Take two identical shortboards ,one with continuos rocker flat bottom and one with continuos rocker concave bottom. The concave will straighten out the bottom of the board giving it more drive while the rails still have a continuous curve for smooth turns. Why would you want a flat bottom board? Besides being easier to shape ,wouldn’t there be no advantage to it?
My impressions…
Flat bottoms are very forgiving and predictable. Go good in bigger surf that doesn’t require a lot of lift from bottom contours. Smoothes out the ride compared to concaves.
Single (i assume) concaves are not added to the board without taking rocker into consideration, so your 2 identical boards should have the same stringer rocker but not rail rocker. They are separate design elements that are incorporated into a board. here are some reasons for flat bottoms:
some argue that they are faster
single concaves don't do well in choppy conditions
easier contour transition when there is vee in the tail.
better rail to rail trasition without having to go convex
now this thread is interestin9. I just finished my first proper shape after muckin around a bit with other blanks, it was ori9inally 9oin9 to be a flat bottom but the bloke I made it for wanted a sin9le concave. It certianly strai9htened out the bottom. I hope it 9ives him the drive he was lookin9 for. Cant wait for test day and to read some more input on this thread in the future from other 9uys
di99er…you trip me out with all those 9’s…ha.
…rocker should be measured along the rail line, that is before a concave or flat is considered…That’s what I reckon anyway
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di99er....you trip me out with all those 9's...ha.
..........rocker should be measured along the rail line, that is before a concave or flat is considered......That's what I reckon anyway
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yer, its 9ettin9 to me. My new keyboard is ready to be picked up and should have the car to pick it up on saturday, so hopefully from saturday forward this wont be happenin9 anymore
Ha I thought you were doin9 it on purpose:)
Spot on Yorksta !!!
When all said and done it shouldn't be one style of rocker verses the other !!!!
The trick is getting them to work and flow together not against each other
The art is shaping them and blending them as one to deliver for the style of board and wave where aiming at ....... (grasshoppers (lol))
[quote="$1"]
Ha I thought you were doin9 it on purpose:)
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No mate, Im just a cheap bu99er and thou9ht the 14 bucks could be better spent elsewhere, but no the L key is startin9 to 9o so ive caved in and 9ot a new keypad to put in.
Have to agree with you yorky , you turn your board on the rail line rocker so that does'nt change for the sake of the bottom shape. I've always thought that as long as you get your template (plan) shape and your rocker right, in other words the curves that make up the rocker rail line, your 95% of the way to making a board that works.
I don't really think that there is a right way or a wrong way to view this. after all, it doesn't matter when you add concave, just as long as you get the board right as you pictured it in your mind. It doesn't matter whether you add concave before or after, because either way you could end up with the same board. whatever makes sense for you. just makesure everything blends and flows, and that all aspects of the board(ie. rail rocker, stringer rocker, concaves, convex's, etc.) fit together in the final shape :)
Your right astevens that the final shape is the most important thing BUT the technique you use to get there is key. I would never put in a concave before I'd set the rocker and thickness.
Sparksbrand,
I completely agree with you, and I myself do not shape a single concave in before I foil and shape rocker either. rather while I am shaping rocker and foil into a blank, I am also shaping bottom contours in so that I do not end up with flat spots, or oddball contours that look like they were added spur of the moment and not completely thought out as being a part of the big picture.
I'm still not completely withn you but it's probably me misunderstanding your technique. Of course convex (something I don't use) and vee need consideration when shaping in rocker as they affect the rail line rocker, concaves however don't.
Looking back on it, I think that I worded my thoughts incorrectly. By "before", I didn't mean before I shape rocker and thickness(as that would not work), but rather that I do not shape it after either. I think that it is easier(for me at least) to think of them as separate, but shape the bottom contours, rocker, foil,etc., together(at the same time) so that I can keep track of everything, and get the board to flow nicely. A step by step process where concave is added after probably works just as well, but I guess it's just a matter of how you think of things :)
Of course convex (something I don’t use) and vee need consideration when
shaping in rocker as they affect the rail line rocker, concaves however
don’t.
Seems to me, at the point of the concave(s) leaving the tail, there will an effect on the rail rocker. Granted, lot’s of production HPSB’s seem to resolve this by fading the concave(s) @ the rear of the front fins, and lot’s of rocker right there, and some single concaves go out through the tail, and the exit is part of the tail rocker.
I fully use the exit of my “double barrel vee” bottoms as part of the rail rocker, gives a little kick/step/wing/bite on the rail at the back of the back fins.
Again though, I should make a quote as part of my signature which reads, this is just my biased opinion - even though we all know that already… Ha!
Thanks guys, yes I found my g and put a new keyboard in which is a bloody relief I imagine to all.
Back on topic, Yorky what you have said has made perfect sence to me, when I originally shaped the board I did the bottom, worked on the rocker, skimmed the deck and so on. I wanted it to be about 2 3/4 thick cause this is all the blank really allowed me to do. I was aiming at a flat bottom as great pratice on the sander to get this perfect with a level. Then my friend wanted to add a single concave. So added that from the 17 inch mark from nose running all the way down fading out a leading edge of front fins, behind the back fin there is a tiny V on purpose, just to see what happens as Im a beginner and I want to try that and next one make it flat all the way through the fins to make note of ride difference. But what you said about rocker in the rails makes totally sence to me know that Ive thought about it.
What Ive learnt is that if you are adding a rocker before hand you obviously need to take this into account with original thickness, I did not have this luxury, hey if its to light for him should be perfect for me, lol. The second thing is Im now a bit worried about the board tracking and ive really flattened out the planning of the board with the concave so should have plenty of drive, but will it track, time will tell. I always had in mind after seeing it start to come together that this would be areally nice granites board if I havent stuffed it to much.
Keep any feedback on this coming, it all makes sence and is nice to hear your guys thoughts indeed..
I’m not quite sure I understand your method.
It sounds like you shape your rocker and thickness, and then carve out more of the stringer when adding concave. Doesn’t this then change the rocker?
My method is to first skin the blank, then work the stringer area first to the final rocker. I use a rocker template to get it right. After the center is set, plane down the rail area to where I want it to end. Concave, i leave the rails a little higher than the stringer. Vee, I take the rails a little lower than the stringer.
It all starts with getting the stringer rocker perfect to the template.
[quote="$1"]
I'm not quite sure I understand your method.
It sounds like you shape your rocker and thickness, and then carve out more of the stringer when adding concave. Doesn't this then change the rocker?
My method is to first skin the blank, then work the stringer area first to the final rocker. I use a rocker template to get it right. After the center is set, plane down the rail area to where I want it to end. Concave, i leave the rails a little higher than the stringer. Vee, I take the rails a little lower than the stringer.
It all starts with getting the stringer rocker perfect to the template.
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I followed advice giving to me by someone I truly respect in the board making industry and he will always be my main point of contact when learning anything..
Out of memory, and trust me my memory aint perfect at the best of times. I got my rocker right first on the bottom, had the measurements I wanted and used a long stick to get those measurements as accurate as possible to a mm or so. I did not have the luxury of a rocker template but this is definately one of my next projects I am going to work on.... Please keep in mind that at no time in this process was I thinking of adding a concave., Once bottom done I flipped her over, skimmed the deck, cut in the rails and tucked under, smoothed her all out and finished sort of without final sand and planning down the raised stringer and all that stuff.
Once that done my mate came over and then said he wanted to add a concave to the board, so hey, I added one, this has thrown out the thickness of course but thats okay, as the blank was a cheap second, i shaped what I could see in the blank ( without sounding to hippy ) then added a concave for tim much later, I originally viewed it with a flat bottom.
No I dont believe this changes the rocker at all as the rocker is still in the rail band, that has not changed one bit, just a concave added, like what yorky said in a earlier post., remember I have not changed the rails as I finished the concave before the fins. The tiny v at the end of the tail ( around 3 1/2 inches ) shouldnt make a rats arse of difference but I could be wrong and cant wait to find out
[quote="$1"]
I'm not quite sure I understand your method.
It sounds like you shape your rocker and thickness, and then carve out more of the stringer when adding concave. Doesn't this then change the rocker?
My method is to first skin the blank, then work the stringer area first to the final rocker. I use a rocker template to get it right. After the center is set, plane down the rail area to where I want it to end. Concave, i leave the rails a little higher than the stringer. Vee, I take the rails a little lower than the stringer.
It all starts with getting the stringer rocker perfect to the template.
[/quote]
I followed advice giving to me by someone I truly respect in the board making industry and he will always be my main point of contact when learning anything..
Out of memory, and trust me my memory aint perfect at the best of times. I got my rocker right first on the bottom, had the measurements I wanted and used a long stick to get those measurements as accurate as possible to a mm or so. I did not have the luxury of a rocker template but this is definately one of my next projects I am going to work on.... Please keep in mind that at no time in this process was I thinking of adding a concave., Once bottom done I flipped her over, skimmed the deck, cut in the rails and tucked under, smoothed her all out and finished sort of without final sand and planning down the raised stringer and all that stuff.
Once that done my mate came over and then said he wanted to add a concave to the board, so hey, I added one, this has thrown out the thickness of course but thats okay, as the blank was a cheap second, i shaped what I could see in the blank ( without sounding to hippy ) then added a concave for tim much later, I originally viewed it with a flat bottom.
No I dont believe this changes the rocker at all as the rocker is still in the rail band, that has not changed one bit, just a concave added, like what yorky said in a earlier post., remember I have not changed the rails as I finished the concave before the fins. The tiny v at the end of the tail ( around 3 1/2 inches ) shouldnt make a rats arse of difference but I could be wrong and cant wait to find out