7.1 Standing Water	7.1.1 Lakes and pools	7.1.2 Resevoirs	7.1.3 Seas	-
7.2 Flowing Water	7.2.1 Passage Diameter	7.2.2 Impassable	7.2.3 Narrow	7.2.4 Average
-	7.2.5 Wide	7.2.6 Percentage of Flow	7.2.7 Rate of Flow	7.2.8 Stagnant
-	7.2.9 Placid	7.2.10 Medium	7.2.11 Rapid	7.2.12 Cascades
-	7.2.13 Waterfalls	7.2.14 Damming the Flow	-	-
7.3 Water Temperature	-	-	-	-
7.4 Access to Undergound Waterways	-	-	-	-
7.5 Underground Water Travel	7.5.1 Movement Rates	7.5.2 Ceiling and Depth Requirements	7.5.3 Proficiency Effects of Boat Movement	7.5.4 Collisions
-	7.5.5 Drop-offs	7.5.6 Bailing	7.5.7 Capsizing	-
The Underground Enviroment	-	-	-	DSG

    The rivers, lakes, and streams on the underearth provide a rare
opportunity for unimpeded transportation through the Underdark.
These waterways are not uncommon, but only a small proportion
of them are truly navigable.  Many of the rivers and
streams run swiftly, and often plunge and roar through caverns
that are completely filled with water. This makes methods of river
transportation used on the surface virtually impossible.

Denizens of the Underdark, and adventurers who visit there
regularly, have worked out a number of ways to deal with treacherous
underground waterways. Some of the techniques closely
resemble those used for surface water transportation, while others are unique to the sunless environment.

Water underground is found as flowing water (brooks, streams,
and rivers) and standing water (pools, reservoirs, lakes, and seas).

Water temperature is often a valuable clue as to the origin of an
underground waterway’s flow.

<
RIVER STATBLOCK
WS = water speed (1 to 40)
FQ = fishing quality (poor, fair, good)
>

7.1 Standing Water
 

7.1 Standing Water

7.1.1 Lakes and pools

7.1.2 Resevoirs

7.1.3 Seas

7.0 Underground Waterways

Standing water gathers wherever the flow of water into an AREA
becomes so dispersed that a current is no longer readily detectable.
Although water may still flow through an underground lake,
the current travels so deeply or slowly that it cannot be observed.

The characteristics of underground lakes and seas are very different
from their counterparts on the surface. The absence of
wind is a significant difference, but the overhanging ceilings
make an even more pronounced impression. If the ceiling over an
underground lake, pool, or sea is so low that it touches the surface
of the water or leaves only a few inches of clearance, normal
boat travel is impossible.

The absence of wind means that sailing is virtually unheard-of
underground, except in those rare instances where the ventilation
is ample enough to create a wind capable of moving a boat.
Waves are practically nonexistent. Thus, underground lake and
sea shores are not eroded by wave action, although magical
forces or falling objects can cause occasional waves. A cave-in
somewhere above or next to a lake often forces a powerful wave
outward, much like a tsunami on the surface. In fact, the earthquakes
that cause tsunamis in the outside world often produce
similarly destructive waves in the Underdark.

The action of such waves is often amplified and confused by
the confining walls that enclose most underground bodies of
water. If a large wave starts in a small underground body of water,
a deadly and chaotic surface of choppy waves can last for many
turns. The exact duration of such disturbances is left to the DM’s
discretion, since it depends on the force that created the original
wave and the size of the AREA enclosing it.

Other causes of waves include animal, monster, and humanoid
activity, and streams flowing into a standing body of water. Characters
confronted with waves on an otherwise still body of subterranean
water are wise to determine the source of the
disturbance.

7.1.1 Lakes and pools make up the majority of underground bodies of water.

They differ in size (lakes are larger), but both contain
fresh water.

Large pools and lakes often support a wide variety of living
creatures. Even small pools may hold such creatures, as long as
a sufficient food supply is available in the water, or (in the case of
amphibians) in the surrounding area.

Lakes and pools can be found at nearly all depths of the Underdark,
from a few hundred feet below the surface to the farthest
depths of the world. If a lake or pool has a stream or spring flowing
into it, the water is almost always safe to drink.

Eldath (goddess of pools)

7.1.2 Reservoirs are commonly created by the intelligent denizens
of the Underdark. As might be expected, each reservoir is contained
by a dam of some kind-but this dam is not always built
along the side of the reservoir. It may, in fact, be located at the reservoir’s
bottom, and serve much the same function as a cork in
the bottom of a leaky bucket.

Occasionally a reservoir is formed as a secondary result of
some race’s attempt to regulate the flow of water for irrigation,
transportation, or defense. In any event, reservoirs have most of
the same characteristics as underground lakes and pools.

7.1.3 Seas lie in the deepest depths of the Underdark.

As on the surface,
seas contain salty water heavy with minerals that have been
dissolved from the surrounding rock. Because of their age, seas
are almost always huge in comparison to other underground
bodies of water.

Whole races of intelligent and unintelligent creatures inhabit
the seas of the Underdark. Some of these seas are cold, vast,
and deep. Others lie so close to geothermal heat sources that
their waters are warm and the air surrounding them is heavy with
steam.

These seas are so far away from the surface of the world that
they are rarely seen by outsiders. Even if a navigable path is
somehow found through a long network of underground streams
and rivers, a return trip of such a distance without the benefit of a
current is almost unthinkable.

7.2 Flowing Water

7.2 Flowing Water	7.2.1 Passage Diameter	7.2.2 Impassable	7.2.3 Narrow	7.2.4 Average
-	7.2.5 Wide	7.2.6 Percentage of Flow	7.2.7 Rate of Flow	7.2.8 Stagnant
	7.2.9 Placid	7.2.10 Medium	7.2.11 Rapid	7.2.12 Cascades
	7.2.13 Waterfalls	7.2.14 Damming the Flow	-	7.0 Underground Waterways

Flowing water is more commonly encountered underground than standing water.
Indeed, it is flowing water that has shaped much of the underground environment.

The characteristics of a flowing body of water are determined by three significant measurements:
    * the diameter of the waterway,
    * the percentage of the passage that is filled with water, and
    * the rate of flow.

7.2.1 Passage Diameter
The following four categories describe the various types of passages
through which underground waterways flow.

Impassable waterways are too narrow for a fully equipped
party of PCs to MOVE through. These passages may be as narrow
as a few inches--small cracks that spew forth considerable volumes
of water--or they may be wide enough for characters to
wriggle through. At least part of an impassable waterway must be
less than three<3> feet in diameter.

Narrow waterways include streams && rivulets. A narrow
waterway follows a path less than 20 feet wide, and is generally
less than three<3> feet deep.

Average waterways include streams and small rivers from 20
to 60 feet wide. Although occasionally shallow enough to wade
in, average waterways are usually four<4> to eight<8> feet deep.

Wide waterways include all areas of flowing water more than
60 feet wide. The depth of such a waterway is generally greater
than eight<8> feet, at least in the center. The water near each bank is
often considerably shallower.

Occasionally an artificially constructed underground waterway
may be encountered. These include canals, which allow water
transportation between areas, and aquaducts, which move water
from one location to another. The underground races also use
flowing water to turn water wheels, creating a power source for
fans, pumps, and other machinery. In some locations, waterpowered
pumps are even used to operate locks on underground
canals.

7.2.6 Percentage of Flow <(PF)>

This characteristic is reflected by a % #.
If the tunnel || passage containing an underground waterway is examined in cross-section,
the PF (percentage of flow) # equals the amount of the passage that is filled with water. <alt>

A river passage with a 50% flow is half-full of water && half-full of air.
Depending on the overall size of the passage, it might be possible for characters to swim || boat through the waterway.
A passage with 100% flow is completely filled with water and impossible to boat through.

7.2.7 Rate of Flow <(FR=Flow Rate)> <(rule of thumb: FRx2=Move")>
 

0 = Stagnant	1-2 = Placid	2-6 = Medium	6-12 = Rapid	12-30 = Cascades
30-40 = Waterfalls	-	-	-	Flowing Water

The rate at which water flows through an underground stream
determines a number of other characteristics of the waterway:
how quickly the riverbed erodes; how quickly the river loses altitude
in its travels (remember, all rivers flow downhill to some
extent); how much noise the river makes; and how dangerous the
river is to travel upon.

The maxim “still waters run deep” is more than an idle phrase.
The deeper a given body of water, the more slowly it runs. Thus,
areas of savage && churning rapids tend to be rather shallow;
the same amount of water moves much more gently along a deep
riverbed.

In game terms, rate of flow is quantified as a number ranging
from 1-40. Waterways with a current of 1 are barely moving, while <b>
those rated 40 tumble down as waterfalls. A completely stagnant
body of water receives a 0 rating. The actual movement rate of
the current can be calculated by multiplying the flow rate by 20
feet per round.

Stagnant water seems to have no flow whatsoever (flow rate = 0).
Stagnant water is encountered in a stream or riverbed when
there is no downhill flow. Instead, the water collects in pools and
low spots in the riverbed. While travel along a stagnant body of ,
water is not threatened by flow, it may be difficult if the water is
too shallow to support a boat.

Placid water usually has a noticeable flow (flow rate = 1-2).
It is sometimes necessary to drop bits of wood, dust, or other floating
objects into the water to determine the direction of its flow.
Placid water is often encountered near the mouths of streams or
rivers or in lakes.

A placid waterway has a barely perceptible drop in altitude as it
flows along, often no more than 10 or 15 feet per mile. Any rocks
or other obstacles in the water can be easily avoided. The rate of
flow of such a stream is 40 feet or less per round.

Medium flowing water is the most pleasant for traveling downstream (flow rate = 2-6).
The water flows along at between 40 and 120 feet per round, descending only slightly on its course.
A river with a medium flow may drop as much as 30 feet over the course of a mile.

Travel along this type of waterway is relatively safe, but characters
must keep a lookout for potential obstacles such as rocks
protruding from the water. With care, obstacles are easily
avoided, but characters not paying attention may be drawn into
an unfortunate collision by the force of a medium flow of water.

A river with medium flow has few if any sudden drop-offs. When
PCs travel along such a river, the DM should roll ld6 for each mile
traveled. On a 5 or 6, a drop-off of 1d3 feet is encountered somewhere
in that mile.

Rapid flowing water is more commonly called rapids (flow rate = 6-12).

The water spills and rolls along with a muted roar, crashing
into and around any obstacles in its path.
Water flowing through rapids travels more than 120 feet per round--sometimes as much as 240 feet per round.
<FR6=12", FR7=14", FR8=16", FR9=18", FR10=20", FR11=22", FR12=24">
The descent of the stream bed ranges from 30 feet to as much as 200 feet over the course of a mile.

The sound of rapids can be heard by characters and creatures
within 1,000 feet.

Traveling upstream along rapids is impossible unless powerful
magic is employed. Traveling downstream along rapids is dangerous,
but possible. Certain kinds of boats, such as kayaks, are
more suited to rapids than most standard boats. Characters who
try to boat down a rapid stream without possessing boating proficiency
will find themselves in great danger.

Rapids generally have many sudden drop-offs during the course of their flow.
For each mile that the PCs travel along a rapid stream, the DM should roll 1d6.
A result of 6 means that no significant drop-offs occur during the mile.
A result of 1-5 is the number of drop-offs encountered.
Each drop-off falls 1d4 feet.

Cascades are steeply dropping portions of a river where the water tumbles from one level to the next in a foaming series of short drops (flow rate = 12-30).
A cascade is much like a stairway with water running down it.
The thundering roar of a cascade is usually audible at least a mile away from the river.

Water spilling down a cascade travels at anywhere from 240 to
600 feet per round. The waterway descends at a slope of at least
200 feet, and perhaps as much as 1,000 feet, in a mile. Travelling
upstream against the force of a cascade is impossible; travelling
downstream might be possible for a lucky character with boating proficiency who is in a kayak.

A cascade, by its very nature, includes many drop-offs. If PCs
chance to travel down a cascade, the DM should roll 3d6 for each
mile traveled. The result is the number of drop-offs encountered
during the course of that mile. Each drop-off is 1d8 feet high.
 

Waterfalls

Waterfalls represent flowing water at its fastest and most powerful (flow rate = 30-40). <(FR=30-40)>
A waterfall is created wherever flowing water falls freely to a lower level instead of flowing along a bed.
A long stretch of waterfalls, with rapids or cascades between them, is still considered a waterfall.

The {SPEED} of water plummeting over a fall is at least 600 feet per round.
The exact speed depends on the number of steps in the fall.
While it is theoretically possible for a waterfall to plunge thousands of feet straight down, most waterfalls include areas where water flows forward along a bed.
For purposes of this rule, anywhere the water plunges at a slope of more than 1,000 feet per mile is considered a waterfall.

The nature of a waterfall makes it impossible to control a boat travelling over the fall.
Although characters in boats might survive a plunge over a waterfall, such survival is more a matter of luck than skill.

Eldath (goddess of waterfalls)

Q: Can a waterfall (or other loud
sources of noise) negate the casting
of a spell with a verbal component?
    Also, can a character cast a hold
person on a character who has just
gone over a waterfall to hold him
under water and drown him?

A: Nope and nope.

To negate a spell with a
verbal component, one needs to stop the
spell-caster from speaking. It doesn't matter
whether the TARGET can hear the words
-- all that matters is that the words are
spoken. The tremendous din of a waterfall
would not affect a spell that requires a
verbal component to cast, but a silence
spell or a gag will prevent the spell from
being cast. A waterfall does, however,
drown out the noise of shriekers and the
singing of harpies (the DM must decide
how far from the waterfall one must be
before normal hearing is restored).

A hold person spell doesn't work that
way. It only prevents a person from voluntarily
moving, and cannot stop the action
of the moving water (and the body's natural
buoyancy) from bringing the person to
the surface, where he can float (and
breathe).
(118.58)

Damming the Flow

Underground waterways are as susceptible to damming as
their surface counterparts. Because of their confining environment,
damming underground rivers or streams often produces
dramatic results.

The success of a damming attempt by PCs must be adjudicated
by the DM. Is sufficient material available to fill the passage
to a suitable height? Is the water flowing so fast that any damming
material will be swept away?

If an underground waterway is dammed, it immediately begins
to back up and flood behind the dam. A DM confronted with this
situation must rely on accurate three-dimensional maps (see
page 114). The water may well be diverted into other parts of an
underground setting, filling rooms and making its way through
corridors and down stairways.

In an average waterway, water held back by a dam fills a 10-
foot cubic area (10 ft x 10 ft x 10 ft = 1,000 cubic feet) times the
waterway’s flow rate per turn. Thus, if an average-width waterway
with a current of five is dammed, the water backs up at a rate of
five 10-foot cubic areas (5,000 cubic feet) per turn. This figure
should be doubled for a wide waterway and quartered for a narrow
one. As soon as the water level reaches a height that allows it
to flow through another channel, it changes course to follow the
path of least resistance.

The strength of a dam is measured in Construction Point Values,
as shown on DMG pages 109-110. A single worker can construct
1d6 points of dam per turn. The current destroys a number
of points equal to the water’s rate of flow each turn, however, so
several characters must work together to dam rapid streams.

The Construction Point Values of completed dams equal 50
points on a narrow waterway, 150 points on an average waterway,
and 250 points on a wide waterway. Once a dam is completed,
water will not destroy it unless something specifically weakens
the dam or increases the water pressure. Once a dam begins to
leak, however, water destroys a number of points equal to half the
rate of flow per turn until the dam is washed away or repaired.

Water Temperature

Unless some external source of heat is contributing to the
water temperature, underground water is almost universally cold.
Although water rarely freezes underground, its temperature is
numbing to any characters who get soaked in it.

Some underground water flows directly from above-ground
sources such as shallow seas, lakes, and meandering rivers. If
the water is relatively warm when it leaves its source, it retains
this warmth for 1d4 miles.

Underground water can also occasionally be warmed by geothermal
heat sources-the same sort of heat energy that gives
rise to geysers and volcanoes. Depending on its proximity to the
heat source, such water might be only slightly warmer than the
usual underground waterway, or it might be so hot that a character
falling into it is scalded to death very quickly.

Characters immersed in water that is at or near boiling temperature
suffer 6d6 of burn damage per round spent in the water. No
saving throw is allowed, although characters with any kind of
magical protection against heat or fire gain a -2 per die of damage
(minimum of 1 point per die).

Characters only partially immersed in such water only suffer
partial damage. The DM must establish a proportional number of
d6 of damage based on what proportion of the characters’ bodies
is exposed to the water.

Water that is very hot, but not near boiling temperature, inflicts
ld6 points of damage to characters immersed in it. Characters
who are only partially exposed, or who have any kind of magical
protection against fire and heat attacks, are not affected. If the
water is no warmer than very hot bath water, characters suffer no
ill effects from the heat.

Access to Underground Waterways

The streams and lakes of the Underdark can occasionally be <{}?>
embarked upon directly from the surface. A meandering stream
may flow into a cave and disappear, or the far side of a mountain
lake may include a cave both high enough and deep enough for a
boat to enter.

More often, however, water flowing underground drops from
the surface in a series of cascades and waterfalls, or trickles
through a tunnel too narrow for characters to follow. In these
cases, characters must enter the underearth through a dungeon
or cavern and then find a suitable place to join the river below.

In rare cases, an underground river might actually return to the
surface. If a cavern or cave has been created in a mountain or
highland area, for example, the water might work its way downward
within the earth, but as it reaches the end of the higher elevations
it flows out of a cavern or tunnel to run again as a surface
stream. If the water is suitably placid, such locations can provide
opportunities for characters to gain access to an underground
waterway. Entering at a water outlet necessarily entails the problems
of traveling upstream along the water.

Once a waterway is located, an accessible shore must be discovered.
Underground lakes and seas are generally not surrounded
by the sandy beaches so common on the surface, since
without waves there is no force to grind the stone into sand. Such
bodies of water are more likely to be surrounded by sheer cliffs or
jagged boulders. Of course, in the inhabited portions of the Underdark,
it is likely that some intelligent creatures might have built
docks or wharves for their own use. It is even possible that these
creatures may have left a few boats lying around!

Streams and rivers are much more likely to be bordered by
smooth sand beaches that allow easy access to the water.

Because the torrents of rushing water serve as constant gouging
forces in their channels, riverbeds are gradually growing deeper
and enlarging their sandy beaches. This gradual deepening
means that it is not unusual for an access tunnel, which once fed
into a river below its surface, to now end with its mouth a dozen or
more feet above the river's surface.

An additional problem associated with underground waterways
is ceiling height. The water might be deep enough to support
the heaviest of boats, but if the ceiling drops to within a few
feet of the water, travel by boat is quite impossible.

Underground Water Travel

Travel by boat along the waterways of the Underdark involves a
different set of risks and obstacles than boating in the lakes and
streams of the surface world. Of course, some of the challenges
are similar, such as negotiating a rapid stream in a small boat, but
the inky darkness of the underworld changes the experience significantly.

Of course, the dangers presented by weather are generally
absent from the underground. On the other hand, low ceilings
and tortuously winding passages create problems not encountered
on the waterways of the surface world.

The problems involved in getting watercraft into the dungeon
must be handled in the specific campaign setting. Such
enchanted vessels as the folding boat are ideal for dungeon
adventuring, since they can easily be carried through narrow
passages, down stairways, etc.

Collapsible boats, while expensive and weaker than normal
boats, provide another means of traversing underground waters.
In inhabited or heavily traveled regions, characters might be
lucky enough to find boats used by creatures dwelling underground.
Such boats could possibly be borrowed, bought, or otherwise
acquired by the PCs.

If the party attempts to carry a boat with them into a dungeon,
the DM must make careful note of the dimensions of the boat, as
well as the size of the passages of the dungeon. In a tight series
of turns or bends in the passageways, it might be helpful to draw
a detailed map of the corridors and cut out a scale model of the
boat. It is then easy to see if the boat can fit through a given area.

Movement Rates

This section expands on the boat movement rates given in the
DMG, on page 54. Movement rates are given here in terms of feet
per round. In addition, rates for canoes and kayaks are added.

Table 21: BOAT MOVEMENT RATES *
 

Type of Boat	Normal Oar/Paddle	Max.** Oar/Paddle
Small rowboat	90 ft/r	120 ft/r
Coracle	30 ft/r	45 ft/r
Large rowboat	45 ft/r	60 ft/r
Small barge/raft	60 ft/r	45 ft/r
Large barge	20 ft/r	30 ft/r
Small canoe	120 ft/r	180 ft/r
Large canoe	90 ft/r	120 ft/r
Kayak	120 ft/r	180 ft/r

* Subject to the speed and direction of water flow.

* * A character propelling a boat at maximum speed is considered
to be working hard for purposes of the fatigue and exhaustion
rules.

Moving a boat from a stationary position to normal speed can
be done fairly quickly with most types of boats. The following
table expands on the DMG information on this subject:

Table 22: MOVEMENT FROM A STANDSTILL POSITION
 

Type of Boat	To Normal Speed	To Maximum Speed
Small rowboat	1 round	3 rounds
Coracle	1 round	3 rounds
Large rowboat	2 rounds	5 rounds
Small barge/raft	2 rounds	6 rounds
Large barge	5 rounds	10 rounds
Small canoe	1 round	2 rounds
Large canoe	1 round	3 rounds
Kayak	1 round	2 rounds

Whenever boat movement is calculated, it is important to
remember that this movement is relative to the water only. The
boat's movement rate must be combined with (either added to or
subtracted from) the water movement to determine the boat's
movement relative to land.

For example, in a stream flowing 60 feet per round, a canoe
traveling upstream at 90 feet per round is actually only moving 30
feet per round past the bank of the stream. The same canoe traveling
downstream streaks along at 150 feet per round, relative to
the stream's bank.

The same procedure for calculating the boat's acceleration is
applied in reverse to determine how long a boat will continue
coasting forward if its crew attempts to stop it.
 

Ceiling and Depth Requirements

All boats require acertain amount of room above and below the
water's surface. Table 23: Boat Draught and Ceilings lists the
requisite distances for various types of craft.

Table 23: BOAT DRAUGHT AND CEILINGS
 

Type of Boat	Depth Required	Ceiling Required
Small rowboat	1/2 ft	2 ft
Coracle	1/2 ft	3 ft
Large rowboat	3/4 ft	3 ft
Small barge/raft	3/4 ft	3 ft
Large barge	1 ft	4 ft
Small canoe	1/4 ft	1 1/2 ft
Large canoe	1/3 ft	2 ft
Kayak	1/4 ft	1 1/2 ft

The ceilings listed are the minimums needed for that type of
craft to pass unimpeded, assuming that cargo is kept below the
level of the gunwales and all passengers lie flat.

Proficiency Effects on Boat Movement

The movement rates listed for boats assume that at least one
character who is helping to propel the boat has boating proficiency.
The following penalties are incurred if no characters possess
boating proficiency:

Table 24: NONPROFICIENCY PENALTIES FOR BOAT USE
 

Type of Boat	Movement Modifier	Capsize Chance
Small rowboat	-30 ft/r	5%
Coracle	-15 ft/r	10%
Large rowboat	-15 ft/r	0
Small barge/raft	-10 ft/r	0
Large barge	-5 ft/r	0
Small canoe	-60 ft/r	20%
Large canoe	-30 ft/r	10%
Kayak	-60 ft/r	25%

The movement modifier is applied to each round of operation
at normal or maximum speed. The capsize chance is rolled for
each time a character enters or leaves the boat, and on any other
occasions the DM feels are risky. For example, if a canoe operated
by characters without boating proficiency should attempt to
turn around in astream with a mild current, the DM might declare
a capsize check. If the characters attempt to retrieve something
from the water, stand up in the boat, or do anything equally risky,
the DM may also require a check.

If at least one person with boating proficiency is present in the
boat, the capsize chance does not apply. If at least half of the
characters paddling or rowing the craft have boating proficiency,
the movement penalties do not apply.

All of these nonproficiency penalties assume that the boat is
moving through water of medium flow or slower. Riding rapids or
cascades is much more challenging, as mentioned on this page
and on page 48.

Collisions

A boat that smashes into a large boulder or rocky promontory
may suffer damage. Collisions are especially hazardous in the underground environment because of the constricted nature of
the waterways. In addition, the lack of light makes travel even
more dangerous than on the surface.

A boat that carries a lantern or beacon aboard can light the
water before it sufficiently to avoid collisions due to darkness. If
the light is snuffed, however, or the boat’s progress is especially
fast, the danger of smashing into a rock becomes very real.

In general, obstacles can be avoided if the range of vision of
the characters on board is greater than the distance the boat travels
in one round. (Infravision is sufficiently sensitive to the differences
between the water and its bed to navigate a boat.)

If the boaters’ vision does not extend far enough to avoid collisions,
the craft must check each round to determine if it collides
with anything, such as the bank of the waterway or a barely submerged
rock. Table 25: Collision Probability displays the chance
of a collision occurring.

Table 25: COLLISION PROBABILITY
 

Width of Waterway	Placid*	Medium*	Rapid*
Narrow	1%/10%	5%/20%	20%/40%
Average	0%/5%	2%/10%	10%/20%
Wide	1%/1%	0%/4%	4%/8%

* Number before slash is for a character with boating proficiency;
number after slash is for a character without boating proficiency.

A d100 roll against this table must be made each round that the
boat travels blind. A result equal to or lower than the percentage
listed means that the boat collides with an unyielding surface.

A collision does not necessarily inflict damage upon a boat, but
the faster the boat is moving, the greater the chance that damage
results from a collision. The base chance of suffering damage is
equal to 5% for each 30 feet per round of the boat’s speed. For
example, a boat traveling 90 feet per round has a damage probability of
15%. When a collision is indicated, roll d100 again and
compare the result to the damage probability.

If the d100 roll is equal to or less than the damage probability,
the boat sustains some damage from the collision. The exact
extent of the damage is determined by the difference between
the die roll and the damage probability, and is expressed as a percent
of the boat’s hull strength.

For example, if the roll for the above-mentioned situation was
05, this is 10% less than the 15% damage probability for the
boat. Thus, the boat’s hull has suffered 10% damage.

The actual effects of this damage are detailed on Table 26:
Boat Damage.

Table 26: BOAT DAMAGE
 

Percent Damage	Effects
01-05	Boat leaks slightly; will founder after 1d6 hours
06-10	Water pours in from a small hole; boat founders in 2d4 + 2 turns
11-20	Water pours in from 2d4 small holes; boat founders in 2d4 turns
21-45	Large holes in hill, boat founders in 1d6 rounds
46-60	Hull splits open and boat founders immediately
61-80	Boat breaks into 1d6 pieces
81-98	Boat splinters into many pieces
99-00	No damage!

Q: Is it my imagination, or is it too
easy to smash a boat to bits in underground
waterways (according to
the tables on page 48 of the DSG)?

A: It's your imagination. First of all, look at
page 47. You only roll on Table 25: Collision
Probability if the characters can't see
where they're going (if they're covering
more distance per round than the distance
they can see). Carrying a torch lets the
boaters see 30', so there's no chance of a
collision in water that's moving 30'/round
or less. If a beacon (described on page 56)
is mounted on the boat, the characters can
see 240' directly ahead of them. That
keeps them safe from mishap in any but
the wildest waters or in waterways that
twist and turn a lot.

The above points aside, traveling totally
blind through a medium-speed waterway
(up to 120' per round) in a passage 20-60'
wide gives the boaters a 10% chance of a
collision per round if they cower in the
bottom of the boat and hope for the best
(if a character with boating proficiency
steers, this chance drops to 2%). If a colli-
sion is indicated, the change of damage is
only 5% for every 30' per round the boat
is moving. You roll 1d100. If the resut is
less than the chance of damage, the boat
receives damage equal the damage chance
minus the d100 roll result, multiplied by
1% of the boat's hull strength (Table 26:
Boat Damage gives a qualitative result in
terms of how badly the boat leaks).

To sum up, taking a few simple precautions
(having a character on board who
can handle a boat, bringing a light source,
backing the oars if the water is moving too
fast, etc.) gives a good chance that the boat
reaches its destinatoin with only a few
dents. If anything, the system seems to be
too lenient considering that travel occurs
in confined quarters, with no natural light,
and in unusually rough, fast, and unknown
waters.
(118.58)
 

Drop-offs

Streams of rapid or cascading water often tumble over rocky
drop-offs during their course of flow, and this occasionally occurs
in streams of medium flow as well. These drop-offs present special
hazards to boaters, since they can cause a boat to capsize, or
can inflict collision-like damage upon it.

Every time a boat plunges over a drop-off, check for damage
just as if the boat was in a collision. The chance of damage is 5%
per one foot of the drop-off, however, and is not based upon the
boat’s speed. As with a collision check, the degree of failure
determines the extent to which the boat is damaged, with the
actual result determined on Table 26: Boat Damage.

Any time this roll is made and the result is 99 or 00, the boat
miraculously survives the fall undamaged.

The chance of capsizing is also 5% per one foot of drop-off. If a
capsize is indicated, however, and a character with boating proficiency
is aboard, any one character with boating proficiency can
attempt to make a Proficiency Check. Success means that the
character prevented the boat from capsizing.
 

Bailing

Characters who are not rowing or steering a boat can attempt
to bail out water that flows in from a ruptured hull. Bailing is considered
strenuous exercise for purposes of fatigue and exhaustion
rules, unless the boat is only leaking slightly.

A single character can bail enough water to cancel the effects
of one small hole in the hull. The character must have a suitable
container to scoop the water with, and must devote all of his time
to bailing.
 

Capsizing

A boat that capsizes tips over and fills with water. All loose
objects in the boat fall free, and must be recovered individually. In
rapidly moving water, recovery of scattered items is usually
impossible. The boat must be refloated before it can carry passengers
and gear again. It takes 1d4 rounds to refloat a capsized
boat.

Capsized boats do not sink, so characters who cannot get their
footing in the water are often able to hang onto the boat and float
downstream until they can refloat it.

Of course, if the boat was damaged at the time it capsized, the
holes must be repaired before refloating (see boatwright proficiency
on page 25).