Nick,

How did the Turtle fair? I believe you can fix their shells with epoxy.

With regards to running sheets etc.

On the F18 we ran 1:2 purchase on the tack line which meant we could get the tack to the end of the prod in one tug. On the Tornado I've now been convinced this won't work as we've blown up one cleat and stripped two ropes. But on the F16 it should work. Either way assuming you usually do port rounding courses run the tack line to a small turning block near the dolphin striker to a cleat mounted near the port hull. There have been heaps of photos posted on various trip line systems. At the outboard port edge of the both beams attach a small block (drill a single hole through the beam for a lashing (knot and washer in beam). Thread the tack line between them and then to a third block above the tramp on the centre line. Tie a metal ring to the tack line immediately after this third block. When the kite is in the bag the ring should be hard up against the back beam. This will allow you to pull the tack line out to the end of the prod from anywhere on trapeze, so if you have overshot the mark and are power reaching in you wont have to work fwd to the front beam as required by most people's systems where the tack line goes into the beam.

Run your halyard down through a cleat on the mast (assuming you usually sail two up) to a turning block either on the beam, tramp or base of mast depending on your preference through the ring on the tack line and then though the tramp into the shoot. You'll need to experiment with lengths but typically if you have about 1-2 foot of slop in the halyard when the kite is packed away then you'll have more than enough as the end of the tack line moving fwd will give you a lot more to play with when the kite is hoisted. By doing this you won't need the shock cord most people have in the system.

On 18s and Ts, I've never had an issue with the kite sheets ending up in the water and if this is happening you may find they are too long.