Everything on and over the deck: cleats, winches and hardware, seating and cushions, biminis and sprayhoods, and the covers that keep the weather out of a boat while it waits for you.
A bimini is a fabric canopy on a folding frame that shades the cockpit or helm from above. It has no sides and no windscreen, so it does nothing about spray or wind; its whole job is sun. Biminis appear on sailing yachts over the cockpit, on centre consoles and bowriders over the helm, and on pontoon boats over the deck. Most fold flat aft on their frame in a minute, and that folding is the point: a bimini left up in a strong wind is a sail.
What is the difference between a bimini and a dodger?
Position and direction. A dodger, called a sprayhood in Britain, sits at the front of the cockpit over the companionway, with a clear window and sides, and stops spray and wind coming aft over the coachroof. A bimini sits over the back of the cockpit and stops sun coming down. Many yachts carry both, joined by a connector panel, and a full cockpit enclosure adds zipped side and rear panels to turn the two into a room.
What is the best fabric for a boat cover or bimini?
For anything that lives outdoors all season, solution-dyed acrylic of the Sunbrella type. The colour is in the fibre rather than on it, so it does not fade, it breathes, and it typically gives 8 to 10 years in temperate sun, less in the tropics. Vinyl-coated polyester is fully waterproof and cheaper but traps moisture and cracks with age, which suits a trailer or storage cover better than a bimini. Whatever the cloth, ask what thread it is sewn with; the thread usually fails first.