The latest buzz in the US is wrapping boats (particularly ski boats) with digital prints, or even just cast vinyl colours. It works out cheaper than painting a custom design, and even just from a maintenance perspective it is good value.
There are a few problems with wrapping a boat - but don't worry, they are easily solved! The first is film selection, you should always use a cast film. ANY shrinkage could cause a point of entry for water. A fast power boat such as a ski boat or even a run-a-bout will force water into any available channel and literally water-blast the decal off the hull!
It follows also that films with air-egress channels such as 3M IJ180C or Arlon DPF6000X will also potentially let water in underneath the film, so overlaps must be wide, edge sealers should be used, and the film should be given at least a fortnight to settle before the boat is put in the water. The special adhesive in Arlon DPF6000X will actually fill in the air-escape channels after 7-10 days in the sun.
It might be easier in some cases to use either 3M IJ380 or Arlon DPF6000, both of which are premium quality cast printing films without air-egress channels in the adhesive. For plain colours, 3M 7725, Calon II or Avery 900 series are all suitable.
Any waxes or silicones should be removed before attempting to apply vinyl decals or wraps. As always, surface prep is the most important part of any application. Chips and scratches in the gel-coat should be filled prior to application.
Another problem with boat hulls is their complex shape. What might appear to be a straight line in profile could actually be a sharp curve, or even an 'S' shape! For this reason, more so than on vehicles, it is recommended that a template is used. This is not nearly as hard as it sounds and full instructions for constructing a template can be found here:
http://www.nbm.com/digital/edition/wr/08/01/MR/WRJan024
One of the advantages of selling boat wraps is that you might also be able to sell a matching vehicle wrap like the author in the article linked to above. While Australians aren't as crazy about that sort of thing as Americans tend to be - have you ever noticed that people with fast boats or jet-skis do tend to be more into that sort of thing than the rest of us? Sure, people usually turn their cars over faster than their boats, but a wrap is easily removed when the car is to be sold. I predict we will see more of this in the future now that it is more practical. People with "fast toys" love to customise!