Nose Rocker Design Question

General Discussion
1

While surfing a shore pounding hollow beach break, I noticed that after

making the drop backside into the pit, the tail wanted to drift out,

almost like it was finless.

I have another board almost identical but it doesn’t have this tendency.

There are some subtle differences, but mainly, its nose width and

nose rocker. Fins, rails, thickness, tail rocker are all identical.

The “problem” board has slightly more nose rocker – 6” versus 5 ¼” –

than the old reliable. Its rocker, since it is greater, extends a little

further back toward the tail.

Part of the problem might (almost certainly) is me. On by backside

take-off, I am extremely front legged. I tend to crouch almost

completely over my front leg, with a rear drop knee stance. I end

up putting all my weight on the front of the board. This is great for

getting down the face, but causes the problem at the bottom. No

weight on the fins, so they tend to drift out.

What I’m thinking is, if I push the apex of the nose rocker forward,

and extend the flatter area, would this help? The down side is the

nose rocker would be steeper. What would the trade-off be? Steeper

nose rocker would paddle slower, but longer flat spot would paddle

faster. Once up and riding with the nose rocker out of the water,

would the flat spot make the board too stiff?

2

IMO only, here’s how I see your situation.

I think you are over thinking the problem. You

had me at “fins washing out”. I’m a front foot

guy on my backhand also, especially when the

waves get hollow. My solution to the same feeling

was to adjust my fins. I often surf Lokbox and on

those boards I’ll move my inside fin on my backside

back to engage more after the drop. On my boards

where I use futures I go with a larger inside fin by

about a 1/4" on base. If I’m running a JC or Merrick

4.5" set, I’ll swap out that fin for a 4.65" side runner.

Adjusting nose rocker is not a solution, as it will also

affect wave catching, front side surfing, etc. You are

correct IMO in breaking down the rocker into three areas,

namely nose, mid & tail. Usually it is not the end measures

that are critical, but the acceleration these curves make

that is important. I usually don’t compare nose rockers

on my personal boards, but the differences between the

acceleration in rocker at 6", 12", 18" & 24" from the tip.

You didn’t say what size board you were riding, so my

advice is based on a standard of something around a 6’2"

or so. I would be looking at a board with numbers around

these: N = 5.35", 6"=3.0", 12"=1.74", 24"=.45"

Tail = 2.38", 12"=1", 24"=28"

I use design programs to look at the curves which is why

they are in decimals.

One other hint; if you are shaping your own boards for

[=1][ 2]a particular wave (we have a super barreling “secret spot”[/][/]

[=1][ 2]wave here in OC that breaks about once a year) you might[/][/]

[=1][ 2]want to put a bit of vee (or increase what you have) on your[/][/]

[=1][ 2]inside edge/surface for your backhand. I’ve used this trick[/][/]

[=1][ 2]before and it works well and I didn’t feel any difference on[/][/]

[=1][ 2]the frontside.[/] [/]

3

You should look at a Greg Griffin. They have flat rocker in the nose and tail, almost symmetrical, except for the first foot of the nose. Same thing as Pavel’s, just less extreme flip. At least the ones I have seen.

I think that the vast majority of nose rocker should be in the first 1/5 to 1/6 of the board.

Pavel told me once that most blanks have symmetrical nose and tail rocker if you cut off the first foot of the blank.

Also, I don’t think that the front 1/3 of the board has much effect on stiffness. Those design aspects that effect the ability to turn (rocker, template curve, tail width, fin setup) are in the tail.

4

I think you articulated your problem: too much front foot pressure. You want to shift your weight to your back foot coming off of the bottom anyway. If you’re standing up with your front foot first, which makes you get in a drop-knee stance, then you need to correct that first thing.

As far as fixing your sliding out problem with your board design, I’d also recommend bigger fins. I know if my fins are too small from sliding out on backside bottom turns (rarely)/frontside cutbacks (more common).

I agree with the previous replies in that the nose rocker isn’t your problem.

5

Well, I guess the good news is I don’t need make another board!

The bad news is I have to break a 35 year old habbit. = -0

6

This is one of those things that throw a lot of shapers, how to get enough lift in the tip and not move the apex of the rocker under the middle of the board.

I recently shaped 2 boards, racy longboards for large surf, the first 10’2" and the 2nd 9’0", both are off the same bottom rockers, lots of nose lift and a good amount of tail rocker.

The extra thickness of the 10’2" caused the deck to be distorted, but I kept the bottom fairly straight under the front foot, once the tail and nose are thinned out I still wanted the central planing area.

I thinned it out close to the tip of the board, this kept the curve very forward, allowing for an entry rocker that was not extremely bent behind the nose.

But the nose is thicker behind this flip, the remedy for this is crown the living crap out of the forward section of the deck, dropping the rail line lower along the entry.

It almost seems like you are winding up with a lot of your weight over the front portion of the board, lifting the tail and fins nearly free.

I had 2 boards with a lot of cant on my fins, at high speed on the drop, when I hit the flats, my tail would get real squirrely, I think I was getting too much lift.

As much as you think the 2 boards are identicle except for the nose rocker, there may be much more that you’re dealing with than meets the eye

7

So Jim,

Are you saying that it is better to keep the rocker a little flatter under the front foot,

and put most of the rocker curve in front of the front foot.

I took carefull measurements of the two boards. The one I’m riding in my avitar has a

flatter area under my front foot. It rides really well, but a late drop is a little sketchy.

In the second board, (the one with the drifting problem) I brought the rocker curve a little

further back, and made it a touch higher. That fixed the drop-in problem, but it does paddles

a little slower, and it has the drift.

Next time out, I think I’ll play with the fins. Maybe put the FCS Occy in the front, and keep the

FG 7 in the rear.

8

If the newer rocker had been kept the same for another 10 inches or so, then lifted to the present tip height, I think you would get in easier and avoid the late take-off jitters.

Most of the surfboards manuevering is from between front and back foot and uses the bottom, fin and rails of this area to supply control and power.

The forward portion is how the board negotiates oncoming water and delivers it aft, with the purpose of keeping the nose from being under water.

You all see how critical balance and trim is in your surfboards, all you sometimes need is to readjust your center of weight by a half inch and the boards immediately paddles much faster.

Everything that gets done has its trade offs, it is finding a happy medium where the components are compatible with each other and in the end having a surfboard that is easy to ride and gets the job done without multiple personality disorder

9

this is the kind of info from experience that i hope to find on Sways.

thanks for posting up the question everysurfer.

please continue Jim, i for one am listening.

10

I think it might have a problem with thickness also. I looked at some pictures from

last summer, and I remembered that if I positioned myself correctly to land in the

sweet spot on the take off, it paddled with the nose up in the air.

If I scooted forward to paddle faster with the board more level, I landed

too far forward, and the tail drift problem. I was thinking a fix would be

to change the nose rocker to get the tip down.

Maybe If the middle of the board was a little thicker, I could position

myself a little better.

So many variables!

Thicker with the same rocker?

Flatter mid section, with steeper nose rocker?

Maybe a little of both?