Quad + 1

General Discussion
1

Hi all,

I’m shaping a board for my girlfriend, things are coming out not too bad. The dims are 8’0’‘x18’‘x21’‘x14’‘1/2x2’'3/4. I’m making this board for her to have fun in the small summer waves.

I’m done with the shaping and now considering the difficult question of fins placement. I know that it’s a really popular question here on swaylocks and as a good newbie, I’m asking you about fin placement.

Picture of the outline:

and the rocker:

I have 4 Lokbox boxes and a center 10.5’’ box. I was considering a quad + 1 fin system to be able to play with different configurations.

Any experience with that configuration?

I was going to eyeball the quad placement but if anyone has some numbers or general idea, it would be greatly appreciated.

Thanks,

Pierre.

2

I have one at home I can measure for you, but it’s not an 8 footer, so lemme know if you’re still interested.

3

Yes, I am!

How does it work?

I’m going to route the hole for my center fin box at 5.5’’ (I plan to add a tailblock).

First time placing the boxes under the lam, I’m a little bit afraid to ding the freshly shaped blank

4

Etmo,

Actually, my time schedule was quite a bit tight and I made it this afternoon, but I’m still interested to compare if you have some numbers.

Here is a picture of the result:

Roughly the rear base of the fins will be at 1.5’’ of the rail. I don’t really know for the toe in.

Pierre.

5

Mckee is a shaper who has done some tremendous work on quads, and has provided the exact formulas for fin placements, and includes info on fifth fin placement as well.

His formuals are found on the following link:

http://www.mckeesurf.com/brucemckee/multisystem.htm

good luck!

6

Hi Pierre,

I guess it’s too late, but here’s the board:

The tail width is 15 3/4", the rearmost point of the 10" fin box is 6" up from a line drawn between the pins.

The front boxes are 14 3/8" up, 1 inch off the rail, and toed 1/4" inch.

The rear boxes are 7 1/4" inches up, 1.5" off the rail, and toed 3/16".

This fin config works great. I’ve ridden it as a single, a twinzer, and a quad.

Hope that helps…

7

That’s tidy looking number. Was it EPS?

8

do you own that Craftsman?

9

Wow,

I was not able to check Sways for a long time and I’ve been pleased to see that my post got out of the grave.

I guess I owe you a short update about the board:

Here are a few pictures:

lam preparation:

the bottom (crazy stripes attempt):

the deck:

So, this board was for my girlfriend, she likes the design a lot but she decided my board was better and she surfed mine all the time. I surfed this one as a single fin only. Didn’t have the time to experiment with fins combinations. The board rides good but is too light for me and doen’t float me enough.

Pierre.

10

pierrel, I would say, You have a good eye for placement. Nice job. Mahalo,Larry


11

That board reminds me of the one Dennis Ryder showed. Any chance of some more pics?

12

Hi deanbo,

This board was shaped by Steve Irvin from HB. I have move pics of the board with different fin set-ups, but not the whole board. If you like I can show this boards multiple set-ups.

Mahalo,Larry

13

That would be good, thanks Larry.

14

deanbo, Here’s Steve’s board set up as a 2 plus one with a 7 1/2" center fin with 3 1/2" side bite sets set at 6 degree with Anti Drag Floater Plugs in the back 2 ProBoxes to zero out the weight of boxes not in use.

Mahalo,Larry

www.ProBoxfinsystems.com

15

deanbo, Here’s Steve’s board set up as a Twinzer. Take notice of the center channel has a filler plug so no exposed slot to worry about.

Mahalo,Larry

www.ProBoxfinsystems.com

16

deanbo, Here’s Steve’s board as a Quad with 6 degree front 5 1/4" fins, with 4 degree 3 1/4" rear fins.

Mahalo,Larry

www.ProBoxfinsystems.com

17

Deanbo, Here’s Steve’s board with 7 1/2" long Keel fins with Anti Drag Plugs in the other ProBoxes not in use with a center plug for the 10" center box.

Mahalo,Larry

www.ProBoxfinsystems.com

18
Quote:

deanbo, Here’s Steve’s board set up as a Twinzer. Take notice of the center channel has a filler plug so no exposed slot to worry about.

Mahalo,Larry

www.ProBoxfinsystems.com

Nice plug in the single fin box Larry.