Next Project: A bi-directional surfboard for kitesurfing

General Discussion
1

Hi all,

I’m working on a new design that is still in the “thinking” stage of development. I’ve been pondering this design for a couple years, but recently a couple companies have released production boards that are similar to what I’d like to create.

The concept - Basically, I’d like to create a surfboard for kitesurfing that will perform like a surfboard in one direction, but I can also ride backwards (on the nose of the board) so I don’t have to do the “switch-stance dance” to turn it around. Although I’m a veteran surfer and kitesurfer, I’m just too much of a klutz to switch stance (or maybe just too lazy to learn). I’ll probably be riding this in fairly small waves (no bigger than hand-high sets) in the Great Lakes and the East Coast’s OBX (I’m moving there later this year).

The design - A couple companies are now making production boards that follow my general idea, but unfortunately are way too small for me. I’m 6’5" tall and weigh 240 lbs (110 kg) and the production boards are typically designed for guys who weigh 165 lbs ( 75 kg ). Attached are two examples of boards that are similar in concept to what I’d like to build. Both these boards are about 5’ (155 cm) in length, so by simple extrapolation I’m guessing my board should be about 6’6" or longer. I’d like to give the surf side a swallow tail (just cause I think they’re pretty), flat rockered (so it will ride fast while kite-powered) and fairly wide (or almost “fish” - like). I’m thinking I’ll use small, quad-fins for the surf side tail and either one or two fins for the kite side tail (nose).

Construction - since this board will be an experiment and I’ll be moving to an area where normal board building supplies will be hard to find, I plan on using a building technique similar to what I saw in the “Home Depot” and “$14 Blank” threads. My last 3 boards were all built with Divinycel and WEST epoxy, so I’ll probably try to build this one using Home Depot EPS foam, WEST epoxy and a fairly heavy layup. I’ve got a good vacuum pump that I can use and may even try to use wood veneers or door skin if it doesn’t make the board too much heavier.

Any and all comments, suggestions are welcome!

2

Kahuna,

If you don’t plan on having this board as a “dual purpose” board (for kiteboarding and paddle surfing), then I’d suggest that you don’t need the volume. Volume doesn’t do much for a kiteboard, other than make it squirrely when the chop picks up. I know lots of the wave guys are using scaled down surfboards; that said, alot of guys are using boards that look alot like towboards; thin, low rockered…just divinycell or corecelled boards; no eps or PU core. Much better for impact resistance (BIG impact that is); PU or EPS cored boards and jumping is a big NO NO (where’s the fun in that?). A thinner construction would allow you to have a board that will withstand flex cycles a bit better such that you can have a flatter rocker in the “static” sense, but will flex a bit to allow you to really crank a turn. Thinner will also give the rails much more bite for ripping upwind. Keep’em pretty sharp; chine them for rail profile with good water release.

In my experience, when kiting, going much over 6’ in length really increases the beating you take in the chop. I’m not your dims, but I ain’t small either (6’2", ~ 200lb). Width, on the other hand, greatly increases the low end potential of a board (earlier planing). All that the volume will do for you is give you a bit more float, and yes, a bit more glide in the lulls if you’re underpowered, but you can get some of that glide with a flatter rocker and a wider board. Widest I’ve gone on my kiteboards is around 19". Any more than that, and even with my size 12 feet, I think I’d have a tough time railing it over hard enough to drive upwind.

One fin in the nose will probably be enough. Have a look at the OR Mako; people love that board. Granted, it gets it’s “grip” through the ultra-deep concave, but if you’re just looking to get “back out”, shouldn’t be a problem. Again; usually you’re stomping on your back foot pretty damn hard when you’re kiting on a given tack, so the “nose” on any given tack is pretty far out of the water such that you don’t really have to worry too much about the nose pearling or fin catching. I just wouldn’t pu a “huge” fin on the nose. Long for drive and grip; just not deep.

As far as where you’ll be going…plenty shipyards around the great lakes and on the east coast. Board building supplies won’t be any harder to come by, other than the fact that you may have to mail order stuff. If you haven’t made the switch to Resin Research from West, then you should…infinitely better resin, substantially safer as far as exposure is concerned. You WILL be able to get corecell and d-cell in that area. The REALLY big benefit to using this stuff (other than impact resistance) is that they’re both closed cell, so if you’re unhappy with your fin locations, you can just drill a new hole, seal it with epoxy, re-drill it and reposition your fins to your liking. If you go with an EPS core, you will DEFINITELY have to reinforce the fin inserts or they’ll rip right through your board with the forces involved in kiting and water intrusion will be a problem.

RRD Toxic wave…interesting board, for sure…but it IS short and the design WORKS at that length. Have a look at Stretch’s “Trow”. All of these baords are evolutions of the “mutant” design…Personally, don’t think they’re spawned of “surfboards”; more like directional kiteboards that have improved low-end over the older mutants that were designed for top speed and big, hooked in jumps.

HTH,

G

3

Great feedback G, thanks! Couple comments and a bit more background:

I understand where you’re coming from and what you’re saying. I started kitesurfing on a 7’6" surfboard (by George Viciente here on Oahu) 7 years ago and progressed to a number of “twin tips”, mostly of my own design, over the years since. My current board is 155cm x 45cm x 3/4" thick and about 1.75" rocker and I fly Peter Lynn kites (notorious for poor bottom end performance but super reliable in the waves). The board is perfect for me in most conditions except when I want to really “surf” a wave. I tried deeper fins (Jimmy Lewis makes some very nice 2.5" “surf” fins) which helped but what I find I really need is a narrower tail, more fin (to keep me from sliding sideways down a face) and more floatation (if I over run the kite and loose power). Width helps a lot, I will agree, but I really feel I need more floatation so I can continue to ride a wave while the kite catches up.

I think what most kiters forget about is just how much heavier 40 lbs (or more) really is. I’m nearly 25% heavier than you, that’s like having an 8 year old strapped to your back while kiting. I’m flying an 19 meter kite while most guys a lit on a 12. I know a 6’6" sounds pretty big, but for a guy my size I don’t think it’ll be a problem. A couple years ago I had a 6’ board (the “Gorge Animal”, which some NW kiters might remember) which looked like a monster to most kiters, but worked very well for me. My biggest issues with it was that it was too heavy and had too much rocker, but otherwise worked pretty well.

I have the great fortune of kiting at the same break as some of the best wave riding kiters on the planet (including Reo Stevens and Felix Pivec) and have spent hours studying their style. What most kitesurfers do on a wave IMHO is to power up and down a face on a twin-tip. That’s not what I want to do. Nothing gives me greater pleasure than the drop and hard bottom turn on a big face, which IMHO can only happen when I’m actually riding the wave with very little assistance from the kite. I’m hoping this board will allow me to accomplish this, and then when I finish riding the wave be able to dig in the nose and get back out to catch another. A bunch of “sub 200 pound” guys ride Trows or similar here (John Amundsen also frequents this spot) but I have to be way to powered for that board.

This board also won’t be a “dual purpose” board. The days of me paddling a board less than 9’ long are pretty much over. That’s one of the things I love about kiting, I can ride shortboards and feel like I’m in my 20’s again! :wink:

As far as durability is concerned, I don’t jump much so that issue isn’t a big concern for me. No doubt kiting adds more loads to a board than just surfing, so I guess Home Depot and EPS are out of the question. I have’t tried Resin Research yet. What I liked about WEST is that it’s pretty dummy proof. I usually get the gallon cans and mixing pumps which makes mix a batch pretty hard to screw up. I’ve tried other epoxies, but always had problems with a batch that either didn’t go off properly or when off too soon.

I also prefer to vacuum bag whenever I can. I picked up a great little vacuum pump from an air conditioning repair shop for $20 and it’s served me well.

Any thoughts on quad fins vs. thrusters on the surf side? I’m a bit concerned about the extra weight, but due to the nature of how the boards are ridden wonder if thrusters actually work as well?

4

Big K - sounds like a fun project. I only have one kiteboard and not nearly the experience of you or GWN, but I did make it myself after a lot of study. (GWN provided more guidance than anyone else, anyway). I’m right in between you guys - a little over 6’2 and around 222 lb right now. (Summer wt is more like 215 :slight_smile: )

My twin-tip (based on a Hein design) is 159 x 39 x about 3/4" thick and I had to keep adding layers to get it stiff enough for me. As a board 4 cm longer but 6 cm narrower than yours, its probably compatible. My feet are 13’s…

Its a composite.

Top: Double 4 oz - 1/16" balsa - 4 oz biaxial (crowfoot)

Core: 1/2" divinycell

Bottom: 4 oz biaxial - 1/16" balsa - double 4 oz.

All epoxy.

I do, however, have a lot of experience with EPS. Been building lots of composite surfboards for a few years now - and that $14 blank was mine. I agree that its going to be problematic for you to strengthen EPS adequately for kiting - especially for your size - jumps or not. If its really what you’re after, you might want to go with a sandwich core as well as skins - like 3/4" of EPS with 1/8" d-cell on the bottom & 1/4" d-cell on the top & glass in between those layers. Then add the sandwich skins of your choice - either additional layers of 1/8" d-cell or 1/8 or 1/16" balsa or even woven bamboo or wood veneer or something thinner & stiffer. That would give enough top & bottom support for fins & other inserts.

It’ll gain a little weight, but so much more weight is in the rider than in the board, that bouyancy of the board itself will have very little to do with maintaining the glide you’re looking for as your kite catches up - that will have much more to do with surface area & stiffness than board weight. Your dimensions sound good to me :slight_smile:

I also went with a double concave on mine instead of the traditional single to help with the width - puts each concave closer to the rails than it would be if it went right down the middle. With thicker, softer rails for upwind edging, getting that concave reasonably close for transitions seemed important. I tend to think that your board would also benefit from a double concave - running through a thruster setup in the ‘tail’ and a single (or a thruster with little half-moon shaped fins so you can’t catch a corner when they’re in reverse) on the ‘nose’.

5

Thanks Benny1,

First kite board I made (maybe 5 years ago) was a composite 172 x 39 made with doorskins top and bottom and 2 x 1/4" d-cell core and 2 oz to cover. I gave that board what they called a “progressive rocker” which was really a “parabolic” curved rocker. The sucker was very fast but very stiff and a little heavy. No channels, but cut through chop like a knife. For your weight and for flat water / chop, I’d try to go wider for your next board. I’m a size 13 too and I find 45cm wide to be a “magic” number for board width. Likewise, I found boards narrower than 39cm or shorter than 140cm to be too much work. Not trying to brag, but my 155x45 is the best big guy board I’ve ever ridden for flat stuff. Those numbers just sort of work for me.

Not sure what to do about toe-ing in the back fins or no. I’ve read the debates and both options seem to have merit.

I’m also still on the fence regarding thrusters vs. quads. I’ve never surfed a quad, but over the years have owned twin tips, thrusters, 2+1 and single fins. My current surfboard is a floaty 9’6" with 2+1 which tracks like it’s on rails. I borrowed a buddy’s wide 9’2" with thrusters and loved the looser feel the board had. I usually ride more towards the middle of the board for slower carves, so maybe a thruster might be better for me. Dunno…

I’m guessing I’ll use FCS for the back fins and then wake style mounts (3 holes) for the nose. I’ve got a bunch of wake fins, so I probably will try the smallest ones first.

I want to keep the construction as simple as possible so I can design and build the puppy pretty quick. Last couple of boards I designed in a 2D CAD app, but will probably give one of the 3D apps a try for this project.

6

First off . I don’t think that any By dirrectional board works good in the surf unless you are powered to the max, and us big guys can not carry that power. If you drop down a face your front fins catch and your screwed. I really can not use a by dirrectional board because I have a foot injury that dose not allow me to edge a board. And floatation makes a lot of difference for a big guy when you are in the waves. Width in the back of the board is good for guys with big feet and 240 lb. You do not need a lot of width in the nose for a dirrectional board. I find that concaves are not good on a dirrectional board. Flat or V in the tail works best for me . If the board has a lot of volume and width it needs more weight so it dose not pound in the chop and that weight gives more glide on the waves. (tow in boards are heavy for a reason.) The kind of kiting you are describing is more like surfing than Kiteboarding and that is my interest. Every board on the market is desighned for small guys nothing for 200lb. let alone 240. It would be good if you took the time to learn that switch foot shuffle, If you place your straps like a windsurfer there are only two moves to the switch. I like the picture you have of the first board (red) its a good starting point. I would make it a little wider in the back and a little narrower in the front. As far as lenth you could go under 6 feed if you have enough width in the back. My wood fish has turned out to be a big step forward for me . It is 5 ft 10 inches With V in the bottom. It really goes on the waves and turns like !!! Stiff or loose depends on what fins I use. I still don’t have enough imput for me next board but expect it will be about 5 ft 6in. same width in the tail and a little narrower in the nose. I don’t listen much to what the by dirrectional board guys say because we are talking about two completly different kinds of kite surfing. Again flotation dose make a lot of difference as does width in the tail. Aloha Wood_Ogre PS I used to ride Mutants and in retrospect they really sucked!!!