It's an older thread, but perhaps many are still wanting to try Sport.
I mostly sail solo, on 2 man boats, the Hobie 18, Nacra 5.7 & Nacra 5.0. We go with the harness all the time.
Regarding harness, I strongly suggest trying before buying. Our shops here will let you "hang" on dry land, for as long as you want to try them out. Something that feels OK when trying on, may feel entirely different when holding your weight, especially after an hour or two.
Harnesses are a very individual thing, what Sailor A swears by may be very uncomfortable for Sailor B. Any of the higher end products, like Zhik, or Gul, (I have both), are worlds better than the diaper,(nappy?) that the early Hobie sailors used. If we go 60km down the lake, the diaper gets uncomfortable quickly. You need the built in back support for longer stints.
I would not worry about adjusting length while on the water. You already have two "heights" built in. You can engage the bottom of the dogbone, or the top ring, giving two different lengths. If you do elect to use the adjustable line, be sure to have a knot at the appropriate height to prevent a runaway if your grip, or the line slips. That is a guaranteed swim.
You also need an adjustable tiller extension. We use the Arriba Hot Stik. For the the 8' wide Cats, a 96" Stik works. Trapping off the wings of the H18, or the wings of the 10' beam Mystere required a 10' Stik. I think the Arriba is pretty heavy duty for the Dart 15,(and maybe not legal for the racers?), mine came with a lightweight aluminum black anodized stick. It works the same as the Arriba, twist to unlock, pull to desired length & twist the other way to lock. You need it extended while on the wire, but if the wind drops you want to be able to shorten it if just sitting on the hull. These can be adjusted on the fly, even in wild conditions.
To be most efficient, you want your body horizontal, like a plank, however this is often not desirable, depending on the state of the seas. In large waves, it is often better to be at only a 45* angle, to prevent being washed off the boat by boarding waves. As you all know, waves at speed have considerable force. It is also gives much more confidence to those just starting out.
If you regularly sail in higher winds, being on the wire is a far warmer, drier ride. We rig all our larger Cats with double traps, that is a thrill, if you can find willing "rail meat", with both of you on the wire. An even bigger thrill is being trapped out off the Wings of an H18 or Mystere, you are a long way up when that hull lifts.
Now the downsides. In addition to the extra rigging, there is some danger, both to the boat & sailors. When flipped, most people belly up onto the hull. One must use care, & be aware of the "hook" on your harness. It is very easy to drive the hook through the side of the hull, especially the thinner skinned boats.
Another danger, small, but none the less present is flipping the boat, especially turtle, & getting caught up in rigging, either under the tramp or on the mast. Rare, but there have been fatalities. Many of the races DownUnder require a quick release harness such as the Bethwaite(sp?). There are a coup0le of different quick release designs, either a ball that be pushed out, a large velcro strap that when pulled releases the hook, or a big red button that you push, like a seat belt release in a car. I use the latter, but I don't think it is any better than the former two. Many sailors also carry a knife with a fixed blade, in case they get caught under the tramp. Obviously it has to be readily available to use with one hand.
Trapping is not only for the younger members, I am turning 60 & use a harness almost every day, the N5.7 will fly a hull in 10kts wind, the 20' x 10' Mystere will lift up in 7kts. Being on the wire allows you to use more power, & leave the others in your wake.
