I guess it's really dirt-sailing/surfing [1/20/05; Actually, it's called "Speedsailing" -- and it is very popular in coastal Europe (UK, Belgium, France). Search for "speedsail" on Google and see what I mean]. The guys that surf/skateboard down mountainsides without a sail rig are "dirtsurfin." But anyway, it's a hoot and it sure beats loading the car with all the windgear and driving for 90 minutes (to Tybee Island or Clark-Hill/Strom Thurmond Lake) only to get skunked. I can get to the surfin site (any open field) AND get rigged in minutes. What fun!
 "The Dog" Padre Island, Tx |
This page provides some info on how the kids and I got involved. Short story- I was looking for windsurfing trailer designs on the web and saw a photo of a dirtsurfing rig and started looking for a board. Experimentation has gotten us this far. I love it because using a dirtsurfer makes it so much easier to teach the kids the basics of windsurfing.
M E N U
Equipment & Environment
Board | Sail/Rig | Sailing GroundsVideos
Sail Control | Board Control | Beach Start | Carving | Broad Reach | Tack | 360° | Jibe | Dismount | "Dirt" Start
Laydown Jibe | Tandem Riding | WipeOuts | More to come...
Outback "Indo Triple Trax" Mountainboard
48" | 22 lbs. | 12.5" wheelsI first found an inexpensive starter board. $110 (incl. shipping!) got me an Outback "Indo Triple Trax" Mountainboard. I found mine on ElectroMavin's website (they no longer have these). The Indo Triple Trax board was originally designed for snowboarders who wanted to snowboard where there is no snow. John Milne of Australia came up this this three-wheeled design which includes a "stomp" brake (uuuh- rather, decelerator) at the rear of the board. The board is about 48" long and has three 12.5" wheels. You can install footstraps if desired (2 are included in the purchase). I'm using one on the rear of the board [10/4/05; not any longer, they seriously hamper footwork during jibes]. The Indo board is designed for lightweights. I weight 140-- (the kids go down to 75 lbs. [120, 100, 75]) so it suits us fine for now. We now have three of these boards and I often ride tandem with my youngest (140 pounds + 75 pounds = 215!). These boards ride like a dream but you must keep your weight on the back half of the board or you will spinout or worse nosedive (and catapult). This board does not work well in loose sand. The single rear wheel provides little lateral resistance once the sail is loaded.
Outback "Fury" Mountainboard
42" | 12 lbs. | 8.5" wheelsThere are many other mountainboard models available- some rated for up to 250 pounds. Our fourth board is an Outback "Fury" which is a four wheeler- and very popular with kiters. It has 8.5 inch wheels- is about the same length as the Indo but much lighter. I am surprised that the Fury is MUCH LESS manuverable than the Indo. The turning radius during jibes is at least twice as large. Also the Fury can be "InFurriating" to use. Board control is a MAJOR hassle compared to the Indo. The Fury cannot be spun into position- but then it doesn't spin out during powered up reaches either. (This board's for sale- Let me know if you're interested.)
Most sailing dirtsurfers prefer a four-wheeled configuration- but of these two boards I far prefer the 3 wheeled Indo.
I did have to modify the "Triple Trax" board. Initially I mounted my mast base/foot on the very front of the existing deck (like "The Dog's" photo) but I could NOT generate any power unless I was running within 15 degrees of absolutely downwind. I did a little research and discovered (Big THANKS to Paul Miller, Assistant Sailing Coach at the Naval Academy!) something called a sail's "Center of Effort" (CE). To determine a sail's CE you draw a line from the midpoint of the luff, leech and foot to the opposite corner. Where the lines intersect you'll find the location of the sail's CE.
The CE must be positioned in front of the center of lateral resistance (CLR). The CLR on this board is the midpoint between the front & rear wheels. The farther the CE is from the CLR the greater the rotational force exerted on the object. I found that if the mast base was positioned any farther than 6-8" in front of the board I would violently "spinout" in moderate (10-12mph) winds. A couple of inches made a LOT of difference too! I've found that in a broad reach if I "sheet in" too much I actually reduce speed because I INCREASE lateral resistance by moving the CE deeper into the lateral resistance zone. See my illustrations on this if you are interested in this effect.
I find that on a broad reach the optimal position of the sail is sheeted out about 40-45 degrees. On beachstarts if you sheet in beyond this angle the wheels of the board generate too much lateral resistance to get underway.
At present our boards use this deck extension design: bottom view | side view
Other board designs:
My Suggestions to Outback: Frame Extension | Deck Modification
DirtTheory Crossbow Mountainboards
Notuna Boards - Australia
TerraBoardTwo words - "OLD STUFF!" Your boom and sail must endure a lot more abuse in this environment. Your gear will get dirty. Dropping your rig as you cruise across a sidewalk will drastically reduce the value of your gear. My boom and sail combined are probably going to go for as much as $5 at the next swap meet.
So-- don't use your good stuff. Otherwise rig just like you would for the water except if you're on grass- rig bigger- maybe a meter & a half up. I've found that my 7.0 Retro (largest sail in my quiver) is "barely useable" in 10MPH breezes- good at 15... Awesome at 20+. About 16MPH is required for a "dirtstart." These figures are based on my personal experiences (140 pounds/7.0 sail).
Okay- my new dirtsurfing friends need this info--
What pieces are included in a "sail/rig?" The "rig" includes the sail and is basically everyting you need excluding the board. The rig is composed of these parts (working from the bottom up):
- mast base/foot; connects board to sailing rig (mast, boom, sail)
- mast extension; slips into the bottom of the mast and can be extended for larger sails.
- mast; fiberglass/carbon spar that extends the "luff" eading edge of the sail.
- sail; made of dacron & mylar (clear material). Most are designed with battens to stiffen the sail.
- boom; extends the clew (aft-most corner of sail) away from the mast. Windsurfing booms use a "wishbone" design, providing a handhold on either side of the sailing rig. The boom connects to the mast via clamp built into the boom.
Watch a rigging movie to hear about each piece.
The rig comments above refer to rigging for FLAT grassy terrain. We sail on the Recreational Activity Center (RAC) intramural fields here at Georgia Southern University, in Statesboro, Georgia. It's mostly flat, grassy and open. We have about a 350 yard fetch in most directions.
There are plenty of obstructions to make sailing here interesting... a few sets of bleachers, soccer goals, portable softball fences, light posts, a sidewalk bisecting the area, and a surrounding chainlink fence. I don't have the nerve to sail on asphalt. My gear is expendable-- but my body parts are not. So we are sailing on grass. I've created a still panorama and a VR movie of the area.
Understand that you can potentially sail in a multitude of places. Your rig can go UPHILL with the right gear/conditions. I've seen videos/photos of guys sailing uphill on ski slopes(!) and others launching off dirt mounds to simulate wave sailing. In any case going upwind (close hauled/beating) is difficult unless you are pretty powered up- so rig big or plan to walk some once you are on the property line.
A note on dress: You are going to get dirty. Dress for it. If you don't know how to fall gracefully (sideward barrel rolls with arms and knees bend and head tucked forward) wear safety gear including, helment, gloves, and knee & elbow pads. Serious dirtsurfers wear body armor- Really! Shorts and vests with padding sewn in! I personally favor shorts or jeans, and socks and good pliable running shoes. Be careful if the sailing grounds are wet. Muddy soled shoes slide off the mountainboard decks.
V I D E O S
Sail Control
The sail is never in the proper position for simply hopping aboard. So you must master controlling your "rig" (mast, sail, boom assembly). This includes walking the rig into position on the proper upwind side of the board, "flipping" the sail across the windline, and popping (or snaping) the sail into it's proper shape so that maximum lift is provided. Practice this ALOT before attempting to sail.Board Control
The board- it would seem, is also not inclined to co-opperate with the dirtsailor... and you don't want to drop the rig to adjust the board. So you must learn to manipulate/turn your board using the rig to apply turning pressure to the nose of the board.Beach (Standing) Start
The usual mount in dirtsailing:
1. Position Sail, 2. Lift rig, 3. Align Board, 4. Prepare to Mount, 5. Sheet in/Mount up, 6. Sail awayVideo- Position your board perpendicular to the wind. Lift your rig by the mast and walk (mast leading) toward the wind. Once your mast is perpendicular to the wind lift your rig (grasping the mast and the lowest side of the boom) to swing it above the mast base. Allow the trailing edge of your sail to luff or flag in the breeze. If you need to flip the sail to the opposite side walk through the wind line and allow the sail to flip to the other side. Make sure your board is still perpendicular to the wind (your flagging sail and the board should form a right angle). If it is not, turn the board using your rig and/or your feet.
Tip your mast toward the rear of the board while grasping the boom with the rear most hand. Maintain control of the mast with the front hand positioned on the mast above the boom. Place your rear foot on the rear of the board. While keeping your weight back, lift the mast and sheet in while swinging the front foot onto the board. Keep your body primarily extended. Do NOT bend at the waist. And don't fight the sail. Your arms are slightly bent and your shoulders relaxed. Use your body weight - not your arm strength) to control the sail. Keep the mast upright and balanced so that it supports itself. If you feel like you will get blown over the board sheet out a bit and trying "sitting" more - bend your knees and hips to resist the sail's power. Use your feet to control the turning direction of the board. Dig in your heels to turn upwind. Shift your weight toward your toes to turn downwind.
Broad Reach
Here's Samuel (age 16) on a broad reach (it was blowing about 8 mph) and his first jibe attempt. Here's another reach coming back. Samuel's on the old 5.8 dacron sail.Carving
It's a kick to carve mini S-turns as you cruise along. It requires nothing more than shifting weight between the toes and the heels. The board's front truck will turn the wheels in the direction you shift weight towards. If your board feels unstable and constantly wobbles side to side you'll need to increase the spring shock tension on your board. Get comfortable shifting your weight to both port and starboard. This will be critical in learning downwind turns called jibes. If the winds are low you can incerase power by "pumping" as I am in this videoclip.Tack
The only tacking I've been able to do is a "walkaroundontheground" tack. But I have seen guys do this on speedsailing boards.360°
Found this clip on the web. I think the guy is from Germany. A cool manuver - starts as a jibe, but the turn is maintained while leaning the sail windward to prevent sail loading.Jibe
What a hoot! Wind/dirtsurfing is REALLY fun once you start getting the hang of jibing (downwind turns). There are several types of jibes; simple, clew-first, laydown, and duck to name a few. I'm just getting decent a the simple and clew-first versions.
- Simple Jibes 1 | 2 | 3 (movie links):
The images in the sequence below are stop frames from critical moments in the second (#2) 11 second video. This jibe is a port (left) simple jibe.
1. Pick up speed on a broad reach. Shift your weight towards the toes to begin a downwind turn. 2. As the pressure against your rig lessens, shift your front boom hand (right hand in image above) so that it is closer to the mast (about 6" from the mast). At this point, Push the mast windward and reverse the position of your feet by moving your front foot (my right is forward in the image here, Remember, FRONT FIRST!) behind your rear foot. Then pivot on the "new rear foot" to complete the body turn. This happens very quickly- and it is important to keep the board turning as you pivot. The hands maintain their position on the boom during the pivot. Note that the rig is upright and balanced throughout. 3. Your new stance achieved, shift your weight hard to the down-wind side of the board while tipping the mast towards the wind. Be ready! This will greatly accelerate your turn. You'll be standing upright (but weight shifted backward toward the wind) momentarily as the board turns through the windline. 4. By now, the sail is begining to load (capturing wind force) and your clew (rear corner of the sail at the back of the boom) is pointing towards the front of the board. 5. Release the hand closest to the clew (left here) and your rig will rapidly swing downwind. Continue to keep your weight to windward so the board continues to turn across the windline while... 6. reaching across the top of your other (right) arm to grasp the boom with the "new front hand." Immediately release the old front boom hand to regrasp in the new rear hand position. Push the mast forward above the base and... 7. hang on! As the sail loads shift your weight back/windward as you complete the turn and sail away on the opposite reach. - Clew-First Jibe: The clew-first jibe is the same as a simple jibe- you just hang onto the rig longer after pivoting your stance. Make SURE you push the mast upright as you flip the sail!
- Stringing Jibes: This set done on 8-10 mph day on my 7.0 Sailworks Retro.
Dismount
Getting off your ride without tumbling cxan be a challenge at first. To dismount, dig in your heels (shift weight to windward side/edge of board) to turn the board upwind (point the nose of your board into the wind). Step off your board with the front foot to windward while holding the mast overhead and sheeting out."Dirt" Start
The "Dirt Start" is executed much like the windsurfing waterstart- only no swimming the sail and/or dragging the boom over the back of the board required.Point your board slightly downwind. Position the sail so that it covers the rear of the board with the mast edge (luff) is nearest the wind. Sit down under the sail and place your rear foor on the back of the board. Place your front foot on the middle of the board. Slide your hips forward towards the board - knees and hips are bent. Hold the rig up with the boom and wait for a strong steady breeze. Push or pull on the mast base to rotate the board as needed- (a kick on to the front wheel sometime helps!). As the wind arrives, push the rig upward (and mast forward) and HANG (like a sack of potatoes- do NOT hike out! or execute a chin-up!) on the boom while sheeting in. Keep pressing with the toes so that the board moves on a slightly downwind reach. Gradually the rig will pull you into a semi-squat atop the board. Slowly stand- and sail away. If you do a chin-up, hike-out, or shift your weight to the heels you are likely to turn windward and lose all power. Of course, the dirt sailor doesn't "need" this skill, but it is a great way to simulate/practice a water start.
Laydown Jibe
Duck Jibe
Tandem Riding
WipeOuts
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