I've made many changes to Issuma in the nine years that I've owned her. The change that I liked the most was replacing the lifelines with a higher liferail. I'm a tall guy, 188cm/6'2", so my center of gravity is higher than most people's. Taller people need higher lifelines.
Forward of the pilothouse, Issuma is flush-decked, with a lot of camber (curvature) in the deck. With no trunk cabin, when one is forward of the pilothouse, there is little to hold onto except for the liferails.
When I bought Issuma, it had typical yacht lifelines--two wires going through too-short stanchions. Going forward of the pilothouse at sea was scary--all there was to hang onto was the thin lifeline wire, which wasn't far enough off the deck.
Issuma's lifeline stanchions were made of pipe, welded to the steel bulwarks. In Argentina, I had the stanchions sleeved and extended, and then tubing was welded to the top of the stanchions instead of using wire.
A continuous liferail around the boat, welded to every stanchion is vastly stiffer than wire lifelines (it distributes the load among multiple stanchions), and the larger diamter of the liferail's tubing hurts much less when one falls onto it.
People get aboard Issuma by climbing over or under the liferail. I considered, but did not install, a gate (opening section to allow easier access from the dock). The lack of a gate may not be yachty, but it is very functional--the continuous liferail, welded to all stanchions, is stronger, stiffer and simpler than one having a gate would be.
The lower lifeline wire was replaced by 8mm rope, tied with clove hitches or round-turn-and-two-half-hitches to the stanchions. Amidships on either side, there is a section of rope that I untie when at a dock to make it easy for people to climb under the rail (tall people climb over the rail). The rope requires occasional retightening.
I've sailed Issuma about 50,000 miles after replacing the lifelines with the liferail. The liferail makes a great handhold, feels much safer, and takes much of the apprehension out of going forward of the pilothouse at sea. Unlike wire lifelines, which require periodic replacement, a liferail requires no maintenance.
Higher liferails or lifelines result in more chafe on sheets. On Issuma, the mainsheet, jib sheets and spinnaker sheets all rub against the liferail. The smooth surface of the tubing results in very little chafe--the mainsheets have about 100,000 miles on them and are still going strong, the other sheets show no signs of chafe. Chafe would be greater if I was using wire lifelines (thinner diameter, not as smooth as tubing) instead of stanchions.
I got the idea for the liferails from two books, Brent Swain's Origami Metal Boatbuilding, and William G. Van Dorn's classic Oceanography and Seamanship.
I made the mistake of painting the liferail and stanchions. I used two-part epoxy followed by two-part polyurethane, but rails are pretty difficult to avoid scratches, and once the paint gets a scratch, moisture gets in. Moisture freezes, expands, and then lifts large areas of paint. Without frequent repainting, painted rails look awful. I am letting the paint fall off and one day will have nice, unpainted rails with no maintenance.
I increased the height from the original lifelines, so the liferail is 90cm / 35" from the deck. I did a lot of thinking about this, wondering if I was making it too high, as the normal ones are much lower. After sailing extensively with it, I think that higher would be even better, and if I was to do it again, I'd make the liferail at least 1m / 39" from the deck.