WHAT?:
When sailing towards an enemy ship while it also sails towards you, you can harpoon and lock in such a way that you and the opposing ship will whirl in a vortex while maintaining Cannon line.
(Can work on stationary ships with not too turbulant speeds)
HOW TO:
Sailing against a passing ship, you must use up a player for the Harpoon. He will then harpoon the front half of the targeted ship. And then hold on the LOCK (Not reel-in) function with the harpoon. Both ships will circle each other for that remainder.
I do not know the exact parameters of what makes a harpoon detach. But what has given me the best results is being at around the maximum range for the rope. Maximum range also gives good leeway for the cannons. Also (Unconfirmed) that you will have a smoother and less turbulent attachment if you attach around the center-front of the ship. (By center-front, I mean near the middle but still on the front half of a broadside)
If you are too close, I believe (untested) that you can unlock and then lock again, to lengthen the rope little by little. However, time is of the essence so this may not be worthwhile.
POSSIBLE TACTICS:
Naval Focus
When harpooning and circling, the cannoneers focus the opposing cannoneers for at least 2-4 shots per cannoneer, perhaps even focus firing the enemy helm. And only there after focus on giving leaking holes.
Boarding Focus
As soon as the harpoon catches the ship, one person jumps off and waits for the opposing ship to circle its way to the boarder. The boarder proceeds to board and attempt to anchor the ship. [Communicate to anchor your own ship there after to have a good angle]
Wrestle them into an Island
If close to an island, let go of circling with the opposing ship in such a way that they will be hurdling towards an island.
Things to keep in mind, if you are the harpooner, and you feel as if your ship unluckily happens to get the worse end of the deal, just let go.
I wish I could record one of these moments to show you how epic it looks and feels. And honestly, it does work Lethally well with a good crew, even with open crew it can work. Its a pretty solid Method that explains itself without communication on what to do.
Harpoon Ram
