Before ordering custom mattresses for our Beneteau 393, we talked with three different vendors at the Annapolis Boat Show. While the spring versions are not bad and are powder coated to minimize the potential for rust, all three vendors agreed that the marine environment will ultimately rust. All three vendors also agreed that the memory foam versions provide excellent comfort, but my boat is located in Texas. All three vendors agreed that memory foam mattresses tend to hold heat, thus not the best option for our environment. Equally, all three vendors agreed that the latex mattresses are close in comfort to the memory foam, are resistant to mold, and do not hold heat like the memory foam. We ultimately ordered two latex mattresses with pillow tops. The comfort is remarkable and we consider this purchase one of the best we have made for the boat. The only mistake we made was in the thickness of the foam we ordered. Most vendors provided options for 6, 7 or 8" foam. The logic was that if 6" is comfortable, 8" would be better. We discovered that the 8" adds considerable weight to the mattress (our aft cabin is between a queen and king size) and even with the hinged design, it is a bear to get in and out of the cabin or to even fold if we need access to the space below the deck of the bed. I would highly recommend that you save both money and your back and order the 6" foam with pillow top.