Shift Gravity Plane
(Alteration, Enchantment)

Range:  100 yards per level
Components:  V, S, M
Duration:  1 hour per level
Casting Time:  1 round per ton of ship
Area of Effect:  One ship
Saving Throw:  Special

This spell causes the gravity plane of a ship to shift by up to a maximum of 20 feet per level. This means that if a gravity plane of a ship had passed through the keel of the ship it could now be shifted up or down (if cast by a 16th-level caster) by up to 320 feet upward or downward. If it were pushed upward it would cause everything to fall upward until it either strikes another solid object above it or it falls upward until it meets the gravity plane whereupon the thrust will be reversed and so on. If it were shifted downwards the crew would probably not notice anything unless the gravity plane had passed somewhere through the ship amidships. The later effect would only cause some problems if another ship would pass close enough to the affected ship so that their gravity planes would intersect. In that case the larger ship would cause the ship with the lower tonnage to instantly adjust its gravity plane to the larger ship. Thus, this effect could cause quite some damage to either ship in combat.
This spell requires a scale made from mithril which is severely imbalanced by having one arm made extremely thick and one arm extremely thin. This imbalance has to be countered by applying one ancient copper coin (more than 1000 years old) to the lighter side of the scale per ton of ship to be affected. The scale has to be large enough to contain all coins at once. The scale itself has to cost no less than 10,000 gp.

