I've done a lot of coating and varnishing on (bigger) boats and I cannot stress enough that it's extremely important to stick to the manufacturers application guidelines. This is especially the case with the more expensive products due to their highly sophisticated physical features.
Do not apply if your shop is too cold, too hot, too humid (do not use gas burners for heating, the reaction generates way too much H2O molecules). Also, changing temperatures during the cure can be a problem - if it can't be avoided make sure they stay within the allowed range throughout.

I'm writing this having learnt it the hard way: Some time ago I coated my mahogany racer with a 2-component PU high gloss varnish ($100/litre). After 2 weeks it was stilly tacky like chewing gum. It turned out the manufacturer had send me solvent instead of hardener and I had to remove the goo with a scraper from my brand new boat. It took 3 days and left a lot of scratches behind.