My family and I were lucky enough to get the opportunity to sail the Whitsunday Islands in Queensland, Australia this April. We rented a sailing catamaran for our trip, specifically a Seawind 1000 XL, named the Lulu, from Whitsunday Escape. We also hired a skipper for our trip, Chris, who made a trip a real treat. A catamaran is the Winnebago of sailboats, but for a few nights at sea with novice sailors, it was the perfect choice.
Given the challenge of keeping electronics dry on a sailboat, particularly with winds that consistently blew above 25 knots during the day, I ended up using my iPhone while were were underway or during our excursions. My DSLR came out morning and evening, when we were docked and the winds were calmer. One of my sisters kindly bought all of us Vansky waterproof housings for our iPhones, which generally worked quite well. I did notice the occasional problem with sunspots when shooting toward the sun as the camera caught the light bouncing off the waterproof housing. Additionally, I did notice that the iPhone auto-focus had infrequent challenges with the addition of external sleeve, but given how frequently I was cleaning salt spray off the Vansky, it was a smart choice. We appreciated the lanyards to help secure our phones during the frequent jumps into and out of the dingy. That additional feature ensured non of us tested the ability of the Vansky to float! I kept my DSLR in a standard dry-bag. While I did pack water absorbing pouches, I probably could have gotten away without them.
The sunsets each night just blew us away. I don't know if there is a scientific reason that sunsets at sea are so spectacular, of if we just got lucky. While I don't usually bother with a lot of post processing (who has time?) I did find that I needed to apply a graduated filter to the sunset photos in Lightroom to eliminate the blow out occurring near the horizon.
For non-photography related tips I refer you to my sister's blog since she already did an excellent job of capturing the details: <http://relocation-to-melbourne.blogspot.com/2015/06/sailing-whitsunday-islands.html?spref=tw>
Enjoy!