Hi Duffman,
Sorry I missed this ... I usually click on "Show Unread Posts since last visit" and this one didn't show until now.
The /0 system is confusing. When some people talk about saltwater reel sizes they may talk in terms of 1/0, 2/0, 3/0, 4/0, 6/0, 9/0, 10/0, 12/0, 13/0, 14/0, 15/0, 16/0, 18/0 and 20/0. The /0 on the end of these terms seems to have been made up for a reason which was shortly thereafter forgotten and has remained "shrouded in mystery" for many years. It simply meant "OCEAN" or reels built primarily for saltwater use.
Did all companies make their reels in all these /0 sizes? No, many companies made only smaller reels and many companies made only larger reels. Only a few companies made reels in most sizes.
Were the /0 sizes used as a universal line capacity measurement agreed upon throughout the industry? No, although most companies' reels were quite similar in size it is not uncommon to find companies whose reels of the same /0 size did not have the same dimensions or line capacity. Even within the same companies the /0 size would change over the course of a few years. Not all companies used the /0 system to size their reels.
After much research a few years back, my belief is that the /0 on the "ocean marketed reels" dates back to a time when lines were classified by the number of threads they contained, rather than breaking strength. So, a 6/0 was a "saltwater ocean" reel that held 6 stranded line.
As for today, most reels are labeled according to the size of the line they best handle. For example, 20, 50 and 130. Some labels suggest a range. For example, 50-80. In any case, those labels are easily understood.
Of course, to mess all this up, braid has come along. So, for me, when I am in doubt, I contact my custom rod maker (Kevin or Greg Bogan) and ask them or call the manufacturer. Penn and Shimano have always helped me out. I have other "conventional" reels but they were recommended and the rod was custom made.
As for rods, I made a "tip" a while back that can be found at:
http://njsaltwaterfisherman.com/index.php?option=com_content&task=view&id=133&Itemid=91To summarize it, the general rule for line rating for a rod is:
1. For a 50 class reel, use a rod rated for 30-80 lb. line
2. For a 60 class reel, use a rod rated for 40-100 lb. line
3. For an 80 class reel, use a rod rated for 50-130 lb. line
This is with traditional mono. Again, advanced line materials have clouded this up a bit.
Confused now?
Capt. Ed