A boat stand (aka jack stand or poppet) is used on land to support the port and starboard sides of a boat while the weight of the boat rests on keel blocks or keel stands. A typical boat stand has 3-4 supporting legs and a central strut that contains a threaded rod with a pad on top.
Boat stands come in a variety of sizes, heights and angles, and are available with flat or V-shaped pads. The two main types of boat stands are powerboat stands and sailboat stands. Typically, sailboat stands have an angled center strut and powerboat stands have a straight, vertical center strut. A keel stand can be used under the keel to support the full weight of a boat.
While it may seem obvious that you should get boat stands based on the type of boat you own, that's not necessarily the case. For example, a powerboat with a deep V-bow would use angled sailboat stands at the bow and powerboat stands at the stern. It's important to choose boat stands based on the angle formed between the hull and the boat stand's center strut. The threaded rod from the top should enter the stand's center strut at approximately a 90 degree angle to the boat's hull.
The type and length of your boat determines the number of boat stands needed. Position a pair of stands (one port, one starboard) every 8 feet. In general, for a powerboat or motorboat, you need at least four stands (two on each side, under the chines); for a sailboat, you need at least five stands (two angled stands on each side and a v-stand under the bow). Use additional stands if you're in an extremely windy area, or if you're leaving a sailboat mast in place. In addition, a boat with excessive overhang will require extra stands to support it.
Sailboats typically need one pair of angled stands every eight feet, plus a v-pad stand to cradle the bow. The one exception is a full-keel sailboat, which may not require a bow stand. Use extra stands if the mast is up, if you're in a windy area, or if you have a fin keel sailboat.
For a powerboat, you need one pair of boat stands on each side of the hull, every eight feet along the length of the boat. If using keel stands to support the weight instead of keel blocks, place one keel stand every ten feet along the length of the keel.
To figure out what size stands you need, add the draft of the boat (in inches) to the height of the blocks being placed under the keel, then subtract six inches.
Make sure the ground is solid and fairly flat. Place a plywood base under each stand or a small piece of plywood under each leg to spread the load evenly and keep the stand legs from sinking. This is especially important to do on loose ground or asphalt, which can soften in the heat.
After a boat is pulled out of the water on a travel lift or trailer and placed on flat ground on keel blocks, the boat stands are placed against the port and starboard sides of the boat. Boat stands keep the boat from falling on its side, but they're not designed to support the full weight of the boat. Using boat stands is a balancing act, done by placing them one pair at a time, every eight feet, on opposite sides of the boat. The tops of the boat stands should rest against the hull. For sailboats, secure each port/starboard side pair of stands with a length of safety chain. Refer to the stand manufacturer's directions for placing and tightening stands and safety chain.
A boat block is a wide, thick, rectangular, square-cut piece of pine timber. It's made especially for safely and securely supporting the entire weight of a boat, along the centerline, under the keel.
A keel block is the same as a boat block that's placed under the keel. However, a more convenient way to block a boat is to place keel stands under the keel, every 10 feet. A keel stand has a threaded center rod with a pad on top that can be raised to rest flat against the bottom of the keel.
To block a boat, it's put on blocking piles, on flat, solid ground, after it's been pulled from the water on a trailer or travel lift. A blocking pile consists of three blocks - two large ones, placed parallel to each other, and a smaller block placed across the top, on which the keel will rest. Typically, you need a minimum of two blocking piles under the centerline of the keel to keep the boat from rocking fore and aft. Check your owner's manual for details. To avoid stress on the boat, position keel blocks under bulkheads. If desired, the height of the blocking piles can be adjusted for drainage, but for stability, the piles should be as low to the ground as possible.
Safety chain (3/16" minimum) is used to secure each pair of stands on opposite sides of a boat. There's a place on each boat stand to attach the safety chain.