Most worlds and ship decks have normal weight. Some worlds pull harder, some pull less, and open space has no pull at all.
Normal. Where: Most worlds. Ship decks while the helm runs.
Light. Where: Small moons, the floating rock islands of Skerry, a ship whose helm has stopped.
Heavy. Where: Some mining rocks and heavy worlds, such as the home rocks of the Grund and the Gorr.
None. Where: Open space outside any air bubble or world.
Your jump distances are doubled.
You can carry and lift twice as much.
You take half damage from falling.
The long range of thrown weapons is doubled.
Your Speed drops by 10 feet.
Your jump distances are halved.
You can carry and lift half as much.
Falling damage is 1d6 for each 5 feet fallen, in place of each 10 feet, up to 20d6.
The normal and long range of ranged weapons is halved.
At the end of each 8 hours of hard work or travel, make a DC 10 Constitution saving throw. On a failure, you gain 1 Exhaustion level.
Getting Used to It. After 7 days on a heavy world, a creature no longer makes the Constitution saves. Grund, Gorr and Gorrin grew up in heavy places and have Advantage on these saves.
A creature with no Fly Speed can move only by pushing off a surface or pulling along a line or rail. When it pushes off, it moves in a straight line up to its Speed and keeps drifting at 30 feet per round until it reaches something.
A creature that is not holding on to anything or standing in Grip Boots has Disadvantage on melee attack rolls.
Falling does not happen. Nothing falls.
See the No Weight rule in the Air Bubbles and Open Space rule.
While a helm runs, the deck inside its air bubble has normal gravity, and down is toward the deck. When the helm stops, the deck has light gravity until the helm runs again. Grip Boots let a creature walk on walls, masts and the underside of a hull at half speed in any gravity.