As Simon said, that's the boat JP originally designed before the F16 rules. Actually there were 3 major versions, the original Stealth, the Stealth 'R' and the Stealth F16.

From memory, the original had the following characteristics:

- Smallish not square top main (Ullman)
- Small jib (Ullman)
- Spi (Ullman)
- Rudder and daggerboard where identical (in fact 49er rudder foils)
- 2.4m wide
- canoe bows

The 'R' had the following changes, using the exact same platform:

- Huge overlapping jib (Ullman)
- Longer daggerboard

A lot of original Stealth were upgraded to the 'R' version. Mine is one of those: I have two jibs and two sets of rudder foils.

The F16 version was then optimized for the F16 rules with some other changes thrown in for good measures:

- Larger beam (2.50)
- beefier front beam
- Straight bow
- All sails made by Landenberger, and more recently by Grant Piggot.
- F16 compliant main (square top, larger than the 'R')
- F16 compliant jib (smaller than the 'R') with an optional self-tacker
- Longer spi pole
- Anti-pitchpole rudder foils
- Thinner daggerboard
- Different trampoline lacing
- Mast rotation at mast base

A lot of upgrades have been applied to older Stealths, anything from canting the hulls, changing the sails to F16 sails, adding foils, widening beams, you name it...