Firstly Id like to give a giant thankyou to all those kind and skilled people on this website that have shared their knowledge. I am new to posting on Swaylocks but have been using it as a resource for a few years and Im not sure where Id be without it! So, thanks.
Anyway Im in the middle of shaping a 9’6 noserider for a friend of mine and need a little help. Ive never actually shaped true 50 / 50 rails. Im using greenlights “rail dimensions guide”. I converted all their measurements into fractions and buy my reckoning the " rail mark " ( mark up from base on rail ) would be 1 7/8. Im using this mark to plot my rail bands John Carper style… With this measurement it would seem very little is taken off the actual rail diameter and would leave a massive boxy rail. Did that all make sense? Basicly im looking for any experienced help on shaping 50/50 rails… Bearing in mind this is only my 11th board. And first noserider… Thanks so much.
Your conversion is wacky…what is this 1 7/8 thing? You don’t tell us how thick the board is? Your board might be 2 1/2 thick …or it might be 3 1/2 thick? Shit it might be 4 in thick…Anyhow, just count your passes on the rail…3 on top…3 on the bottom, or whatever looks right, just keep track of the passes…take your time… The big trick is if you want them thick or pinched.mthere are quite a few different 50/50 rail set up. A true 50/50 is equal on top and bottom… By the way I’m not a fan of 50/50 rails, way to old school. Better at 60/40 and slightly pinched…IMHO.
You dome the deck…what’s so hard about doming the botom? Really. same process…Rolled bottom / 50 50 rail…same top and bottom…Vee out the back…Too much overthinking…flash bang ram bam thank you mam!
the dome on the deck is considerably more than the bottom, if the rolls matched, the board would just wallow on the wave, the rails may feel like 50/50, but looking at them on edge you can see it it more like 60/40, a much livelier ride
I was thinking the same thing as Jim. 50/50’s a term that oversimplifies and doesn’t take into consideration deck and bottom contours. And a nice rail line has smooth and deliberate transitions.
I’ve always preferred the term egg-rail , to describe the rails on an old log…or as Peter Drouyn once explained to me “they are like the sharp end of a watermelon”… still , there are quite a few older vintage boards that had more roll on the bottom , than on the deck .
Without going in to the advantages and disadvantages of a “true” 50/50 I will add a couple of diagrams that might help. I don’t think I’ve ever seen a board with “true” 50/50 rails. Most boards with 50/50 rails transition from 50/50 to something else somewhere along the length of the board. In my experience, that’s where it can get tricky… the blending of the transitions and keeping everything symmetrical. While sighting down the length of the board with the bottom up, trying to eyeball the rails on both sides and making sure the rocker and cross contours are accurate is difficult and takes practice.
On these diagrams, don’t look at it like it’s your pattern… it’s just an example I drew up as a reference. The rail profile is just to compare “true” 50/50 rails at different thicknesses. The contour gauge shows a rail that isn’t 50/50 but shows what might be called a pinched egg rail… kind of like the pointy end of an egg vs the fat end of an egg.
Most shaper banded rails, matching the bands on both sides for angle and taper, then blended them into smooth matching curves. Not Iggy. He curved the decks down to about a two-inch square on the sides that represented the outline. Then he took ahold of the end of the board, lifted it from one end and began rounding one rail, front to back with a sureform, then went back to front on the other side. Did each complete rail separately. Sanded it out, screened the rails. Viola! Done. I’d never seen it done so fast and easy.
This modest statement has always rung true for me…
Iggy again,
“Bra! Don’t make problem where no is.” He was a true classic, and a good surfer too. –S.P.
Geometrically speaking there are two ways (at least) you could define what is a 50/50 rail (the way I understand it anyway).
The images below both show the same deck roll and bottom roll (bottom roll is less than the deck of course) with these two variations of construction. The dimensions shown are for comparison purposes only.
The first is a rail which has a single uninterrupted radis which is tangent to both the deck and bottom. But as a result its midpoint is not the extremity.
The second is rail at which the midpoint is the extremity and the radius above and below are tangent to each other and the deck and bottom as well, but differ in value.
The last image is the two constructions overlaid so you can see the difference.
But as you can see, neither of these look particularly “sweet” and as the wiser and more experienced heads here have already commented, the typical 50/50 rail definition is indeed an oversimplification. But what I’ve shown maybe a good initial place to start if you are really looking for a pure 50/50 distribution of volume in the rail section - then properly blend and lead in everything until it finally looks and feels right. It would seem that a true 50/50 rail never gets made because they are indeed too bulky and end up getting refined until they suit.
Please also bear in mind that I have only shaped a handful of surfboards as opposed to some of those who have already commented on this thread whose shaping experience numbers in the tens of thousands of surfboards. Just thought some diagrams might provoke some further discussion so that I might end up learning as well. And I will be happy to stand corrected if my basic “theory” detailed here is considered erroneous.
Gene, Bill, Jim , John, Resin, Kayu,Matt, RD, Huck…
Your board building is awesome… I did a few passes on the top and a few passes on the bottom. I see the rolled bottom 50/50 rail as simple. But in the real world I just buy a great blank and follow the curves… I like the 9-9B from US blanks…I got sick of the HP longboard thing and made my own boards…good or bad ??? They work for me…Stingray.
When making surfboards, the journey is as important as the destination, to many folks. Me among them. That said, no matter how much you enjoy the journey, it falls a little flat if the end result doesn’t live up to your expectations. There are many paths to a successful surfboard. If you meet, or beat your expectations, that’s all that counts. There are many surfboard design breakthroughs, that were the result of a ‘‘mistake’’ in the process. Keep on, keeping on.
With your blank at thickness and just short of final sand and screen; Find the middle of the rail. Mark it all the way around the outline with a simple pencil line. Determine how thick or pinched you want the rail to be. Mark a second and third pencil line above and below the center reference line. Depending on the desired “pinch” the 2nd and 3rd line could be 1/2-- 1" above or below your center reference line. Cut you bands using the 2nd and 3rd line as the starting point. Blend onto the deck and bottom. Maintain the center. Once you have blended onto the deck and bottom; blend the middle into your bands. Nose and tail are are fine tuned to follow the 50/50. Very little measuring and over thinking. I know that’s not in the spirit of Swaylocks, but it has always worked for me. Rarely do you see a 50/50 rail with a steeply domed deck. Primarily because they surf for $#!t. 60/40 is much better. Depends on whether you want looks or performance. Lowel
…I think some of you have a confusion about the relation of deck and rails (the curves)
You can do a 50/50 rail with the SAME type of deck than a 60/40 rail…so you can do a rounded full rail with a FLAT deck too
The 50/50 s are pinched or like that in the tails area due to the rockers and thickness but still are 50/50s
In the nose many times are 80/20s.
60/40s are more high performance oriented rail but the rounded rails are very good down the line or when you do not need edges; the problem is that you lose speed and they grab too much.
The round 50-50 rails get a bad rap here, and I’ve never shaped them myself, but seems to me I had a Walden Magic 9-6 that had those fat baseball rails, and it worked pretty good. Lotta other stuff going on with that board, 'tho, as regards the bottom shape. I sold it to a friend who went through some hard times (can you say rehab?) and never paid me a cent. I said look, just return the fin and forget about the money, you can keep the board. He called a couple weeks later to say the fin was stolen. He’s clean and sober now 'tho, so I don’t have any bad feelings - just kinda miss that board!
My definition of a 50/50 rail is just one in which the apex is in the mid point of the rail. Not symmetrical at all from top to bottom, as the deck contour going into the rail is far different as the deck foils from nose to tail.
