That's a Z-scarf Dave. The fibreglass laminate is actually scarfed at about 15:1. You don't need to tape over it. ATL guarantee something like 90% strength compared to a continuous piece of Duflex. (I dont know the exact figure) I do know I have break tested some joins on scrap material, and the scarf appears to be just as strong as the rest.
Some nice points about the Z-scarves -
Using ATL's Z-press, you can join panels quickly. (It's a heated press in which the joins cure fast) I joined 160 panels (1.2mx2.4m each) in 3 days. (There's a photo
of a Z-press at work here:
The Z-joins only need a little sanding
to remove excess epoxy
to make them quite fair.
The Z-joins do not produce "hard or soft" points in the continuous panel - when you bend a series of joined panels they bend evenly through their entire length - it makes getting fair curves easy.
Of course the big one is, you don't need to tape over them.