If you purchased the boat new, there should have been cleaning instructions for the vinyl. If you purchased it used, I'd suggest reaching out to Mastercraft and see what they recommend. It's new enough they should be able to assist.
Four Winns had this concoction that I have used with no issues (**This was on my Four Winns so I strongly recommend testing in a small patch first as your mileage may vary with this!!)
(1) teaspoon ammonia
1/4 cup Hydrogen Peroxide
3/4 cup distilled water
Rinse with water and dry....I always used a vinyl conditioner after this as well.
Of Note: They, Four Winns, specifically called out against: Simple Green, Formula 409, Amorall, Son-of-a-Gun, Bleach / Baking Soda, Tar Remover, Fantastik. That being said, I used diluted Simple Green with no ill effects over 12 years of ownership - vinyl still looked like new!