One of the questions we often hear is "What type of vinyl can I put on a boat?" and often people refer to "marine grade vinyl." Some people refer to cast vinyl as "Marine Grade" but that's not really an accurate term. Part of the confusion is caused by manufacturers who list certain vinyl for use with Marine applications. This is a recommendation and what they say the products are commonly used for, not that the vinyl is "Marine Grade" vinyl. The same manufacturers usually also have vinyl they recommend for wall graphics, but it doesn't mean the vinyl is "wall graphics grade" vinyl, it's their suggested usage for the product. You'll also notice that these higher-grade films are recommended for "General Signage", but removable vinyl is not listed. Can removable vinyl be used for general signage? Sure it can, it may not last as long but can certainly be used. Just as removable vinyl not being listed doesn't restrict it from being used for such application, permanent calendered vinyl not being listed under "Marine Graphics" doesn't restrict it from being used on a boat--most of them all have the exact same adhesive, anyway.
Cast vinyl is usually slightly thinner than calendered, perhaps 2mil vs 3mil. Cast vinyl is a higher quality vinyl than Calendared vinyl because of the manufacturing process. To put it in simple terms, cast vinyl is sort of turned into a liquid and poured out so it's "cast" into sheets. Calendared vinyl is more or less put through rollers and squished out into sheets at a lower temperature and is less forgiving about contouring. Cast vinyl is more pliable and can be used over contoured shapes like creases or rivets without stretching back into it's original shape. Cast vinyl is preferred for things like car wraps.
There's a lot more to it but that's it in a nutshell. In short, calendered vinyl like StarCraft HD will work fine on a boat. If you have to put vinyl over contoured shapes or cover/wrap large areas, cast vinyl would be a better choice and it will generally last longer but calendered isn't going to fall off when it gets wet or anything. Likewise, Styletech, Siser EasyPSV, and StarCraft Magic are also permanent adhesive films that can be used on a boat, as well. Be aware that non-solid color films such as glitter or metallics may have a reduced life expectancy in harsh UV conditions. Fluorescent colors are not UV safe and will fade within weeks or months, usually.
