The galley sling is a strategy I came up with for AOE3 maps with significant amounts of water. It works best on the Caribbean, and Amazonian maps, however it can also be very effective on Yucatan and Patagonia. It is marginally successful on the Carolina and Saguenay maps. So far the only person to sucessfully counter it in FFA, 1v1 or team games has been Mokon.

Essentially the galley sling is a rush (on a water map no less) that is even more evil than skeletor. If done correctly you can leave your opponent with no dock and more importantly no TC by the 8 minute mark, possibly even the 7 minute mark if you execute it perfectly. I don’t know about you, but I know that when I loose my TC at 7 minutes it hurts like a motherf****. This strategy is incredibly effective because people just don’t see it coming and are simply floored by it. It works great in both 1v1 and team games, but be warned if you mess it up it can be quite hard to recover.
To perform the galley sling you will need to have the “Ship 1 free Galleon (or Fluyte) to the new world” card in your deck and you will need to be able to train grenadiers in age 2. This strategy has been tested with British and Russians only however I don’t see any real reason why it would not work for other civs that have access to the required card and grenadiers in age 2. For other civs this strategy may need to be tweaked as a result of different age up free resources. The Strategy works because people don’t expect a rush of this sort so quickly on maps with alot of water and often times lack the resources to hire mercenaries or have already spent their shipments on econ related items.

Below is a general outline, you may want to tweak it slightly to tailor it to your civ and the given map situation but this is the general outline.
Below the outline is a recorded game of the sling being used in a 3v3 on ESO2. My teamates are all LoL members.

At first this strategy can seem counter intuitive considering the map but that’s the way its supposed to be.

1. Start off as normal like you are playing a land only map. Don’t build a dock before advancing as you will need the wood to build houses since you wont have any villagers on wood early on. If your British use the starting wood to make house(s) and get your 1 or 2 free villagers. Put all villagers on food as they come out of the tc. Use your first shipment to send some free villagers, but save your second shipment it is important that you save it because you will need it shortly. You should aim to push advance at around 3:30 to 4:00 or so with 15-18 villagers. Upon clicking age up immediately send 4 villagers to mine gold and put 4 on wood, leave the rest on food.
   [Mazarin_LOL, who tested this as Russians for me notes that he sometimes has about 3-4 villagers on wood in age 1

2. As soon as you hit age 2 order the free galley from the HC and queue up some villagers in your TC and set the rally point on the closest tree’s. By this time you should have at least 800 food and hopefully about 300-400 or so gold. If you receive free gold from the age up at the TC (I do because I play British mostly) task a single gold miner on that.

3. As the galley arrives send it immediately to the enemy shore. While it is in route take 1 settler off of wood and have them build at least 1 house preferably 2 then re task him to wood. You should aim to be able to support at least 30 preferably 40 pop by the time the galley hits the opponents shore.

4. As soon as the galley reaches their shore beach it and use it to train 5 grenadiers. If the enemy dock is not in sight move the ship along the coast and march the grenadiers in the opposite direction. If you find the dock pull your galley right up alongside it and train 5 more grenadiers. Ignore any fire received from the dock or outpost if they are using one to protect the dock. If there is no dock at all precede direct to the opponents TC.

5. Task your 10 grenadiers on the dock it will go down in no time. They probably won’t have a chance to get out a ship. Use the galley to train longbows if you are British or skirmishers if your civ has those. You will use these to protect the grenadiers.

6. Immediately march inland and locate their TC (the quicker the better). Attack with you’re your grenadiers. Use your galley to train additional grenadiers as they really take buildings down fast and are effective against groups of villagers, like when they are grouped around a mine (hint hint). If you see them trying to throw up a barracks or stable task the grenadiers on it right away they will make short work of a partially completed foundation. The TC however is your prime objective it must be razed at all cost. If they call our militia split your grenadiers into 2 groups and separate them as they will most likely try to melee your grenadiers in that case let them militia beat up on the 1 group while you target them with the 2nd group of grenadiers and your support infantry.

7. Once the TC is down use the grenadiers to start razing the other buildings. This if all goes according do plan should be happening anywhere from around 6 minutes to 8 minutes into the game with 8 minutes being the latest really. Outposts come first (so they have no place to send shipments) followed by military buildings, then houses. Spread out your support infantry and blanket the area and pick off the villagers if your opponent has not already resigned. Start training cavalry to run down any hidden villagers.
   

The galley sling works in team games as well and has been tested in 2v2 and 3v3 games. It however has not been tested in 4v4 games and I personally don’t think it will be quite as effective in a 4v4.

In team games the ideal situation is for 2 players to perform the sling and target the same opponent so that you knock that person out of the game either permanently or at least for a good while. This can reduce a 3v3 to a 3v2, and while 2 players are rushing the third player can boom and make a strong navy to control the water.

In a 2v2 it is recommended that only 1 player rush while the other boom.

Recorded game of galley sling in action

Enjoy.