I think we need a GPS Team Challange Tandem results section.
So that we can track results and stimulate others to make one.
It would be good to track improvement over the years 
We can gybe and tack the Starboard Gemini, but I cannot imagine gybing the SpeedTandem, it is far too small/narrow for that...
Any chance of getting some specs/dimensions on the board for a one-design speed tandem challenge. I take it that it is a polyester/pu board with a us finbox...
No problem.
You will have to translate into metric, but basic measurements are 10'8" x 20"
I will make some more measurements on Thursday and post them.
It was made on a Polyurethane Burford blank which had its rocker reduced when the single stringer was inserted. I am not sure of Burford still have the moulds for this blank. I was disappointed to find they don't have the 'speed board' moulds any more.
The US fin box (Chinook) is a both an advantage and a disadvantage. The advantage is that the position can be adjusted fore and aft for directional trim, which we have found quite critical. The disadvantage is that we can't easily use the latest available speed fins which are all Tuttle base.
For our 'slalom' tandem we will be building an adjustable 'Tuttle' box so we can trim the fin fore and aft.
like only sail in your own state, Ha ha. finally got internet back after 2 weeks bloody telstra. hope to be speed sailing on sunday, friday looks good as well but robe wave comp is on.
like only sail in your own state, Ha ha. finally got internet back after 2 weeks bloody telstra. hope to be speed sailing on sunday, friday looks good as well but robe wave comp is on.
I had a few spare minutes and did a quick model by scaling your photos Andrew. The blank/block is 160L...
Great skills mate! 
Looks very close to my eye. The tail is a bit rounder and perhaps a tiny bit wider and more parallel in the rails towards the tail, but very, very close. I will post some measurements tomorrow. Can you get measurements off your drawing?
If you work a long Tuttle box, think ,that you need always the ends of the box,
it hold the fin higher or deeper. Wolfgang
Correct Wolfgang. The ends will have standard Tuttle box taper shape and the blocks will fit between the fin and end to wedge the fin tight.
I am amazed at how close Tims figures are. I finally took some careful measurements and will PM them to Tim to adjust the plans.
The actual length is 10' 6 1/2" which is spot on 320cm
The measured width is 20 1/4" which is 51.5cm
Widepoint is further back at 1850
The tail is a little wider as I thought: 50 = 159, 150 = 230, 300 = 289, 500 = 350
The measurements for the center of the footstraps are spot on but we have added and angled strap for the rear sailor using the front hole of the front strap.
Back mast track goes back to 1010mm from tail, and goes 230 forward in 2 steps.
The front riders back strap is also in the back track and goes forward the same amount for upwind sailing
Front track starts at 2140 from tail and goes forward 420mm.
The rocker is not as flat as it looks in the tail.
It is flat to around 90mm and then rolls over over about 100mm to another flat to 150. With the straight edge on the second flat there is 4mm of tail rocker. We used this type of rocker a lot on our smaller speed slalom boards and it works very well, allowing the board to ride on the tail flat but also plane up easy and ride flat in the chop. It certainly works on the Speed Tandem!
With the straight edge hard on the second rocker the total nose lift is only 150mm. Not sure how much if you held it hard on the back flat because my straight edge was not that long. 
