I know of only one marina where I got permission to move stands, with the
advice "just don't move them all at once". I do a lot of
boat work so the manager felt comfortable. However, I went and found an expert and got a lesson on how to move them. (There are many steps/nuances, involving chain tensioning and which way to point the longer leg, for instance.) Then I moved them with the expert by my side, while he corrected me.
So even if you have permission, it's not something to be taken lightly. (And I'm an
engineer and could diagram each and every force involved.) Best to spend the
money and have the marina move them.
As for the barrier coat, you don't have to recoat the entire
hull. Just sand the spots where the stands were, so the next layer sticks. The instructions to apply the next coat within XX days are for if you aren't
sanding. (And I always clean the area with Xylene too. Not sure you have to, the instructions might say something different too.)
Note this last time, I took a dried/hardened block of barrier coat, viced it into a workmate vice, and sanded it. I caught the sandings/powder in a paper bag. (The spinning
sanding wheel doesn't affect the paper bag that much when it contacts it.)
I added the powder to a batch of barrier coat and it made a great filler with the consistency of peanut butter. This helped to fill the very bottom of our iron
keel. I think that normally barrier coat flows such that a void in the underside will get worse as the wet barrier coat flows down away from where you really want it, making the ridges around the void proportionately higher. Using this filler
solved the problem.
Finally, watch your temperatures. If you have to launch early (or if you are launcing next week), you might want to invest in a
cheap tarp to put around the areas you are coating. With some space heaters and masking tape (to hold the tarp up), you'll be able to heat-up the enclosure and get
work done during colder
weather. Barrier coat needs warm temperatures to cure, and you'll be putting on several coats. The difference between waiting an hour (in an 80 degree enclosure) and waiting a day (in a 60 degree enclosure) is dramatic. Or just wait until some dry days in spring.
Regards,
Brad