Just shaped a mal for a mate who wanted a board he could have some fun on. I don’t surf them but he really wanted me to make him one (silly of him I know). It’s 9’ x 22 1/2 x 2 3/4 and I’m quite happy with it. I intend to put a fin box in for him with some side bites. Years ago I took some measurements off a McTavish and was just looking at them and they seem quite radical (ie back of fin up 18 3/4") with a heap of toe. I couldn’t start laminating without asking for some help re their placement. I’ll be using FCS. Is there a standard that most guys work off similar to a thruster? I tried the archives but couldn’t see anything. Thanks for your help.
I’m interested to hear some opinions too. I’m shaping a board right now with those exact same dimensions. I’d like to put some side bites on but I’ve never surfed boards with them (this one is for a friend) so I have nothing to look at for help. I’m planning on using Probox though, but some advice on cant would be helpful too.
Here’s a not-very-scientific method:
Make cardboard copies of the sidebites that you plan to use, and with tape or clay, move them around until they look like they’re in the right place. Go away, come back a bit later and look again, and so on. Intuitively, you’ll probably arrive at a good setup for that board. Mark the spot, then, take a square and make proper marks. I don’t toe-in side bites much- 1/8’’ or less, and use very little cant.
Also, I like these little one-tab fins. We’ll see how they hold up
wow, without knowing the details of bottom contour or a rocker shot, it will be pretty hard to get it perfect.
I’ll take a stab at it for a couple of scenarios with your given dimensions.
For a typical performance 2+1 longboard (mal, or malibu) I will put the side fins at 15-1/2" up, and 1-3/8" in from
the rail, pointed along a straight line that exits about 1" off the nose (exit point same side as side biter). Using
a 10" fin box, the rear edge of the box is right around 5-1/2" and the fin sits about mid-box depending upon the
depth of the fin.
If the Mal is more radical, the side fins go up further as does the center box. That is, more tail kick, move up
the fin set. BUT, bottom shape will also come into play (as does the template and tail width). If there is a lot
of Vee exiting at the tail with moderate rocker kick, the fin set would also go forward a bit.
Exceptions are everywhere. Specialty longboards for a specific point break may use a totally crazy fin set up.
In general the numbers above will yield a good result.
HTH,
George
I’m interested to hear some opinions too. I’m shaping a board right now with those exact same dimensions. I’d like to put some side bites on but I’ve never surfed boards with them (this one is for a friend) so I have nothing to look at for help. I’m planning on using Probox though, but some advice on cant would be helpful too.
Hi Rachel, Great to see everyone enjoying the surfing lifestyle. In answer to your question about placement and cant, there’s a rule I go by especially when you have adjustabilty for side bites. That is, the back of the side boxes using ProBox has a example is that the back screws in the ProBox should line up with the front of the center channel. This gives you the ability to tune your fin placement with the leading edge of the center fin to the trailing edge of the side fins. As for cant, 4 degree insert would be my choice to start with. Hope that helps Rachel? Please feel free to ask more questions. Mahalo,Larry “Have a Happy New Year and Welcome to the ProBox Movement”
I would normaly go along with what Probox Larry says, but every board that has different lengths, width’s, contours and rockers would lead me to think that various fin spreds would need to be considered
When I did my ten footer I was advised (By someone else) to spred the fins out
I think it was about an inch from the front center box to the rear of the side bites
I will check later cause Im ill right now
I was skeptical and had slid the fins as close together as possible
The first go out was a mushy place and I didnt notice anything odd
but when I went to some juicy 5 to 6 ft I noticed some major oversteerage
so I moved the side bites forward and the center fin mid box and wow what an improvement
The board now is melted with my mind insted of it having a mind all its own
conclusion… if the fins are all lined up you get over stear
if there spread apart you get the stability of the torque of fin against fin
Hi Chriss!
plusss one is right on the money.
however all my boards (not ones i’ve shaped) have had the side plugs around 18" up… even a tolhurst had those dims. the mctavish i’m guessing was a pintail? the pintails i’ve used all had there plugs/boxs a couple of inch’s further up.
okay so now the usefull bit
i have ridden and had heaps of fun and performance on mals with there sides 18" up.
but plusone is right.
Hi Rachel, I forgot to give you measurements, but after seeing the other post, PlusOneShaper is the measurements I would use. If you look at the pics in my first post, the side fins are placed after the postion of the center box. And by placing the center box 5 1/2" from the tail the side fins would be at 15 1/2" with still a 1/2" of adjustment. And because of the foreward and back adjustability in the ProBox you will not have a problem in finding the proper spacing with the center fin and the side fins to your liking or similar to allangibbons placements. Kensurf is right on a bigger board the side fins need to be alittle more forward, like the Red Longboard in my first post to the left, those front side fins are 17 1/2" from the tail with a Quad option(like the pic below) or moving the side fins to the rear box for a 2 plus one with the center fin all the way back in the box. Have fun Rachel. Mahalo,Larry
Thanks Larry! Once I get the blank down to the perfect thickness in the tail I’ll take some cardboard templates and try out a few different placements. I usually put my center boxes around 5-6" up from the tail so 5 1/2" sounds perfect.
Quick question. Do I need the new install jigs and router for the new boxes? I have the old install kit and when I saw that you guys had changed a few things I was wondering if I needed to get the new kit. I like the changes you made though, I had been having problems with resin getting in the screw holes and it looks like you figured out a great way to fix that.
not about placement, but a very useful tip that Plusoneshaper gave me is to glue the sidebites
on to the board with a dot of superglue before glassing
Rachel, Yes you need the new jigs. Please PM me your shipping information and I will take care of that for you. Mahalo,Larry
Thanks George and to you all for your advice. I will go with these basic measurements as they looked pretty good to me (now that’s scientific but at least you have the experience - that’s why I asked) when I marked them on the board.
Allan, I realise there is a lot of experimentation and placement re fins. I found that out a couple of years ago when I asked a similar question and did research about quad fin placement. I generally try and keep it pretty basic but appreciated your idea.
Kickten - yes that McTavish was a pintail and i based the template on it but made it a rounded square. This guy doesn’t surf heaps but wants to get in the water again.
Rachel - hope it turns out well for you