I believe the original AHPC F18, which was a modified Taipan5.7 had canted hulls. This is from the
F18-international.org website
HISTORY
In July 1996 Pieter Saarberg write to Jim Boyer asking him to investigate the possibility of modifying the Taipan 5.7 hulls to suit the F18 formula. His reasoning was that the present designs of the F18 did not offer the quality of workmanship or fairness of hull shape that the Taipan 5.7 did.

The prototype Taipan F18 was shipped the following January. The first season was less than successful, with many teething problems, for the second season Pieter invited Scott Anderson to use the Taipan F18 in the around TEXEL race, the only chance Scott had to tune the boat was the 20 minutes waiting for the start. Scott won. At last the results are on the board.



PLATFORM
Based on the Taipan 5.7 The Taipan F18 is built from all woven and unidirectional fabrics, this gives an exceptionally stiff hull.

Throughout the Taipan F18 we have endeavoured to use the extra weight to advantage, rather than just add ballast to bring the boat up to weight, needing 30 Kg in the platform alone this has been a real challenge. Vinylester and polyester resin are used in the construction. Framing low density foam with fiberglass reinforcing, to enable the Taipan F18 to meet flotation regulations, this type of frame is also better as the frame footprint onto the hull is large reducing local skin loads. Beams are 3mm wall by 100 mm diameter Aluminum, mounting points use brackets to prevent any movement between the hull and beam.

Rudders are standard 5.7 / Tornado, we have increased the weight a little, but not too much as excessive weight makes the foil difficult to handle. The centreboards will be increased by a few Kg, but not to the maximum for the same reason. Their size is 300mm X 25mm X 1100, as I am very doubtful of the benefit of the very long narrow boards seen on some other F18’s, the shorter boards are also far more practical when leaving the beach.

The hull is a modified Taipan 5.7. 100mm trimmed off each end. We are delighted with the resulting hull, it is fair and well balanced with the correct amount of rocker. The Taipan 5.7 was designed to carry up to 340 kg (140Kg Boat & 180Kg Crew), so the modification to the F18 is an ideal shape to carry the 180kg boat weight and 140 kg crew. The bow is taper cut so that the bow remains fine. I know from past experience with the A-Class, and Taipans that it is better to keep the bow fine rather than trying to increase buoyancy in the bow, as the boat will tend to "trip over" a more buoyant, wider, bow.

The Hulls incorporate our usual nice touches such as built in chain plates, and internal trampoline tracks, which we pioneered.



RIG
Using his Taipan and Tornado experience Sailmaker Greg Goodall started with a clean slate and designed the rig from scratch. He chose the same "wing 158mm x 74mm" section as the Taipan 5.7, and added a radial cut main and jib . For the Spinnaker Greg and Pieter Saarberg Decided that Experience counts and chose one from a Dutch loft that had a reputation for making fast spinnakers for catamarans.