Glenn Ward wrote:

OK, explain please. I have a canoe that is quite dull on the bottom
from being exposed to too much sun.
Which do I want?

You may need both, depending on how badly oxidized the gelcoat is.
Rubbing compound (typically orange in color) is coarser than polishing
compound (typically light tan in color). Use the former to remove deep
oxidation and the latter to produce a high gloss. If the surface is in
really bad shape, you'll have to wet sand it first, starting with 320 or
400 grit and progressing to at least 800 (1200-1500 is preferable)
before switching to the compounds and a buffer.

--
Regards

Brian