Specifically, what would happen if you left a rail looking like half a stop sign (cross section). I’m not considering this, just curious. if one of the hydrodynamics gurus wouldn’t mind giving this noob a layman’s explanation, it would be much appreciated.
I know a guy who leaves the edges on his rail bands and swears by them.
If the overall volume is OK, it probably wouldn’t be much of an issue and the board would probably work OK. It’s possible that a top edge might cause a sunken inside rail to hang up on rail to rail transitions but maybe no more so than a thinned out rail might.
I view the top portion of a rail like I do the outside surface of an outer fin… a domed surface is likely going to allow a sunken rail (or fin) to ‘break free’ more easily and enhance the ability to perform those rail to rail maneuvers mentioned above.
Simply put, water adheres to a curved surface, and looses its adhesion at abrupt changes, and corners. Your rail is a huge part of generating forward movement. A big thick round rail will project you further forward in a turn than a thin edged rail would. So a rail shaped like a stop sign won’t project you forward very well through a turn.
I used to do a few boards where I left the lines of railbands. Usaully 3 on the deck and one on the bottom. This was in the 70’s beak nose single fin days. Harder to sand. Seemed to work OK . Looked really good when I did white opaque glass jobs.
ham385, try it and let us know how it works. Experimentation is the best way to get clear results.
Bodyboards seem to do alright with straight, faceted rails. It’ll probably work OK and you may stumble on something really enlightening.
There have been many hollow built craft , including surfboards that use flat panel multi-chines with very good performance. One distict feature is speed , due to the length of releasing edge. It would be difficult to declare it better than a blended foil…that would depend on the overall shape , and how it was designed and put together into the final board…it was common practice in early solid timber boards and hollw plywood constructions. For structural reasons hard edges need to be strengthened to resist the increased impact because of being a constant high point…similar in principal to fenders or boat gunnels.
Most of the time (when you are up and planing), the only part of the rail that is doing anything is below the apex. Water deckside of the apex has been displaced and if it actually touches the deck has little if any affect on the board’s performance . I doubt you would feel any difference. A faceted rail below the apex is a different story. Bob McTavish has played with them a lot and found them “interesting” but a lot of work if done by hand.
I’m betting that the rounding of rail bands is a way of covering up wavey, uneven cuts. It is for me anyway. Probably more work to get them perfect than it’s worth.
Seen it a few times over the years… During the transition era in the late 60’s I think it was Con came out with a “hard chined rail” - which is what you’re talking about. Think he called it the “Iron Butterfly” model.(“Ina Gadda Da Vida” was on the 8 track at the time…). Later, in the longboard resurgence, believe maybe Stewart and/or Walden tried some hard chine rails…
Like a lot of things experimented with on boards - some few may have found a benefit but not enough to alter the arc of getting us where we are at.
The cool part is that the arc has yet to come full circle… So who knows…
What goes around comes around ??
Saw a Stewart in the surf shop just today with the chime rail. And saw a couple firewires with a steep chine in the front half just like if you didnt blend your rail band on the bottom side. Aesthetically it looked funky to me, but no idea the design philosophy.
Leaving the rail bands has been done throughout surfboard history.
I think it looks cool.
Kinda Geometric.
Been doing this model with a “Chined” lower rail (Ben Aipa) and beveled nose and tail.
Sanders love it!
HAHA!
No they don’t.
Yeah didnt mean the chine looked funky, just the firewires cuz they beveled the nose chine real steep like 45 degrees. Might work great tho I don’t know!
In my experience too much hard edges in the wrong places cause boards to track and negate the turning effects of the fins. I have not had a chance to quantify this and it was just a personal observation especially in large steeper waves.
My two cents.
D
Hard edges can work as a release for water exiting the surface of the board, but they can also create a lot of drag on the leading edge moving into the water.
Yes indeed.
Water releases off sharper edges more efficiently .
Less or rounder edge sits slower in the water.
More drag.
Stewart and Slick have been using this rail on Long and Short boards for a very long time. I have ridden his(Stewart) longboards back in the 90’s and let me tell you a 9’0 HP Stewart long board with a chine rail Is one of the best and most versitile boards made. Does it work on every design/template?? No. And: The bottom rail is where it counts. If you want to leave three or four bands unblended up on the deck and you think it looks “Cool”; Then go ahead on. Just don’t figure on anyone ever buying a “but ugly” board from you… Lowel
I’ve tried some chines, and strakes… Freakin’ fast combo.
Recently tried chines in the nose quarter on a big gun, to try and deflect spray from chop, and for release from said chop on drops… Can not say I noticed a difference.
“Looks schmooks…”
“That was particularly harsh…”
I think it was sharkcountry or oneula was threatening to build a board and leave the rail bands un-blended. If you eased the edge a little between facets on the deck side, I think it would look pretty cool. McDing is probably right about being hard to sell, 'tho, just cuz anything outside the box can be hard to sell. But I don’t build 'em to sell, so if someone could talk me into it, I might try it one of these days, just out of curiosity. Be easiest to do it on a wood board, because re-shaping would be easy-peezy if I decided I didn’t like it.
I made a little board with a really hard down rail (a little bit like some of the MR twin rails) all the way up, and it is really fun. It looks like crap but man does it ever skate along fast. It’s a really low-rockered 5’6" quad, and you can really feel the difference in that the rail releases all the way up the board, which makes it squirrelly on bigger steeper waves. But once you get your back foot finessed up to the peculiarities of it, it really is fun especially on sectioning points (I had a lot of fun surfing it in Peru at places like Chicama)…
But they take getting used to!
Another thing to try…