Soft vs hard rails on weak and strong waves

General Discussion
1

I started teaching my friend how to shape and of course he had many questions. When it came to rails, I found myself talking in loose terms. To clarify things, I thought I’d run this by the forum to see if Im understanding it correctly. Wave conditions and power here contextual to NJ.

SOFT 80/20 RAILS IN STRONG WAVES

Example: 80/20 full profile with no hard edge. Works well in stronger waves (150-800kj) because the water wraps around, pulling it into the face, providing hold, where a sharper rail would slide out. Low volume boards will paddle slower with this because rail area now sits deeper in the water, causing drag. However, once up and planing, the wave itself provides the power needed to lift it up higher out of the water, generating speed. Higher volume boards with this rail will be easier to paddle because the rail is floating higher up out of the water, reducing non-flat surface contact with the water. But on a stronger wave this added volume with this rail can feel less responsive. This is because the plane effect lifts even more of the rail up, prevents it from wrapping into the wave face.

SOFT 80/20 RAILS IN WEAK WAVES

On weaker waves (60-150kj) this rail can feel neutral and unresponsive because less wave energy means the board is moving slower. This lack of force makes it harder for the rail to penetrate the wave face. Adding a tuck increases speed because the water sheers out from the bottom, getting it to plane earlier and going faster.

HARD 60/40 RAILS ON WEAK WAVES

Example: 60/40 profile with formed or hard edge. With the proper amount of board thickness throughout, this rail will plane earlier in weaker waves (60-150kj) than a full soft rail would. This is because the radius that contacts the water has less height to get up on top of the water surface. It also turns faster because a sharper angle at the bottom part of the rail penetrates the wave easier than a full taller rail. This makes it more responsive and hold better on the face of a wave. But if you pinch this too much, or place it too far up, or on a rail line that’s too straight, it can hang up, feel like its tracking.  

HARD 60/40 RAILS ON STRONG WAVES

On stronger waves (150-800kj) this rail is still faster than soft rails, but can slide off the face. This is because it has less area for the water to wrap around and a rail requires more energy to penetrate faster waves.

 

2

Where’s the “Soft” 60/40 with a tucked edge?

3

I thought you were going to write that part

4

I don’t understand what you’re going for here.   Every design element involves compromises and limitations.   Every combination of design elements invovles compromises and limitations.   We have a basic understanding of most of them, born out over 60 years of contemporary surf history and probably millions of surfers.    

When someone uses the term “hard” in a discussion about rails I am not thinking of the entire rail shape itself, but about the transition from the bottom to the rail.    Is that transition closer to forming an edge or a curve?   

5

Yes, I know that you guys have a basic understanding of all the rail type, and I’m trying to get their myself. I wrote the original post to explain what I think is correct for two rail types, in hopes you could tell me if it’s right or wrong. The simple fact that rails behave differently on strong vs. weak wave types is complicated, and while you may thing it’s basic, its not always easy for others to digest at first.

6

I understand what you’re asking.  I just think it’s easier (FOR ME) to talk about how the rails will work in conjunction with the rest of the elements of a specific design than as an abstract in isolation of those other elements.   Not to mention the point that people commonly tend to favor different combinations anyway.  How do you go about telling someone who likes fat round rails that their preferred design isn’t as good as another combo, or that it’s “wrong” for what they’re trying to do?     

Here’s the truth of it - when it comes to design there’s better and there’s worse, but even “mistakes” can be fun.   Even making a “mistake” can lead us in a new-to-me and interesting direction.    There’s nothing wrong with making a mistake so long as you can figure it out in the end.   

If you’re relatively new to shaping then watching what other shapers have been doing for whatever type of board you’re working on will provide you with a good template to work from.   From there any changes that you’d be making would be small and would have a reason in support of making it.    Small changes can often have a noticable effect.   

7

I’m not any good at writing them, but I can shape 'em.  

8

I think, as with most all things, personal experience is the only real teacher. So somehow, a way must be found for that person to test ride (a number of times in a variety of conditions) whatever you would recommend for them.

9

Yes, Im a huge fan of the iterative design process, and testing it in the water is the most revealing, But surely there must be a more comprehensive understanding of how rails behave? So far I’ve found a few pages in Orbelian’s book and snippets scattered throughout the archive on this site. Im trying to put them together in a way that makes sense. 

10

Likely there’s a lot written or available via oral transmission from skilled shapers. But still, it’s like trying to tell someone who’s never tasted one about the taste of a fresh strawberry.

11

As I keep saying, it will be easier to respond to what’s going on with a design consisting of multiple elements than to opine about which rails to use in strong vs weak conditions.  Especially when we can’t know what you’re trying to do.      Having a forum where people can swap opinions is a nice resource but it’s no substitute for surfing a board to see how it reacts under YOUR feet in YOUR local conditions.     

12

Bingo !

13

1

14

The terms 80/20 and 60/40 are vague and largely obsolete.  For performance shortbaords, we migrated to very thin boards with minimum radius rails about 1/4 century ago.  Having the thin rails, especially up in the nose, gives the board that fine edge feel.  With domed decks, the round rail wraps until it meets the deck.  There is no 60/40 or 80/20.  A boxy tucked edge in back keeps things from catching.  We’ve migrated that trend into big wave boards - today’s guns have rails that look more like shortboards rails did 30 years ago.  Traditional longboards remain unchanged, but the thin trend is migrating somewhat into performance longboards.  And riding those performance shortboards isn’t limited to small waves - charging 3x Hawaiian juice on a thin 6’ 4" is common.

So, why would we need rounder rails?  Forgiveness.  Softer rails are easier to ride in bumpy conditions.  Softer rails are easier to ride for the average surfer.  Bigger people need proportionately bigger things, so big guys get big round rails.  So on and so forth.

I can’t give you the answers you need.  My suggestion is to take a carpenter square and do a survey of rail radius at 1/4 length from the nose/tail and the midpoint on every board you can get your hands on.  Compare that to general template and thickness dimensions of each board.  In time, you’ll have a design database.  Then train yourself to identify the different features of a board at first glance while you are at the beach, then watch how good/bad that board works in the conditions of the day.

15

Is the OP talking about shortboards or longboards?

16

I think your observations/opinions are basically sound.  I think you should also consider quantitating the overall thickness of the profile and most importantly, how and where the thickness tapers from end to end (foil.)  You are hitting it with your comments on “pinching” - too much or too far up and you can indeed introduce a tracking tendency.  I’d go so far as to say that rail specs on a custom board are easily one of the hardest details to convey to your shaper.  Personal preferences are easy enough to identify when you’re riding that favorite board on a good wave - it just feels right.  The problem is that everybody has their own specs that work for them in certain waves.  “Soft egg” or “hard down” make enough sense to you as you are describing them but a lot can get lost in translation.  I know some good shapers who use foam rail templates - nose, mid and tail as they foil out a board.  Other guys use rail contour gauges or maybe just grab the rail with their hands.  Here is an idea you might consider for measuring rails:

 

17

Yes, I understand that everyone has their own methods and yes, I own a guage like that too. However, it’s hard for me to believe that generalizations can’t be made for rail design. If all of this was so wave-dependant, then how could a Ph.D like Terry Hendricks write Surfboard Hydrodynamics, or our Aerospace Engineer membber, Scott Jarret, derive a single value to represent rocker targets? People are talking about waves as if water behaves differently across the world. Now Im certainly not as experienced a surfer as many of you here, but I’ve stood on enough of them across Puerto Rico, Maui, El Salvador, to understand they can all be classified into categories, and measured with energy ratings, to know that there are simialrities between those waves, and the ones I ride weekly here around NJ.

18

Everything else being equal, soft will ride lower and stick, hard will ride higher and release.   

The thing is, these elements don’t just work on their own - their effects are in conjunction with the other elements of the board.  And the rider’s stature and what the rider is trying to do with the board.  Curve in the template, curve in the rocker, widths and thicknesses - it all counts.  

That’s why we keep asking you about your overall design and what you’re trying to do.    

 

19

You’re exactly right, water is the same everywhere.  What we see is that the same basic shortboard is made and surfed everywhere in the world from two foot slop to double overhead juice and bigger.  Hawaii shapers tend to put more tail rocker into their boards, but not really that much of a difference to where one of those boards won’t work well anywhere else in the world.  Larger fins will be used for the North Shore, and then slap in something smaller for Sebastian Inlet in Florida.  The big difference that your region offers is 35°F water in February.  As good as 21st Century extreme cold water surfing wetsuits are, all that rubber weighs a bit, it retains some water, which adds a bit more weight, it takes some muscle to bend it, the cold takes away some of your strength, so you need a bigger board underneath to compensate.  Throw in some 20°F 15 kt. side offshore winds, and you have an extremely challenging session that Mexico, Australia, California, Hawaii, Florida, South Africa, Portugal et al will never offer.  My general thought progression is to first add width, then thickness with a bit of softening of the rails, then add length.  Most folks only go longer as a solution to this problem.  So, say, if you like riding a 6’ 4" x 19" x 2 1/4" in trunks in ideal warm water waves, then maybe a 6’ 5" x 20" x 2 1/2" would be good 1st design iteration for when rubbered up for the cold.  It’ll still be a shortboard, that added inch of width will make it soooo much easier to catch waves, and the little extra thickness combined with the volume of more width will compensate for the added weight.  Then again, I’ve read articles and seen accounts on YouTube of guys fully rubbered up surfing Iceland on their standard shortboards.  So what do I know.

If you’re riding fun shapes and/or longboards, you already have sufficient volume and width to deal with all sorts of adverse conditions.  As for the rails, they’re failry soft and shaped pretty much the same everywhere you go.  I don’t think anybody is changing the rails for different conditions on those designs.

I did a single-fin project a couple years ago.  The idea was to make a modern board that looked like a 1968 performance single fin.  So it has a pointed but blunt nose, a square tail, is 6’ 10" x 21 3/8", but is thin at 2 1/2" with thin rails.  The rail radius at the wide point is 1/2" and at 1/4 length in the nose is 7/16".  The rails in the tail are modern tucked and boxy.  And it has my rocker.  It’s a perfect marriage of the two eras.  The thin rails easily slice into the wave to provide that sublime fine edge feel, and that is combined with that amazing single-fin drive.

I did a thruster mini-gun project in ‘92 or so.  It’s 7’ 0" x 18 1/4" x 2 1/2" (I weighed 50# less at the time).  The rail radius at 1/4 length in the nose is 13/16".  Yes, a super soft 13/16" on a silly little 7’ board - not a 9’ gun.  The wave I was trying to get down is exceptionally hollow wih frequent rip, seawall backwash, eroded beach backwash coming up the face and then chop coming from the other direction from the prevailing outer waters westerlies.  When other folks were scratching to get out of the way of one of those beasties, I was able to paddle into them.  So again - soft rails for forgiveness.  The soft rails will ride over the bump, whereas thin rails will slice into the bump and get hung up.  When not riding beasties, the board was a bit of a pig.

20

Come on man;  Water is NOT the same everywhere.  Some people will believe anything.