Prototype design concepts from the book “Surfboard Fin Design: Just the Basics” available from Amazon here.
As a friend of mine constantly points out that if the human race were concerned about air pollution and energy over consumption then we would not be driving around in the cars we’re driving around in. “Huh, what do you mean?” most people ask him.
He then goes on to explain about air drag. We drive around in cars with the driver seat next to the passenger seat. This makes the front surface of the car wider and thus displace more air as it moves along. VW came up with this car back back in about 2002.
So what does this do?
Well my car takes about 55 litres of fuel and gets 450km which works out to 8.2km/L. Most sedans do better than this and most 4WD’s do worse, but it’s not much either side.
When you put the passenger directly behind the driver the efficiency goes to around 100km/L. People will justify all sorts of arguments in their heads against this, but the only way to look at it is this:
Take your existing car you drive now with it’s current engine and current mass.
Put all the seats directly behind the driver.
Curve all the forward edges and
if you can, make the wheels narrower.
Your fuel efficiency will improve drastically.
VW is going towards the same shape with the XL1
which is said to have an efficiency of about 68km/L. However the marketing department has had the final say and totally destroyed the key feature of passengers behind the driver.
I understand that if you need to carry big heavy items you need a big vehicle, but most of the time it’s just a couple of people and basic luggage. At 100km/L verses 10km/L I think many of us would start to rationalise just paying a freight company to carry our big items a few times a year. Then again if you want to convey prestige, power, wealth and (in some peoples minds, sexual prowess) then you should definitely stick with a Hummer, Land Cruiser, or F100 with the widest nobbliest tires on the market. Oh, and upgrade the engine to race spec.
Having said all the above, I look at my own doings and realise through my actions that I am not really an environmentalist at all, even though I’d like to think I am.
Due to my frustration with the surf conditions relative to my current boards on the east coast of Australia, I have finally decided to take the matter into my own hands. The old boards I have still work great in Western Australia, but there is no where near the power here that you’d find in Margs. Also since leaving WA and coming here I’ve gained 7-8 kgs or more and that makes a ridiculous difference. Especially when the conditions are marginal. I have been out on so many days with other surfers and watched whilst the 75kg guy gets wave after wave till his legs are burning from cutting back so many times. I only get 2 or 3 waves floating at about the mid 90kg mark (now heaver than that) on a 6’8″ , 2 3/4 thick board and the 105kg guy on a 7’8″ mini mal has no hope in hell of catching anything.
So I’ve grabbed some blanks to shape. Testing tail width first. I’ve surfed a couple of boards around here wafer thin, but with wide tails and they seem to work.. My current board has the 14.5 inch rounded tail at the standard 1ft from the tail. I figure I’m going to throw the first few boards away, so I’ll also try some weird radical ideas whilst testing tail widths. The tail width here is 18″ (457) right to the tail. Going on snowboard theory, I’ve bent the rails in and then in the profile I’ve made them as close to 89 degrees as possible. The rails have rocker lengthwise and I’ve concaved out the underside so the centre is dead flat tail to nose 2/3 of the way up the board. This flat I’ve drawn into a concave tail so that as the air compresses in under the board it can exhaust out the back once planing. The blank was not big enough to do full length snowboard style rails so I had to cut the snowboard rails shorter. Probably next time I’l just make it from a block of EPS and vacuum bag some divinicell on top and go the epoxy route instead of polyester. Standard surf blanks are not really geared to trying weird shapes. I want to incorporate flex so that as the turn is lent into, the board bends with the turn like a snow board, but that can happen on a later board. I think I’ll probably test it without fins first to (a) purely test the planing ability of the 457 tail and (b) if it does get me going see if I can turn on the rails without fins. Either way the fun is in the design process and not so much the surfing.
The deck is also concave as I skated for years and know the difference between the old 80’s flat skate decks compared to the >90’s concave decks. Christ knows why surfboards didn’t follow the trend. I’ve seen a couple, but it’s close enough to none for it to be none in mainstream surfing.
Now that it’s shaped I really can see that I wanted to go 510 (20″) or 535 (21″) in the tail. That was the limitation of this blank, so it’s a starting point.