nm on the PM. Found it already in an old email. Obviously there are some irrelevant references to somebody else's oars. Sorry for the length- (short version is sand and refinish):
Without looking at the black oars, I would say that they are serviceable. Obviously if any are cracked or otherwise deeply gouged, that's another story. Refinishing them can be pretty straightforward, but can take some time. Here's how I've done it in the past:
1. Strip off all existing finish. If you screw 2 small blocks into a bench about 2" apart at each end of a bench it helps hold the oar from rolling on you much. You can get lots of the old stuff off by scraping some, with say, the side of a putty knife, but I would avoid scraping hard. Do this part gently so you don't gouge into the fiberglass surface.
2. Once everything that's going to chip off is off, move on to using a coarser emory cloth. I like using a piece big enough that I can fold it over and have rough on both sides, and then still wrap around the oar. Run up and down until it looks like all the clear coat is gone.
3. If you're picky (like I am) move onto a fine grit emory cloth and use water with it to get a smooth surface. This shouldn't take too long, compared to removing all the old stuff. Worth the extra step, to me- make 'em beautiful!
4. Wipe down the oars with clean water and a clean rag. Let them dry completely. I like to hang them up for this step. tie some webbing around something on the ceiling, you'll want enough webbing hanging down that you have about a foot to tie the oar on by the handle, and then the bottom of the oar (without blade) is 6"-12" off the floor. Clove hitch the free end of the webbing around the handle of the oar.
5. With paper or cardboard under your oars, put on the first coat of Helmsman Spar Urethane. Brush it on thin, not too thick. It'll look like the oar is nice and wet, but shouldn't drip (much). Once it starts drying, don't keep fiddling with it- just stop brushing. Like with glue for patching- once it starts to get sticky, stop with the brush! You might get a few drips, but try to avoid. Let dry completely. Probably overnight.
6. With the fine grit emory cloth, give it a slight scuffing up, and wipe it down clean. Let dry if you used water. Another coat of same stuff. Let dry completely.
7. Scuff, clean and dry once more. One more coat. Let cure at least 24 hours- up to a few days if you have the time.
8. Take care of any drips that have hardened at the bottom of the oar. Either sand them off or use a razor to carefully take off any excess. Also at this time take care of any drips in the hole where the blade button goes. Take care not to chip up your new finish too badly.
9. Done! Treat 'em nice and that finish should last a few years. Slide them in and out of the trailer and drag them over hard edges a lot, and they'll last a season.
It sounds like a long process, and it kind of is, but it's not too bad. The most labor intensive part is step 1 and 2. After that, if it's somewhat warm where you're doing this, you might even be able to get a coat on first thing in the morning, and then last thing right after dinner (12 hours between coats).
The urethane also comes in a spray can. For completely refinishing oars (like the black ones) I'd stay away from this. However, for upkeep, say, mid season, or to do every season to prevent too much wear on clear coat that is still pretty decent, the spray is great. For spraying touch-ups I would use the fine grit emory cloth to scuff it all up, hang, let dry, and spray on a couple coats an hour or two apart. This is something I'd do with the new white oars, also. It's much easier to do this once or twice a season to keep up with the chips than to let them get real bad and have to remove all the old finish.
Here's a link to the product that I've used, and that Cataract Oars recommends:
Minwax Helmsman Spar Urethane - Exterior Polyurethane Finish | Minwax
I've found it at Home Depot before.
I've tried to be thorough with the instructions, so don't let them scare you away- it's really pretty easy and straightforward, just takes some time and attention to details, and a little bit of good judgement (is it dry enough to scuff and do another coat yet?). Should have those baby's looking great again in no time! Also, on step 1 and 2, I'm very thorough, but if you don't take all the old finish off, that's OK. Just be sure that all that's going to come off easily is off and you have a good surface for the new urethane to bond to.