What is the best rail volume for weight?

Intresting Doggie. I have never really thought about rails compared to weight b4.
I like my rails to be sharp around the front of my tail pad back.
I have a retro styled fish that has really rounded rails that only sharpen up in the back 1/5th of the board. If they were sharper a little farther fward it would definatly be an advantage on a sucky face...

The hardest part of shaping is to get both rails even, and blended square at the same point. I guess thats what makes a good board great.

My last custom I requested my left rail to be sharper an inch forward than the right to assist my back hand bottom turns. I have never heard of anyone doing this b4 but it actually really helps. Kinda almost cheating.....

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KEARNSY said...

Intresting Doggie. I have never really thought about rails compared to weight b4.
I like my rails to be sharp around the front of my tail pad back.
I have a retro styled fish that has really rounded rails that only sharpen up in the back 1/5th of the board. If they were sharper a little farther fward it would definatly be an advantage on a sucky face...

The hardest part of shaping is to get both rails even, and blended square at the same point. I guess thats what makes a good board great.

My last custom I requested my left rail to be sharper an inch forward than the right to assist my back hand bottom turns. I have never heard of anyone doing this b4 but it actually really helps. Kinda almost cheating.....

Murray Burton did a similar thing but with the tail, by rounding off one side and squaring off the other for his back hand. Ive been running fuller round/golfball rails on my latest boards and Im liking the forgivness of them but they still give the bite required, Im 80kg 183cm. Ive ridden several other boards with low knife like rails and you have to be onto the take off with weight distubution, feet placement ect.

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KEARNSY said...

I like my rails to be sharp around the front of my tail pad back.
I have a retro styled fish that has really rounded rails that only sharpen up in the back 1/5th of the board. If they were sharper a little farther fward it would definatly be an advantage on a sucky face...

It's actually the other way around according to swaylocks. Round rails grip, sharp rails release. Thick rails float, thin rails dig. If you wanted a board that gripped better, thin, round rails all the way. Thick rails make a board feel wider due to floatation out further. Thin rails allow you to bury them deeper in a turn, but may make the board bog if you're not going fast enough.

I think Kearnsy is talking about the sharpness of the chine?

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DL said...

I think Kearnsy is talking about the sharpness of the chine?

Yea thats right, and I was talking about the actual rails between your(or mine) feet
Legion is also right.
Was waiting for you to pop your head in on this one DL what are your thoughts?

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DL said...

I think Kearnsy is talking about the sharpness of the chine?

So was I. Well, that and the thickness/foam volume. I thought kearnsy was implying that his fish could do with sharper rails to help it hold a line on a steep face, but the sways guys always talk about rounder rails holding better and the sharpness is for release (hence why it's always at the tail).

All I know is that low volume rails (regardless of chine) are better for lightweights like myself, because we don't have the weight to sink a boxy rail.

And high volume boxy rails are good for fat bastards, fat waves, learners who need some stability, or for putting a bit of volume into a board without going longer or thicker.

Never really given much thought to what the chine / rail shape really does... seems counter-intuitive that a sharp rail would release easier than a round rail. Maybe it has something to do with separation of flow around the rail and making the rail stall easier? Porka may have something to add with regards to this.

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DL said...

Never really given much thought to what the chine / rail shape really does... seems counter-intuitive that a sharp rail would release easier than a round rail. Maybe it has something to do with separation of flow around the rail and making the rail stall easier

Yeah, exactly. The swaylocks guys use the spoon analogy all the time. Turn on your tap and lightly hold a spoon. Ease the convex side into the flow and feel how the water sucks at the spoon and watch how the flow changes direction and is sucked around the spoon. Do the same with a butter knife and notice the difference. Or you could think about skimming a flat stone vs. skimming a round stone, which works better? One bogs, one releases. Of course, it's not as simple as that with all the directions of flow and movement and so on. But the consensus is that round grips, flat releases. So if you wanted to make a board for small waves and lots of slidey tricks, you could give it sharp edged, thick rails right up further up from the tail than usual. That'll make it floaty and slidey so you can bust the tail out a lot, make the board skim along the surface more. OTOH a pin tail with rounder rails will sink and hold better in critical waves.

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Murray Burton did a similar thing but with the tail, by rounding off one side and squaring off the other for his back hand.

THats sheer coincidence, Skye- Murry's son shapes my boards (Onfire) and never mentioned anything. looks like we're on to a family secret here hahahaaaa

TO clear up any confusion in my earlier post , I meant that lower,sharper rails have more bight.

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DL said...

All I know is that low volume rails (regardless of chine) are better for lightweights like myself, because we don't have the weight to sink a boxy rail.

And high volume boxy rails are good for fat bastards, fat waves, learners who need some stability, or for putting a bit of volume into a board without going longer or thicker.

Never really given much thought to what the chine / rail shape really does... seems counter-intuitive that a sharp rail would release easier than a round rail. Maybe it has something to do with separation of flow around the rail and making the rail stall easier? Porka may have something to add with regards to this.

How much do you weigh DL? Me being 80kgs I like a fatter rounder rail but not real fat, with tails regardless of type I like a bit of volume in them but in saying that I like em sharp as I can get, ive even sanded mine sharper because they were a bit blunt not that Im good enough to know but it did seem to release a bit better.

65kg...

regarding the spoon example, I just tried a spoon vs. a butter knife held at 45deg angle and the butter knife pulled a lot harder than the spoon, as well as deflecting the water further.

but if you think about it, wouldn't a rail that generates more lift, cause the board to rise out of the water more and hence slide more?

Compare pushing a water-polo ball across the water vs a kick-board. The kickboard slides because it generates lift off the surface of the water, whereas the ball sinks in.

It would be nice to be able to have boards made to test where only one parameter changes... but we can't all be Al Merrick :(

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KEARNSY said...

Murray Burton did a similar thing but with the tail, by rounding off one side and squaring off the other for his back hand.

THats sheer coincidence, Skye- Murry's son shapes my boards (Onfire) and never mentioned anything. looks like we're on to a family secret here hahahaaaa

TO clear up any confusion in my earlier post , I meant that lower,sharper rails have more bight.

Yea maybe thats where he got the idea from, thats the only time ive ever seen that type of design, how does that board go with uneven rails?
And fat rails dont sink on slow waves or a crap cutty, thats why I use them

^^^ I noticed more drive straight away on my back hand. Now all my other boards feel wierd
At the end of the day its my sytle that needs to adjust, however it definatly helps

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DL said...

regarding the spoon example, I just tried a spoon vs. a butter knife held at 45deg angle and the butter knife pulled a lot harder than the spoon, as well as deflecting the water further.

Your spoon must be broken . I've gotta admit, I'd never tried the spoon example before but those guys swear by it. Anyway, I just gave it a shot and for me as soon as the convex side of the spoon touches the stream it gets sucked right in a full cm or so. I can feel it pulling as it does it. With the knife, it just stays wherever I position it. With the concave side of the spoon it pushes away from the water, i.e. resists going into the stream. I used a standard tablespoon and butter knife.

Ok so low/sharp rails = DL 65kg and fat/round for fat batards like myself 80+kg so how about nose and tail foil or should we start a new thread?

I like low, sharp rails and I'm in the fat bastard category (~90kg).

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Legion said...

I like low, sharp rails and I'm in the fat bastard category (~90kg).

Interesting, what size is your board, width thinkness ect? I use a 6,5 x 18 3/4 x 2 7/16 round pin LSD 80kgs depending on the time of day.

^^^^6`8" x 2 1/2" x 18 1/2....custom murry burton p/d, rounded pin ...... the fins can moved forward or back bout 1/4" each way in the finbox... makes a hell of a difference if u no what i mean.....i`m ~75kg.... i dont know if this helps you much

^^^^what shape are your rails high/round or low/sharp? Its interesting what people are using.

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doggie said...

Legion said...

I like low, sharp rails and I'm in the fat bastard category (~90kg).

Interesting, what size is your board, width thinkness ect? I use a 6,5 x 18 3/4 x 2 7/16 round pin LSD 80kgs depending on the time of day.

6'6" x 19 1/2" x 2 3/8" round tail.
Also a 6'2" x 21 7/8" x 1 3/4" round tail which I snapped a while back but used to ride a lot, will ride again once I repair it.

I like the way the sharp rails dig in a turn, although I don't like the way they bog when you're going too slow (same thing in both cases, just a matter of speed how it turns out).