Second part for documentation:
Why it is very important to have this rule:
A common British tactic to achieve Naval dominance is surprise attack: declare war on a potential future enemy with some of his fleet at sea, set your naval movement order to move before him and concentrate your entire fleet on a quick attack on his fleets. This is especially devastating against Spain - suppose he is tempted from joining France against GB - since you can move after France (thus using your fleet to keep the French one blockaded) and before Spain (thus attacking his ships with all your fleets). Next month, you simply switch your movement order to first and resume the blockade of the French fleet.
This way, with a single strike you can be sure to inflict heavy losses on your target (typically between 13 and 26 ships), while immediately recovering the pp's lost to declare War.
Naval evasion strongly limits this tactic, offering a 2 out of six chances for this surprise attack to fail. This way, you are not sure of recovering your lost pp's and you risk having to face a new enemy fleet at full strength. Without this rule, no fleet other then British will ever be safe outside a port, especially if within 7 sea zones from the Channel.
The original rule:
6.3.2 POSSIBLE EVASIONS: The major power upon which an attack is declared may attempt to evade unless the attack is caused by an interception or is in a port or blockade box. If the evasion is unsuccessful a combat will be fought. If the evasion is successful, the phasing player may not then attempt to attack any other stack remaining in the area.
18.104.22.168: Every time the phasing major power intends to attack a stack, the non-phasing stack may attempt naval evasion. This is done by the non-phasing stack's controlling player rolling a die. if a "1" or "2" is rolled, the non-phasing stack evades combat and is retreated according to the naval retreat after combat rules (see 22.214.171.124-treat the evading side as if it were the loser of a combat and the attacking side as if it were the winner).
126.96.36.199: There are no political points for a successful evasion.
NAVAL PURSUIT, EIA rule:
6.3.5 NAVAL RETREAT AND PURSUIT: The survivors of one side in a naval combat must retreat. Retreat moves are always made before pursuit moves and the retreat and pursuit moves of one naval combat must be made before the next naval combat is resolved.
188.8.131.52 SEA AREA RETREATS AND PURSUITS: The naval combat loser retreats all fleets that were in the combat to the one nearest unblockaded friendly (including an ally's port, with access permission and if the loser wishes to use it) port within seven movement points (losing player's choice if more than one possible port is equally close). Some, none or all of the victorious fleet(s) may pursue to follow the losing fleets and blockade that port.
184.108.40.206.1: If no eligible port is available, or at the loser's option, the loser retreats to any one adjacent sea area of the victor's choice (a sea area into which movement is not possible may not be selected). Retreating or pursuing fleets may not be intercepted. In this case there is no pursuit and the victor remains in the area where the combat occurred.
220.127.116.11.2: A fleet may neither retreat nor pursue into or through a sea area north of the ice line during winter or into or through the Dardenelles sea area without the permission of the major power controlling Constantinople (if any).
18.104.22.168 PORT RETREATS: If the naval combat takes place in a port, the attacking fleets (win or lose) must always retreat to the port's blockade box, and the defending fleets remain in the port (no pursuit).
22.214.171.124 BLOCKADE BOX RETREATS AND PURSUITS: If the naval combat takes place in a blockade box the loser must retreat to that port, if and only if, the combat resulted from the movement of the loser's stack from that port, and in any other case must retreat in accordance with sea area retreat rules (see 126.96.36.199). Pursuit is the same as a sea area pursuit. EXCEPTION: Since movement between a blockade box and its port is free (see 188.8.131.52), the victor (even if the phasing side with all movement expended) in a blockade box naval combat may be, if the port is friendly or with access permission, moved into the port following the naval combat.
184.108.40.206 NAVAL RETREAT AND PURSUIT EXAMPLE:
Continuing the example from 220.127.116.11; as the French Player lost (8 ships lost to 6) he must retreat to the nearest unblockaded friendly- controlled port within seven movement points or be moved by the British to an adjacent sea area. Great Britain gains "4" political points for the win (including "+1" extra for NELSON), and France loses "3" political points because the loser had 3 fleets. France decides to retreat to a nearby home nation port and Great Britain decides to follow up and blockade that port.
and finally, BRITISH TRAINING (an optional rule, to be true):
12.3.2 BRITISH TRAINING: Great Britain proved quite adept at turning certain minor country troops into first-class soldiers, notably the Portuguese and Hanoverian (the "King's German Legion" or "KGL") troops that they trained. Under this option, after 24 continuous months as a British-controlled minor free state, the morale of the army factors in the Hanover or Portugal corps is considered to be "4.0" for both infantry and cavalry in those corps. Garrison infantry factors of these nationalities retain their usual ("2.0") morale.