go faster.
I recently got an F2 SX-L with deep recesses and plates to adjust the depth. I was told by a few people, and also read on some forum, to only put in the plates when the conditions are really choppy - to help then keep the nose down. I don't know what to believe - I would have thought the shallower plates would help to get planing in lighter conditions, but I know sweet f@#k all.
i weigh 80kgs at the most and shed 5kgs by the end of the season due to no work and all play
can you post a pic of those cutouts decrepit
Here is my take .
Wide tailed boards generally trim flatter , nose down and can be "sticky" . Tail cuts alter the trim and allow the nose to lift freeing the board up . As discussed this can be acheived in other ways like a larger fin ,placing the straps further back , mast track further back , boom higher ect , so tail cuts are just one tool to acheive a looser and faster ride .
When designing a board it,s a balancing act around a whole list of parameters and tail cuts are just one way of acheiving the desired result . They are not a "wank", they work , but only when part of the initial design equation.
I was loaned a Tabou Rocket with out cutouts yesterday nice board and fast but I can't wait to get my F2 Stoke back on the water as it's far more comfortable and cut's through the water better.The owner of the Tabou was impressed with the f2's ride and could see why when he thought about the cutouts.
i allso had a 105 rocket, and replaced it with a carbon art 55.(because the c/arts smoke to windward) the board is fautless no cutouts sails sizes 5.0 to a 7.3 with eaze, thats the board im tooling up for, dropping the rockerline and adding a bit of tail lift and hopefully come up with about 80lts, the only thing i'm not sure on is these cutouts, but at the end of the day if there not working i can fill them in without adding hardly any extra weight
i was looking at the f2 web site and all there boards look great(i noticed they have a mini stringer), when ive finnished this board i'm going to make a freestyle board like the chille but wider and thinner, but ill have to have a look at one so i can see the tail sliders . or if someone has a closeup pic i'm sure it wont be a problem on this site everyone is so helpful
My 2 bobs - (what do you call twins with no arms or legs in a swimming pool)
Wetted area is a function of 1) All up weight, 2) board speed, 3) width (aspect ratio)
4) angle of attack (pitch). I think that's all.
So cutouts allow the use of wide tails that provide high aspect ratio planing surfaces which provide higher lift to area ratio hence - less wetted area. According to that theory they should be faster. I think they would be but for 3 things 1) windage, 2) The planing patch required at high speed is so small that pitch control becomes an issue for wide tails. 3) They require more fin.
The cutouts just allow the fin to be positioned appropriately vis a vis the planing surface. IMHO. FWIW. dont quote me. why did i open my ignorant mouth to bore you all with such vacuous drivel. kill me now. no dont bother. I'm not worth the exertion. Stewie I need an acronym for utter self abasement.
jeez mate,
get a grip,
p.s. you should have left your original response up rather than editing it into the garbled mess it is now.
I wonder about tail rocker. I have always thought it would create drag by sucking water upwards. However as the water has already been pushed down then it will be under a bit of pressure. I guess if the rocker is just right it can allow the water to accelerate upwards under this pressure without actually doing any sucking work. The result would be less lift on the tail with no extra drag due to sucking. However you end up with more wetted area than the minimum required to provide lift.
yeah and waveboards could be shaped like flying fish and speed boards like barracuda (oh wait, they are)
Having built my current speedboard without cutouts and then adding them at a latter date I can offer these points.
The cutout cured a bad rocker line (too much flat)
Reduced the wetted area but increased drag at lower speeds
Reduced its ability to point upwind
Increased its stability in chop or rough conditions
Allowed the board to "fly" much more off the fin
Would i do it again No ,complacates the design
Nebs said
While I was talking with slowy about my cutouts, I think he said that the carbon arts don't hace cutouts because they have tail rocker instead.
So I'd think if you increase the amount of tail rocker the carbon art has, and put in cutouts, you may end up overcooking it.
Too much angle of attack and slow the board down, but it will be nice and loose.
Select to expand quotedecrepit said...As I said mine is flat for 1100mm but with the cutouts I can sit it on the fin. wow those cutouts must be working overtime decrepit with that rocker, it must be a fully blown speed board its good to know they work
believe me theres no tail rocker in the c/art, the c/art is a great board and i love sailing it but i need an 80lt
if i got james dennise to make me another board designed by phil mcgain id have to grow about 8" change my shoe sizefrom 7 1/2 to about a 14 and stick on about 25kgs, now i dont know how tall, or phils weight or shoe sizs but i had to change the foot straps, "maybe they use boots over there" there is only one possition on them and i would have liked them futher back, the back ones 20mm and the front back 45mm theres allso heeps of volume on the tail with me being 5'7 and 75kgs naturally i need less volume and shoten the straps, but haveing said that the board will carry a 7.3 sail with a 32 fin so that could be the reasoning not bad for a 94lt board
sorry for the dribble but i will stick the tail rocker in and if i dont like it ill take it out "you know if you use a blender to mix your balloons they blow up much better and by useing the blender too mix you wont get any pinholes in your filler coat"
2mm of balloons weigh buggar all but i think 1100 strait plainning for me even with cutouts is a tad to much im looking at a high wind slalom
I certainly wasn't recommending 1100 straight, my speed board is a modified wave board, I ripped the old d'cell layer off, added more low density foam and re-d'celled it, to get rid of the old wave rocker.
I really wanted about 1m straight but it was very hard to measure what was going on, so I ended up overcooking it.
Saying that, I'm not disappointed with that long straight, it means in light winds, I have more fast planning area available, so although it's only 50cm wide it planes fairly early.
Your CA is definitely a different model to slowys speed boards.
