If you boat with pets or small children, netting laced to the lifelines is a very effective way of ensuring that they stay aboard. Strong nylon netting of appropriate width is available just for this use. Lace the netting to the top lifeline with a spiral wrap of nylon cord, or simply thread the lifeline through the weave.
The simplest way to secure the bottom of the netting is to add a third lifeline at or just above deck level. This can be a small wire cable or braided rope. Attach it to existing bails on the stanchion bases or to eye straps fastened to the deck. Feed this bottom line through the netting or lace the netting to it, as you prefer.
For sailors simply wanting to keep doused headsails from spilling over the side, safety netting may be more enclosure than is necessary. A bow net made of criss-crossed lacing will be equally effective but less obtrusive, and it will add less windage. Here again, you can attach the lower edge of the “net” to a third lifeline stretched taut between the pulpit socket and the first stanchion base.
An alternative attachment method, the one I favor, is to fasten a series of small stainless steel eye straps to the deck directly below the lifelines, positioned on 12″ centers. These stabilize the pattern of the lacing, but they do result in additional holes in the deck. To prevent water intrusion, be sure to encircle each fastener with a bead of polysulfide sealant before you install it.
Starting at the base of the pulpit, lace 1/8″ braided nylon cord over the lower lifeline and through each strap eye, throwing a half hitch into the cord every time it passes over the lifeline. If you are using a third lifeline, attach the cord to this line with a rolling hitch each time it passes under. Rolling hitches will keep the cord from sliding and help maintain a uniform weave. After the lower lacing is in place and tied off, lace a second cord through the lower lacing and over the upper lifeline, putting in half hitches on the upper lifeline. Tie off the end of the upper lacing with a rolling hitch, then whip the end to the lifeline.
For more enhancements for your boat, consult 100 Fast & Easy Boat Improvements by Don Casey.