Also...I see that you can find Guvit for about $45 for a quart (which covers about 25-35 sq ft) and $85 for a gallon which covers 100-130 sq ft) plus shipping. I don't see the value in spreading it all over the inside of my hull where there is no potential for leaky rivets, and would only use it as a "spot" application on the rivets that are below the waterline. That said, I think a quart would do the job for me. I read that if the Gluvit is exposed to direct sunlight, it should be top coated with a paint etc..