Fleet Battles (OSS)

__TOC__
When whole fleets clash, the fates of nations might be at stake. Because such battles represent major events in the campaign, it is often best if the DM simply decides the outcome. To determine the result randomly, pair off the opposing ships and roll their maneuverability dice. If there is an odd number of ships, pit two or more ships from the larger force against ships in the smaller force. Modify the dice rolls as follows:
* The ship or ships with the greater number of marines and missile factors from artillery adds 1 to the dice roll for every five extra points. That is, a ship or group of ships that carries 25 marines and three medium ballistae (6 missile factors each for a total of 18 extra points) would have 43 points. If its opponents only had 20 marines, the first group of ships would gain a bonus of +4 (43-20-23+5-4.6 rounded down to 4).
* The ship or group of ships with the best ramming factor adds the difference between its ramming factor and that of the opponent to the die roll. That is, a ship with a ramming factor of 4 (or a group containing at least one ship with a ramming factor of 4) would get a +1 if the opposing ship had a ramming factor of only 3. The ship or group of ships with the best Seaworthiness rating adds one to the die roll for every 3 points of extra Seaworthiness. That is, a caravel (Seaworthiness 18) pitted against a dromond (Seaworthiness 8) would gain a bonus of +3 (18- 8-10+3=3.33, rounded down to 3).
The vessel with the higher roll wins the battle. Of course, the DM will have to use common sense to decide what "winning" really means. An outrigger that wins the die roll against a great galley might "win" by simply escaping without great harm to either side. Once a single round of combat is over, the DM can declare a winner (presumably the side that won the greatest number of dice rolls), or have the survivors fight another round. Each such round should take a half hour of game time.
DMs craving a less arbitrary method for resolving naval battles should pick up a copy of TSR's Naval Battle Rules: The Seas of Cerilia (#3134). Although this product is intended for use with the BIRTHRIGHT® campaign setting, the combat system can be used in any medieval campaign.
 Table 38: Ship Combat Statistics
 	Move 	Seaw.	Pursuit	Many. 	Size	RF	DefenseClass	Marines	Hull/CripplingPoints
Barge1 	3 	6 	1d6+1 	1d3 	M-VL	 	C 	2 	9/9
Canoe2 	6 	10 	1d6+2 	1d6+6 	S-M 	 	X 	0 	5/-
Caravel 	12 	18 	1d6+4 	1d6+1 	L 	0 	A 	20 	54/54
Cargo Ship 	6 	12 	1d6+2 	1d6 	L 	0 	A 	10 	36/36
Cog 	9 	17 	1d6+3 	1d6 	L 	0 	A 	5 	51/51
Curragh 	6/3/3 	10 	1d6+2 	1d6+4/1d6+5	S 	- 	C 	0 	5/5
Drakkar 	15/3/12	12 	1d6+5 	1d6+3/1d6+4	L 	1 	D 	160 	36/36
Dromond3 	18/6/12	8 	1d6+6 	1d6+2/1d6+3	VL 	3 	B 	0/100 	32/32
Fishing Boat 	6 	14 	1d6+2 	1d6+2 	M 	0 	C 	5 	21/21
Great Galley3	18/9/15	9 	1d6+6 	1d6+2/1d6+3	VL 	4 	B 	10/50 	36/36
Keelboat 	6 	8 	1d6+2 	1d6+1 	S 	- 	C 	6 	4/4
Knarr 	12/6/6 	16 	1d6+4 	1d6+1/1d6+2	L 	1 	D 	8 	48/48
Longship 	15/3/12	16 	1d6+5 	1d6+3/1d6+4	L 	1 	D 	150 	48/48
Manta 	18 	18 	1d6+6 	1d6+4 	VL 	4 	D 	200 	72/72
Outrigger4 	6/3/3 	14 	1d6+2 	1d6+3/1d6+4	M 	- 	C 	0 	21/21
Pentekonter3 	18/6/12	8 	1d6+6 	1d6+4/1d6+5	L 	2 	B 	0/50 	24/24
Raft5 	3 	6 	1d6+1 	1d3 	S-M 	- 	X 	0 	3/3
Skiff 	6 	10 	1d6+2 	1d6+5 	S 	- 	X 	0 	5/-
Sohar 	15 	15 	1d6+5 	1d6+2 	L 	0 	A 	10 	45/45
Trireme3 	21/6/15	8 	1d6+7 	1d6+2/1d6+3	VL 	3 	B 	0/30 	32/32
: 1 Increase the number of marines and hull points by 1 for every 10 feet above the standard length of 20 feet. Decrease the number of marines and hull points by 1 for every 10 feet below the standard length of 20 feet.
: 2 Increase hull points by 1 for every 10 feet above the standard 5 feet length.
: 3 The number before the slash indicates the vessel's normal passenger capacity. The number after the slash indicates the vessel's ability to carry marines in wartime.
: 4 Increase the outrigger's hull points by 1 for every 10 feet above the standard 30-foot length. Decrease seaworthiness and hull points by 1 for every 10 feet below the standard 30-foot length.
: 5 Increase the raft's cargo capacity by 3 tons and its crew capacity by one person for every 10 feet of the raft above the standard length of 10 feet. A raft gains a defense class of D if it is at least 30 feet long.
: Move: Movement rate. See the notes for Table 2: Ship Characteristics for details.
: Seaw: Seaworthiness. See the notes for Table 2: Ship Characteristics for details.
: Pursuit: The vessel's pursuit/flight rating, see the notes for Table 2: Ship Characteristics for details.
: Manv: Maneuverability Dice, see the notes for Table 2: Ship Characteristics for details.
: Size: See the notes for Table 2: Ship Characteristics for details. A vessel's size affects its efficacy in ramming maneuvers. See ram- ming maneuvers in the Nautical Combat chapter for more details.
: RF: Ramming factor. This refers to a vessel's ability to use its mass as an effective ram. Most ships possess numbers between 0 and 4 to indicate overall ramming ability. Vessels with ratings of 0 are not designed to ram other ships; however, their captains can still attempt to ram. Vessels with no ramming factor cannot attempt ramming maneuvers.
: Defense Class: Shows how much protection against missile fire a ship offers its crew and passengers. Most large sailing ships pro- vide Class A defense; the vessels have superstructures that give reasonable concealment, but leave sailors exposed. Large rowing vessels feature Class B defense; fewer people must brave missile fire to man the sails, but a volley of arrows can inflict considerable casualties among their rowers. Class C ships tend to be fairly small, though their crews can find some cover under the decks and rigging. Class D ships have no decking and very little rigging to provide cover from missile fire. Class X vessels are both open and very small.
: Marines: Any crewman or passenger who is active during a battle but not serving as an officer, sailor, or rower is considered a marine. Marines can serve as archers, artillerists, boarders, firefighters, or unassigned crew. A ship can have no more marines active than the value shown here. However, a ships' capacity for carrying marines can be increased by reducing its complement of sailors. For example, a caravel can have 20 marines, but it also can accommodate 40 sailors (see Table 2: Ship Characteristics). If 20 of those sailors are reassigned as marines, the caravel's total marine contingent rises to 40.
: Hull/Crippling Points: This represents the amount of damage a ship can withstand before cracking apart or becoming crippled. See the Resolution phase in this chapter for more details.