Hi Dan... I'll see if I can help.
OPEN NETS:
My "nylon" nets supplier, I think, was: Blue Mountain Nets, out of Al.
Blue Mountain Industries in Anniston, AL 36201 - Chamber of Commerce
It was VERY high quality stuff, really cheep, (well under $100), and perfect for the front nets shown on Delphys. They WOULD catch us, but we don't walk in them.
I DID ocasionally walk on the nets strung on my previous
boat (already shown), but it REALLY sagged when I did, so I usually walked the beams.
COLOR:
I would stick with black (vinyl coated) nets, because of the chafe protection and the UV barrier it provides. If you REALLY wanted it white, you could buy black dipped netting, and
paint white dip over it. (5X) Sunrise nets sells black dip (and white dip I believe), by the quart. You can
paint dip on the netting with a thick nap roller, and do your border with throw away
brushes. It is
water based...
If the net is all white dipped from the get go, without black under it, then it is just a partial UV barrier. The sun shines right through white or any other very light colored paint, primer, dip, or fabric! (like sail covers)...
All white uncoated nylon nets might last 5 years, and black vinyl dipped nets, that are refurbished every 5 years, might last 30!
The nets we have, as with similar nets made of large square / large cord open nylon... CAN be walked on, if the attachments are strong enough. Thing is, your foot may sink in 12" with each step! It is very clumsy walking indeed. They are fine to catch you if you fall, but not to walk on. Perhaps if the net was polyester and strung under hundreds of pounds of tension, using mounts that are no further than 6" apart? I'm sure it could be done, but it might not turn out to well on the first attempt. Even then, I would expect around 8" of sag with each step.
For really comfortable walking, professionally made, bordered "Polyester" mesh tramps, (like from Sunrise Nets), are the cat's meow! Your feet only sink in about 1.5" with each step, so the tramps are really easy to walk on. We DO have them strung REALLY REALLY tight, with frequent independent mounts. These two tramp/nets for our vent holes, were $1,500 from Sunrise, 18 years ago... So, like I said, they're EXPENSIVE!
You could, of coarse, buy the materials and make your own mesh tramps, if you have a
SailRite sewing machine, but what you get from them is worth the
money. Their borders are 1/4" thick with multiple reinforcing layers, and VERY rugged. We expect to get 10 more years from ours, with re-coats on 5 year intervals.
If
money is short, you can just make your nets of polyester, (Sunrise may have what you need), and make a
rope border as previously described, out of
New England Rope's "polyester" 3 strand. Then, string it as tightly as you can buy hand, with a 3 turn trucker's hitch on each lashing. A drop of
epoxy on each
knot makes it fail safe!
If it turns out right, walk on it at will, but carefully!
SIDE PLANKS:
The lightest thing would be glassed over Kledgacell or Divinicell foam
core planks, about 1.5" thick. You would want to glass it well with biaxial or unidirectional
fiberglass, especially on the bottom. Then use bias cut
fabric tapes on the well radiused sides and ends.
Just like with
wood, any holes drilled have to be drilled large and WELL epoxy coated, like 4x on day one, then sand inside with rolled sandpaper or a chain saw file, and 4X more on day two. If you prefer the "drill WAY large and fill the holes with bog" method, followed by re-drilling... Then do this process before glassing the plank, so that the large bog filled area is under the glass.
If this is too high tech for you, you could just make your plank out of two layers of 3/4" red cedar, re-trim the ends and edges, radius it, and glass it. If it is too springy, it would be good to use biaxial or even a strip of unidirectional carbon fiber on the bottom, (under the glass). This would be heavier than foam, but way lighter than a pressure treated plank. Paint and non skid the top!
Dan, your cheek block re-build looks great, just be sure to glass it carefully, OR at least put on 3 or 4 coats of epoxy and sand it fair, THREE TIMES! After 10 years, the things that develop splits, will always be the unglassed
parts with an insufficient epoxy coating on them. Then, when you paint them, use an opaque grey primer underneath, no matter what paint system you prefer.
Once it has cured and beyond its chemical window... NOTHING STICKS TO UNSANDED EPOXY, not even more epoxy. There must be NO spots left still shiny before re-coating, with anything.
Hope this helps...
Mark